method on a wireless cellular telecommunications device housed in a server cell, wireless cellular t

专利摘要:
cell reselection in a cellular telecommunications network. according to one aspect of the present disclosure, a method can be provided in a wireless cellular telecommunications device housed provisionally in a server cell, the device storing a parameter obtained by decoding system information from a first cell. the method comprises: measuring an attribute of a signal received from a candidate cell; and evaluating the candidate cell for reselection based on the measured attribute according to a priority-based reselection algorithm independent of the stored parameter. the parameter indicates a minimum required received signal code power. a computer-readable device and media are also provided.
公开号:BR112013013379B1
申请号:R112013013379-1
申请日:2011-11-30
公开日:2021-02-23
发明作者:Raghavendra MAGADI RANGAIAH；David Philip Hole；Johanna Lisa Dwyer
申请人:Blackberry Limited；
IPC主号:

专利说明:

TECHNICAL FIELD
The present disclosure concerns a cellular telecommunications system and, in particular, a cell reselection method on a mobile device provisionally housed in a cell in the cellular telecommunications system. BACKGROUND OF THE INVENTION
In a typical cellular radio system, a wireless telecommunication device communicates through one or more radio access networks (RAN) with one or more major networks. In a UMTS system such devices are typically referred to as User Equipment (UE) and in a GSM system such devices are typically referred to as Mobile Stations (MS). The expressions can be considered as equivalent. In the description in this document, both expressions can be used interchangeably, however, it will be noted that the expression MS will be used predominantly, since the present disclosure relates primarily to cell reselection of a GSM EDGE Radio Access Network ( GERAN) for a terrestrial UMTS Radio Access Network (UTRAN) or an evolved Terrestrial UMTS Radio Access Network (e-UTRAN). It will be clarified, however, that the present disclosure is not limited to this type of cell reselection.
The Mobile Station (MS) comprises various types of equipment such as mobile phones (also known as cell phones or cell phones), laptops with wireless communication capabilities, tabular computers and personal digital assistants (PDAs) among others. These can be portable, handheld, pocket or installed in a vehicle, for example, and communicate voice or data signals or both with the radio access network (RAN). Certainly the MS may not be mobile, but it may be fixed in one location. In this context, the term mobile can refer simply to the communication capabilities of the device.
In the following description, reference will be made to the Global System for Mobile Communications (GSM), Universal System for Mobile Telecommunications (UMTS), Long Term Evolution (LTE) and for particular standards. However, it should be understood that the present disclosure is not intended to be limited to any particular mobile telecommunications system or standard.
The RAN covers a geographical area divided into a plurality of cell areas. Each cell area is served by at least one base station, which in UMTS can be referred to as an Node B or Node B enhanced in LTE. Each cell can be identified by a unique identifier that is spread across the cell. The base stations communicate on radio frequencies through a radio interface with the UEs that are temporarily housed in the cell (these can be some or all of the UEs that are within the range of the base station). Several base stations can be connected to a Radio Network Controller (RNC) that controls various activities of the base stations. RNCs are typically connected to a main network. Each cell implements a particular Radio Access Technology (RAT) such as UMTS Terrestrial Radio Access (UTRA) among others. In a GERAN (Global System for Mobile Communications (GSM) / radio access network for Enhanced Data Rates for GSM Evolution (EDGE)), the radio access network can include one or more base stations (BTSs) and one or more Base Station Controllers (BSCs) that jointly implement the Base Station Subsystem (BSS) functionality in relation to any particular cell.
Cell selection, sometimes referred to as cell search, for a UE is described in the 3GPP TS 25.304, V8.1.0 specification, “User Equipment (UE) procedures in idle mode and procedures for cell re-selection in connected mode” that is incorporated into this document by reference and referred to in this document as specification 25.304. Section 5.2.3, and in particular section 5.2.3.1.1, of specification 25.304 describes the cell selection process. One of the considerations in the cell selection process is whether a cell is "suitable". Criteria for suitability may include criteria related to signal strength and / or signal quality (referring to the signal transmitted by the candidate cell base station, as received by the UE). Some of the criteria that are used in the suitability assessment are based on parameters that must be decoded by the device after tuning to the candidate cell's frequency.
When idle, an MS will evaluate the properties of detected telecommunication cells, other than the cell to which it is currently connected or provisionally housed (often known as the serving cell), in order to identify whether the detected or candidate cells would be more appropriate for connection instead of the server cell. The process of MS to autonomously change the server cell while in idle mode is known as cell reselection (although reselection cannot be restricted to idle mode or purely autonomous cell change or both). The process by which an MS first provisionally lodges in a cell following activation or loss of radio coverage is known as cell selection. The criteria for cell reselection can include such things as received signal strength and signal quality. Parameters associated with these criteria can be broadcast or transmitted in another way in the server cell. One of the requirements for cell reselection (and selection) may be that the candidate cell is suitable. Criteria for suitability may include criteria related to signal strength and / or signal quality (referring to the signal transmitted by the candidate cell base station, as received by the MS). Some of the criteria that are used in the suitability assessment are based on parameters that must be decoded by the MS after tuning to the candidate cell frequency. Decoding the candidate cell parameters can require significant battery power for MS. Regular assessment based on decoding suitability parameters in this way is particularly undesirable on mobile devices where battery life is limited.
The existing solution to this problem is to store and reuse the most recently decoded fitness criteria parameters. This solution is outlined in the 3GPP TS 45.008 V9.4.0 specification, which is incorporated into this document by reference and referred to in this document as the '45.008 specification'. Section 6.6.5, section 6.6.6 and section 6.6.7 of specification 45.008 describe the cell reselection processes, entitled “Algorithm for cell re-selection from GSM to UTRAN”, “Algorithm for inter-RAT cell re- selection based on priority information ”and“ Cell selection and re-selection to CSG cells and hybrid cells ”, respectively. The algorithm defined in Section 6.6.5 can be described as the 'classification algorithm' and the algorithm defined in Section 6.6.6 can be described as the 'priority based algorithm'. These expressions can be used throughout the description in this document.
According to the existing solution, when assessing the suitability of a candidate cell, suitability parameters of a cell from which the suitability parameters were most recently decoded can be used. This solution, while it may reduce battery usage or MS's long-term power requirements, carries with it inherent limitations. Specifically, for example, it is easy for an MS to disregard the suitability of a candidate cell and thus not reselect to the cell when it should. This may be because the parameters used to assess their suitability are incorrect, for example, because the suitability parameters of the candidate cell are not the same as those being applied. Alternatively, an MS may incorrectly regard a cell as a valid cell for reselection and proceed, wastefully, to tune for the frequency of the candidate cell and decode parameters of that cell. This can be a particular problem if a wide range of threshold parameters is applicable for cells to which MS could potentially reselect. When one of these threshold parameters is stored, it can be used to incorrectly evaluate another cell in the network for which a different value is applicable.
In an example scenario, an operator may want idle devices to be temporarily housed in cells of one frequency, and devices in connected mode, that is, with active data or voice calls in progress, to operate on cells of a different frequency. . The operator can attempt to achieve this by discouraging idle reselection to a particular frequency by means of suitability criteria, that is, suitability criteria are established in such a way that it is very unlikely that an MS will be able to meet those criteria. In this scenario, MS can evaluate such cells for suitability using a considerable amount of energy in the process based on criteria that are easier to satisfy. Additionally, if the MS has stored these incorrect parameters for reuse in the suitability assessment for other cells, the MS may not be temporarily housed in a cell in which it must.
It would be desirable for a candidate cell meeting the reselection criteria not to fail in the adequacy aspect of the reselection tests. The present disclosure addresses the problem of how to efficiently and effectively evaluate a candidate cell for reselection. The present disclosure minimizes the need to tune for the frequency of a candidate cell and decode suitability parameters for candidate cells while avoiding the risk of incorrectly disregarding a candidate cell. BRIEF DESCRIPTION OF THE DRAWINGS
Examples of the present disclosure will now be described in detail with reference to the accompanying drawings, in which:
Figure 1A is a diagram showing an overview of a network and an UE device;
Figure 1B shows a schematic system suitable for implementing a first embodiment of the present invention;
Figure 2 shows a flow chart of a known classification algorithm for cell reselection;
Figure 3 shows a flow chart of a known method of storing suitability parameters when performing cell reselection;
Figure 4 shows a flow chart illustrating an example of the present disclosure in which stored suitability parameters are applied on a frequency basis;
Figure 5 shows an information flow view illustrating an example of the present disclosure in which stored suitability parameters are applied on a frequency basis;
Figure 6 shows a flow chart illustrating an example of the present disclosure in which stored suitability parameters are applied on a per cell basis;
Figure 7 shows a flowchart illustrating an example of the present disclosure relating to Closed Subscriber Group Cells (CSG);
Figure 8 shows a flow chart illustrating an example of the present disclosure relating to storage of suitability criteria;
Figure 9 shows a flow chart illustrating an example of the present disclosure relating to priority-based reselection;
Figure 10 shows a process illustrating an example of the present disclosure in which stored suitability parameters are applied on a frequency basis;
Figure 11 shows a process illustrating an example of the present disclosure in which stored suitability parameters are applied on a per cell basis;
Figure 12 shows a process illustrating an example of the present disclosure relating to Closed Subscriber Group Cells (CSG);
Figure 13 shows a process illustrating an example of the present disclosure relating to Closed Subscriber Group Cells (CSG);
Figure 14 shows a process illustrating an example of the present disclosure relating to Closed Subscriber Group Cells (CSG);
Figure 15 shows a process illustrating an example of the present disclosure relating to priority-based reselection; and
Figure 16 shows a flow chart illustrating an example of the present disclosure in which certain radio related assessments are not performed.
The same reference numbers used in different figures denote similar elements. DETAILED DESCRIPTION
Modalities established in this application relate in general to a method of cell reselection in an electronic device. Modalities can efficiently evaluate a candidate cell when performing reselection, without having to tune to the frequency of a candidate cell and decode the suitability parameters of that cell each time the evaluation is performed.
In accordance with an aspect of the present invention, a method is provided in a wireless cellular telecommunications device housed provisionally in a server cell, the device storing a parameter obtained from a first cell, the method comprising: measuring an attribute of a received signal a candidate cell; and evaluating the candidate cell for reselection, in which, if a carrier frequency of the candidate cell matches a frequency carrier of the first cell, the evaluation of the candidate cell for reselection is based at least on the measured attribute and the stored parameter, otherwise the evaluation the candidate cell for reselection is performed without using the stored parameter.
In accordance with an aspect of the present disclosure, a method may be provided in a wireless cellular telecommunications device housed provisionally in a server cell, the device storing a parameter obtained from a first cell, the method comprising: measuring an attribute of a signal received from a candidate UTRAN cell; and evaluating the candidate cell for reselection, in which, if a carrier frequency of the candidate cell matches a frequency carrier of the first cell, the evaluation of the candidate cell for reselection is based at least on the measured attribute and the stored parameter, otherwise the evaluation the candidate cell for reselection is performed without using the stored parameter.
In accordance with an aspect of the present disclosure, a method may be provided in a wireless cellular telecommunications device housed provisionally in a server cell, the device storing a parameter obtained from a first cell, the method comprising: measuring an attribute of a signal received from a candidate cell; and evaluating the candidate cell for reselection according to a classification algorithm, in which, if a carrier frequency of the candidate cell matches a frequency carrier of the first cell, the evaluation of the candidate cell for reselection is based on at least the measured attribute and the stored parameter, otherwise the evaluation of the candidate cell for reselection is performed without using the stored parameter. The candidate cell can be a UTRAN cell.
In certain embodiments, the method may further comprise performing reselection from the serving cell to the candidate cell based on the evaluation.
Additionally, if the frequency of the candidate cell matches the frequency of the first cell, the assessment may also include determining whether the candidate cell meets reselection requirements, where, if the measured attribute fails to exceed the parameter stored by a first predetermined quantity, the assessment includes determining that the candidate cell does not meet reselection requirements. The first predetermined amount can be +10 dB.
In addition, if the carrier frequency of the candidate cell does not match the carrier frequency of the first cell, the evaluation of the candidate cell for reselection may include: determining whether the measured attribute exceeds a predetermined standard value; and if the measured attribute fails to exceed the predetermined standard value, determine that the candidate cell does not meet the reselection requirements.
In addition, the first cell may be different from the server cell, the device having previously been housed provisionally in the first cell. Alternatively, the first cell and the candidate cell can be of the same wireless radio access technology.
In certain embodiments, the evaluation of the candidate cell may include: obtaining system information from the candidate cell, the system information including a parameter; determining whether the measured attribute exceeds the candidate cell parameter by a second predetermined quantity; and if the measured attribute exceeds the candidate cell parameter by the second predetermined quantity, reselect the candidate cell. The second predetermined amount can be 0 dB.
In addition, the stored parameter can indicate a minimum required receipt level. The measured attribute can be received signal code power (RSCP). In addition, the server cell can be a GERAN cell.
In certain embodiments, the method may additionally comprise: obtaining a parameter from a second cell; and if a carrier frequency of the second cell does not match the carrier frequency of the first cell, store said second cell parameter, otherwise if the carrier frequency of the second cell matches the carrier frequency of the first cell, replace the stored parameter with the second cell parameter such that when evaluating a candidate cell for reselection, if the carrier frequency of the candidate cell matches the carrier frequency of the second cell, the evaluation of the candidate cell for reselection is based on at least the measured attribute and the second parameter of stored cell. If the candidate cell has an identifier equivalent to an identifier of the first cell, the evaluation of the candidate cell for reselection can be based on at least the measured attribute and stored parameter, otherwise the evaluation of the candidate cell for reselection can be performed without using the stored parameter. The identifier can be a primary mix code.
In addition, the method may further comprise: determining whether a candidate cell is a closed subscriber group cell; and if the candidate cell and the first cell are cells of a closed group of subscribers, the evaluation of the candidate cell for reselection is based at least on the measured attribute and the stored parameter, otherwise the evaluation of the candidate cell for reselection is performed without using the stored parameter.
The server and candidate cells can be from the same wireless radio network. Alternatively, the server and candidate cells can be from different wireless radio networks.
In accordance with an aspect of the present disclosure, a wireless cellular telecommunications device adapted to: be temporarily housed in a server cell; store a parameter obtained from a first cell; measure an attribute of a signal received from a candidate UTRAN cell; and evaluate the candidate cell for reselection, in which if a carrier frequency of the candidate cell matches a frequency carrier of the first cell, the evaluation of the candidate cell for reselection is based at least on the measured attribute and the stored parameter, otherwise the evaluation of the candidate cell for reselection is executed without using the stored parameter.
In accordance with an aspect of the present disclosure, a wireless cellular telecommunications device adapted to: be temporarily housed in a server cell; store a parameter obtained from a first cell; measuring an attribute of a signal received from a candidate cell; and evaluating the candidate cell for reselection according to a classification algorithm, in which if a carrier frequency of the candidate cell matches a frequency carrier of the first cell, the evaluation of the candidate cell for reselection is based on at least the measured attribute and the parameter otherwise the evaluation of the candidate cell for reselection is performed without using the stored parameter.
In accordance with an aspect of the present disclosure, a computer-readable storage medium having instructions stored therein can be provided that can be executed by a device to: temporarily lodge in a server cell; store a parameter obtained from a first cell; measure an attribute of a signal received from a candidate UTRAN cell; and evaluate the candidate cell for reselection, in which if a carrier frequency of the candidate cell matches a frequency carrier of the first cell, the evaluation of the candidate cell for reselection is based at least on the measured attribute and the stored parameter, otherwise the evaluation of the candidate cell for reselection is executed without using the stored parameter.
In accordance with an aspect of the present disclosure, a computer-readable storage medium having instructions stored therein can be provided that can be executed by a device to: temporarily lodge in a server cell; store a parameter obtained from a first cell; measuring an attribute of a signal received from a candidate cell; and evaluating the candidate cell for reselection according to a classification algorithm, in which if a carrier frequency of the candidate cell matches a frequency carrier of the first cell, the evaluation of the candidate cell for reselection is based on at least the measured attribute and the parameter otherwise the evaluation of the candidate cell for reselection is performed without using the stored parameter.
In accordance with an aspect of the present disclosure, a method may be provided in a wireless cellular telecommunications device housed provisionally in a server cell, the device storing a parameter obtained from a first cell, the method comprising: measuring an attribute of a signal received from a candidate cell; and evaluating the candidate cell for reselection, in which, if the candidate cell has an identifier equivalent to an identifier of the first cell, the evaluation of the candidate cell for reselection is based at least on the measured attribute and the stored parameter, otherwise the evaluation of the candidate cell for reselection is executed without using the stored parameter.
In certain embodiments, if the candidate cell has an identifier equivalent to the identifier of the first cell, the assessment may include determining whether the candidate cell meets reselection requirements, where, if the measured attribute fails to exceed the parameter stored by a first predetermined quantity , the assessment includes determining that the candidate cell does not meet reselection requirements. The first predetermined amount can be 0 dB. Alternatively, the first predetermined amount can be +10 dB.
In accordance with an aspect of the present disclosure, a method may be provided in a wireless cellular telecommunications device housed provisionally in a server cell, the device storing a first parameter obtained from first cell system information, the method comprising: measuring an attribute of a signal received from a candidate cell; determine whether the candidate cell is a closed subscriber group cell; and evaluating the candidate cell for reselection, in which, if the candidate cell is determined to be a closed group cell of subscribers, the evaluation of the candidate cell for reselection is based on at least the measured attribute independent of the first stored parameter, said first stored parameter indicating a minimum value for the measured attribute.
In certain embodiments, the device has a second stored parameter obtained from a closed subscriber group cell and in which the first cell is not a closed subscriber group cell, where, if the candidate cell is determined to be a cell of closed group of subscribers, the evaluation of the candidate cell for reselection is based on at least the measured attribute and the second stored parameter.
In addition, if the evaluation is based on at least the measured attribute and the second stored parameter, the evaluation may include determining whether the cell meets reselection requirements, where, if the measured attribute fails to exceed the second stored parameter by a first predetermined quantity , determine that the candidate cell does not meet reselection requirements. The first predetermined amount can be 0 dB. Alternatively, the first predetermined amount can be +10 dB.
Additionally, if the candidate cell has an identifier equivalent to a second cell identifier and the candidate cell is determined to be a closed subscriber group cell, the evaluation of the candidate cell for reselection can be based on at least the second stored parameter, the otherwise the evaluation of the candidate cell for reselection is performed without using the second stored parameter.
The identifier can be a unique identifier locally. The identifier can be a physical layer identifier. The identifier can be a primary mix code.
In certain embodiments, if the candidate cell has a carrier frequency matching a carrier frequency of the second cell and the candidate cell has a primary mixing code matching the primary mixing code of the second cell and the candidate cell is determined to be a cell of a closed group of subscribers, the evaluation of the candidate cell for reselection is based on at least the measured attribute and the second stored parameter, otherwise the evaluation of the candidate cell for reselection is performed without using the second stored parameter.
In addition, if the evaluation is performed without using the stored parameter, the evaluation of the candidate cell may include: determining whether the measured attribute exceeds a predetermined standard value; and if the measured attribute fails to exceed the predetermined standard value, determine that the candidate cell does not meet reselection requirements.
The candidate cell can be a UTRAN cell. The candidate cell can be an E-UTRAN cell. The first cell identifier can also be a cell physical layer identifier. The server cell can be a GERAN cell.
In certain embodiments, the method may further comprise performing reselection from the serving cell to the candidate cell based on the assessment. The evaluation of the candidate cell can also include: obtaining system information from the candidate cell, the system information including a parameter; determining whether the measured attribute exceeds the candidate cell parameter by a second predetermined quantity; and if the measured attribute exceeds the candidate cell parameter by the second predetermined quantity, perform reselection for the candidate cell. The second predetermined amount can be 0 dB.
In addition, the stored parameter can indicate a minimum required receipt level. The measured attribute can be a received signal code strength (RSCP).
Also, the server and candidate cells can be from the same wireless radio network. Alternatively, the server and candidate cells can be from different wireless radio networks.
In accordance with an aspect of the present disclosure, a wireless cellular telecommunications device adapted to: be temporarily housed in a server cell; store a parameter obtained from a first cell; measuring an attribute of a signal received from a candidate cell; and evaluating the candidate cell for reselection, in which, if the candidate cell has an identifier equivalent to an identifier of the first cell, the evaluation of the candidate cell for reselection is based at least on the measured attribute and the stored parameter, otherwise the evaluation of the candidate cell for reselection is executed without using the stored parameter.
In accordance with an aspect of the present disclosure, a wireless cellular telecommunications device adapted to: be temporarily housed in a server cell; store a parameter obtained from system information of a first cell; measuring an attribute of a signal received from a candidate cell; determine whether the candidate cell is a closed subscriber group cell; and evaluating the candidate cell for reselection, where, if the candidate cell is determined to be a closed cell group of subscribers, the evaluation of the candidate cell for reselection is based on at least the measured attribute independent of the first stored parameter, the parameter indicating a minimum value for the measured attribute.
In accordance with an aspect of the present disclosure, a computer-readable storage medium having instructions stored therein can be provided that can be executed by a device to: temporarily lodge in a server cell; store a parameter obtained from a first cell; measuring an attribute of a signal received from a candidate cell; and evaluating the candidate cell for reselection, in which, if the candidate cell has an identifier equivalent to an identifier of the first cell, the evaluation of the candidate cell for reselection is based at least on the measured attribute and the stored parameter, otherwise the evaluation of the candidate cell for reselection is executed without using the stored parameter.
In accordance with an aspect of the present disclosure, a computer-readable storage medium having instructions stored therein can be provided that can be executed by a device to: temporarily lodge in a server cell; store a parameter obtained from a first cell; measuring an attribute of a signal received from a candidate cell; determine whether the candidate cell is a closed subscriber group cell; and evaluating the candidate cell for reselection, where, if the candidate cell is determined to be a closed cell group of subscribers, the evaluation of the candidate cell for reselection is based on at least the measured attribute independent of the first stored parameter, the parameter indicating a minimum value for the measured attribute.
In accordance with an aspect of the present disclosure, a method can be provided on a wireless cellular telecommunications device housed provisionally in a server cell, the device storing a parameter obtained by decoding system information from a first cell, the method comprising: measuring an attribute of a signal received from a candidate cell; and evaluating the candidate cell for reselection based on the measured attribute according to a priority-based reselection algorithm independent of the stored parameter, where the parameter indicates a minimum required signal code received power.
In certain embodiments, the method may further comprise performing reselection from the serving cell to the candidate cell based on the assessment. The evaluation of the candidate cell can also include obtaining system information from the candidate cell, the system information including a parameter; determine whether the measured attribute exceeds the candidate cell parameter by a predetermined amount; and if the measured attribute exceeds the candidate cell parameter by a predetermined amount, perform reselection for the candidate cell. The predetermined amount can be 0 dB.
Additionally, the evaluation of the candidate cell for reselection may include: determining whether the measured attribute exceeds a predetermined standard value; and if the measured attribute fails to exceed the predetermined standard value, determine that the candidate cell does not meet reselection requirements.
In certain embodiments, the measured attribute can be received signal code power (RSCP). The candidate cell can be a UTRAN cell. The server cell can be a GERAN cell.
In addition, the method may also comprise: measuring an attribute of a signal received from a second cell; and evaluate the second cell for reselection based on the measured attribute and the stored parameter according to a classification algorithm.
In addition, the server and candidate cells can be from the same wireless radio network. Alternatively, the server and candidate cells can be from different wireless radio networks.
In accordance with an aspect of the present disclosure, a wireless cellular telecommunications device adapted to: be temporarily housed in a server cell; store a parameter obtained when decoding system information from a first cell; measuring an attribute of a signal received from a candidate cell; and evaluating the candidate cell for reselection based on the measured attribute according to a priority-based reselection algorithm independent of the stored parameter, where the parameter indicates a required minimum signal code strength.
In accordance with an aspect of the present disclosure, a computer-readable storage medium having instructions stored therein can be provided that can be executed by a device to: temporarily lodge in a server cell; store a parameter obtained when decoding system information from a first cell; measuring an attribute of a signal received from a candidate cell; and evaluating the candidate cell for reselection based on the measured attribute according to a priority-based reselection algorithm independent of the stored parameter, where the parameter indicates a required minimum signal code strength.
Other aspects and resources of the present teaching will become apparent to persons of ordinary skill in the art upon review of the following description of specific modalities of a method and apparatus for cell reselection in a telecommunications system and the appended claims. Any method disclosed in this document can be implemented on a mobile station device on a wireless communications network.
Radio Access Networks type GSM / EDGE (GSM / EDGE Radio Access Network, GERAN), UMTS (Terrestrial Radio Access Network UMTS, UTRAN) or LTE (Terrestrial Radio Access Network UMTS evolved, e-UTRAN ) typically include multiple cells covering a geographic area, each of which can implement a different radio access technology (RAT). 2G can refer to GSM, and 3G can refer to UMTS and the terms can be used interchangeably. As previously described, a mobile station (MS) once connected to a cell, known as the serving cell, can evaluate other detected cells, known as candidate cells, to determine whether they would be more suitable for connection than the serving cell . When operating in a cell, the MS is referred to as being provisionally housed in the cell. In the description in this document the MS can be referred to as being "in a cell", "housed provisionally in a cell" or using a "server cell". These expressions can be used interchangeably and define that the MS is capable of being paged for downlink data by that cell. The description in this document can refer to 2G and 3G.
By the expressions ‘Classification Algorithm’ and ‘Priority Based Reselection Algorithm’ that are used throughout the description in this document, we intend the following:
In a classification algorithm, radio measurements of cells (possibly modified by displacements and / or scaling factors, and possibly subject to minimum thresholds) are compared and reselection in general is done for the best cell so classified. In a classification algorithm, cells at different frequencies, or using different radio access technologies, can be directly compared and thus classified in relation to each other. Radio measurements (or derived values, for example, based on a received cell signal quality or power) are the basic key for comparing candidate cells. An example of a classification algorithm is shown in figure 2.
In a priority-based reselection algorithm, cells (typically grouped according to their frequency of operation and / or radio access technology) are assigned priorities. These priorities are the primary resources by which cells are considered (radio measurements of neighboring cells being a secondary consideration) when determining which cell, if any, the device should reselect (it should be noted that other considerations can be made, such as based on in measurements of the server cell, in addition to the priority level). According to the current 3GPP priority-based reselection, priorities are assigned on a frequency basis (that is, in such a way that for all cells operating using the same radio access technology and the same carrier frequency, the same priority is assigned) , or (in the case of GSM cells) on a basis by radio access technology (cells operating according to GSM-based technologies operating on different carrier frequencies can be designated with the same priority). In particular, radio measurements of cells of different priorities do not need to be compared with each other (although radio measurements can be used for any cell, regardless of their respective priority, to verify that it meets the minimum criteria for temporary accommodation / service or to evaluate it against a threshold measurement). For example, a cell of a priority can be determined to satisfy all applicable reselection criteria, regardless of any radio measurements of a cell of a lower priority.
Referring to the drawings, Figure 1A is a schematic diagram showing an overview of a UMTS network and a user equipment device. Of course, in practice there may be many user equipment devices operating on the network, but for the sake of simplicity, Figure 1A shows only a single user equipment device 100.
For the purposes of illustration, Figure 1A also shows a radio access network 119 (UTRAN) used in a UMTS system having some components. It will be clear to those skilled in the art that in practice a network will include many more components than those shown.
Network 119 as shown in figure 1A comprises three Radio Network Subsystems (RNS) 102. Each RNS has a Radio Network Controller (RNC) 104. Each RNS 102 has one or more B 102 Nodes that are similar in function to a Transmitting Base Station of a GSM radio access network. User Equipment UE 100 can be mobile within the radio access network. Radio connections (indicated by the dotted straight lines in figure 1A) are established between the UE and one or more of the B nodes in the UTRAN.
Figure 1B shows an additional diagram of a network system. Typically each radio access network (RAN) includes radio access devices 156 to provide the radio link between the wireless communications device, the MS 160 and the rest of the radio access network. These radio access devices 156 are known as base stations in GSM and Nodes B in UMTS. The RAN in e-UTRAN comprises only e-Nodes B. In GSM and UMTS, the RAN also comprises a Radio Network Controller (RNC) or Base Station Controller (BSC), 152, 154, and the base stations; RNCs and BSCs are connected to one or more main networks (typically at least one for packet switched services and one for circuit switched services). RNCs connect to 3G base stations (Nodes B) and BSCs connect to 2G base stations (in which case the combined BSC and base station perform the functionality of a Base Station Subsystem (BSS)), even though they may be colocalized physically or in the same unit. The main network (not shown) is associated with a Public Land Mobile Network (PLMN) 150; it is possible for a single RAN to connect to core networks of multiple PLMNs (not shown).
Each 3G cell can be uniquely identified (within the local area) by a frequency and a primary mixing code. In general, a cell refers to a radio network object that can be uniquely identified by an MS 160 from a cell identifier that is broadcast in geographic areas by a base station, node B and node B or similar entity . A single physical Node B can generate more than one cell since it can operate on multiple frequencies, or with multiple mix codes or both. A candidate cell may at the end be connected to the same PLMN as the server cell.
Figure 2 shows a flow chart illustrating known processes performed by an MS during a known cell reselection procedure according to a classification algorithm. Referring to figure 2, the process starts at step 201. In step 202, cell measurements, for example, intrafrequency, interfrequency and inter-RAT cell measurements, are generated or received by the MS. In step 203, the classification values are calculated for each cell. In one example these cells are the serving cell and neighboring cells. An example of the calculation that can be used to calculate a classification value in the form of the R cell classification criterion is defined in section 5.2.6.1.4 of the 3GPP TS 25.304, V8.1.0 specification, “User Equipment (UE) procedures in idle mode and procedures for cell re-selection in connected mode ”which is incorporated into this document by reference and referred to in this document as specification 25,304 (see calculations for R, for server cells and R, for neighboring cells in this section). In this example, the classification values are calculated for cells if they satisfy the conditions established in section 5.2.6.1.4 of specification 25.304.
In step 204 the cells are sorted based on the sort values. In one example, only cells with classification values better than those in the server cell are considered and they are compiled into a list. In step 205 the resulting Cell Classification List is created. In step 206 if the MS finds that the server cell is better (that is, it has the highest rating value) then the MS remains provisionally housed in the server cell and the process returns to step 202.
If in step 206 the MS finds that the server cell is not the best (that is, it does not have the highest rating value) then in step 207 the MS tries to reselect a neighboring cell with the highest rating value. For this purpose, in 208 a channel (in one example a Primary Common Control Physical Channel (PCCPCH)) is established, in 209 the system information (in an example in the form of Master Information Blocks (MIBs) and Information Blocks System (SIBs) is read from the neighboring cell and in 210 a check is made that the cell is a suitable cell. A suitable cell is a cell in which an MS can be temporarily housed; examples include a cell that has acceptable signal strength and / or is not in an area of prohibited location and / or is not barred and / or for an automatic search, belongs to the correct Public Land Mobile Network (PLMN). If the cell is suitable for MS it is temporarily housed in the neighboring cell at 211. If the cell is not a suitable cell, the process returns to 202. The process ends in 212.
As noted earlier, the process shown in figure 2 requires that a communications channel be established with the candidate cell in order to determine the cell's system information and consequently the suitability of the cell for selection. In general, the described process of establishing a channel with the candidate cell is simply to allow the decoding of system information, which is broadcast. In the context of the present disclosure, establishing a communications channel does not necessarily imply any particular behavior by the network, that is, the network does not positively 'establish' the channel, since it can continuously broadcast system information.
This decoding is particularly energy intensive and time consuming for MS. If the serving cell is a GERAN cell, then it is likely to be frequently below a neighboring cell in the classification list as a result of the classification calculation. Consequently, MS may be repeatedly checking neighboring cells for suitability and, therefore, establishing communication channels in these cells to decode system information.
It may be the case that the system information received from neighboring cells contains a suitability parameter in such a way that it is unlikely that MS will always determine which cell will be suitable. The parameter may have been established by the network operator in such a way that the MS rarely, if ever, may vary from temporarily staying in that cell. In this scenario, the MS will repeatedly establish a communication channel in the cell using a large and unnecessary amount of energy in the process.
In an example scenario, an operator may want idle devices to be temporarily housed in cells of one frequency, and devices in connected mode, that is, with active data or voice calls in progress, to operate on cells of a different frequency. . The operator can attempt to achieve this by discouraging idle reselection to a particular frequency by means of the suitability criteria, that is, the suitability criteria are established in such a way that an MS will most likely not be able to meet those criteria. In the scenario indicated above, MS will consistently assess a cell like this for suitability using a considerable amount of energy in the process, even though the cell may never be suitable.
It was previously proposed that, in order to reduce the energy requirements of the MS, it can store previously decoded fitness parameters. The reason for requiring storage of suitability criteria is to allow the MS to evaluate a candidate cell, using these criteria, without having to first read the SIBs of the candidate cell (which would otherwise have to be read in order to determine the suitability criteria. applicable to that cell). In many cases, the cell would not meet the suitability criteria (based on the stored parameters) and no further evaluation of this cell is necessary; thus, storing criteria from a previous attempt can significantly reduce battery consumption since SIBs do not need to be read from cells that do not meet these criteria.
However, such storage can cause problems if the networks are configured as described above, particularly if the stored parameters are associated with a cell (that is, decoded from it) where reselection in idle mode is intended to be restricted, that is, those with unreachable (or rarely reachable) parameters. Since the stored suitability criteria are unlikely to be met, the MS will not attempt reselection (note that the MS can abandon reselection at this stage, without reading the target cell's system information and therefore without being able to determine that, in fact, the fit criteria would be met for this cell). In certain circumstances, the MS could remain provisionally housed in a GSM cell for longer than intended in instances where a UMTS cell would be more appropriate.
The suitability parameters or threshold criteria can indicate a minimum required receipt level. The signal quality, signal strength or signal strength of the cell may need to exceed this by a predetermined amount, for example, 0 dB or +10 dB. The suitability parameters or threshold criteria, in practice, can be the Qrxlevmin value or the Pcompensation value or both. Other suitability parameters or threshold criteria are certainly considered.
The stored Qrxlevmin value can have a range of - 115 to -24 dBm, and there is no default value (a value to be used if the value is not explicitly flagged), since its inclusion in the 3G cell system information is mandatory. Qrxlevmin can be a fitness parameter for that cell.
Pcompensation is an additional suitability parameter derived (at least partially) from one or more parameters disseminated in the cell, also commonly referred to in Section 6.6.5 of specification 45.008. Its value will most likely be 0 dB.
Figure 3 illustrates the known cell reselection process using stored parameters. The applicable algorithm is outlined in the 45.008 specification. Specifically, in section 6.6.5, entitled “Algorithm for cell re-selection from GSM to UTRAN”.
The illustrated process starts at step 302 with the MS provisionally housed in the server cell. Depending on the configuration and the algorithm used, the list of neighboring cells is received from the server cell (step 304) and the reselection parameters are decoded from that list (step 306). The MS then identifies a candidate cell and performs measurements (step 308). These may include signal strength and signal quality, among others. Then, in step 310, the MS determines whether the candidate cell meets the reselection criteria. This test can be limited to those criteria that can be derived from parameters received in the server cell. In some cases, depending on the parameters disseminated in the server cell and whether or not it has stored suitability parameters, the MS may omit to evaluate the candidate cell based on stored suitability parameters. If the candidate cell does not meet the reselection criteria, the process restarts since the cell is not acceptable (step 312).
Between steps 312 and 314 (not shown), if the serving cell transmits Received Signal Code Power (RSCP) parameters to be used instead of the 'suitability test' within the reselection algorithm, then the candidate cell is assessed against this regardless of whether or not it has suitability parameters stored. If this test is done and approved (not shown), the process moves to step 318.
If the candidate cell is acceptable, the MS checks whether it has suitability parameters stored from a previous attempt (step 314). If so, the candidate cell is evaluated to determine whether it meets suitability criteria based on these stored parameters (step 316). If the candidate cell does not meet the suitability criteria, the cell is considered unacceptable and the process is restarted (step 312). If the cell meets the suitability criteria based on the stored parameters, then the MS establishes a communication channel with the cell and obtains system information from the candidate cell (step 318). Similarly, if the MS does not have suitability parameters stored from a previous attempt, the MS establishes a communication channel with the cell and obtains system information from the candidate cell (step 318).
The suitability of the cell is then assessed using parameters in the system information (step 320). If the candidate cell meets the suitability criteria, the MS is temporarily housed in the cell (step 324). If the candidate cell does not satisfy the suitability requirements, the cell is considered to be unacceptable (step 312) and the MS remains provisionally housed in the server cell.
Section 6.6.5, “Algorithm for cell re-selection from GSM to UTRAN”, outlines the algorithm to determine the reselection suitability described above and based on a classification algorithm. The classification algorithm is used where priority-based reselection is not used, for example, because of network configuration or device capacity. Section 6.6.6, entitled “Algorithm for inter-RAT cell re-selection based on priority information” outlines priority based reselection. Typically, priority-based reselection is preferred. For example, a device that is capable of LTE must support priority-based reselection. In the classification algorithm, criteria for reselection from GERAN to UTRAN can be referred to as criteria based on CPICH RSCP. CPICH represents common pilot channel and RSCP represents Received Signal Code Power. For reference, an excerpt from the algorithm defined in section 6.6.5 of specification 45.008 is as follows, where FDD stands for Frequency Division Duplexing and MS stands for Mobile Station:
“If the 3G Cell Reselection list includes UTRAN frequencies, the MS should update the RLA_C value for the server cell at least every 5 s and for each of the at least 6 strongest non-server GSM cells.
The MS must then reselect a suitable UTRAN cell (see TS 25.304) if: - for a TDD cell the measured RSCP value exceeds the RLA_C value - for the server cell and all suitable non-server GSM cells (see 3GPP TS 03.22) by XXX_Qoffset value for a period of 5 s - for an FDD cell the following criteria are all met for a period of 5 s: 1. its measured RSCP value exceeds the RLA_C value for the server cell and for all suitable non-server GSM cells (see 3GPP TS 03.22) for the XXX_Qoffset value, 2. its measured Ec / No value is equal to or greater than the FDD_Qmin value, and 3. its measured RSCP value is equal to or greater than FDD_RSCP_threshold, if supported by MS. In the event that a cell reselection occurs within the previous 15 seconds, XXX_Qoffset is increased by 5 dB where - FDD_RSCP_threshold equals Qrxlevmin + Pcompensation + 10 dB, if these parameters are available, otherwise - “(ineffective criterion). - Qrxlevmin is the minimum RX level required in the FDD UTRAN cell (dBm), see 3GPP TS 25.304. - Pcompensation is max (UE_TXPWR_MAX_RACH - P_MAX, 0) (dB), see 3GPP TS 25.304. - UE_TXPWR_MAX_RACH is the maximum TX power level that an MS can use when accessing the FDD UTRAN cell in RACH (dBm), see 3GPP TS 25.304. - P_MAX is the maximum RF output power of the MS (dBm) in FDD UTRAN mode, see 3GPP TS 25.304. - FDD_Qmin and XXX_Qoffset are broadcast in BCCH of the server cell. XXX indicates another radio access technology / mode. Note: the parameters required to determine whether the UTRAN cell is suitable are broadcast in BCCH of the UTRAN cell. An MS can initiate reselection to the UTRAN cell before decoding the BCTR of the UTRAN cell, resulting in a small service interruption if the UTRAN cell is not suitable.
The MS can store the UTRAN cell RSCP suitability criteria parameters indicated above, whenever decoded from an FDD UTRAN cell from an equivalent PLMN. The most recently decoded parameters are valid reselection criteria for all FDD UTRAN cells. This parameter list must be cleared after selecting PLMN (see 3GPP TS 23.122) ”.
It should be noted that the definition of adequate in the algorithm indicated above requires that cell selection criteria are met. These criteria for UMTS cells are defined in the 3GPP TS 25.304 subclause 5.2.3.1.2 specification. The suitability parameters referred to in the 45.008 specification when defining reselection are Qrxlevmin and Pcompensation (which depends on UE_TXPWR_MAX_RACH). Specification 25,304 defines other parameters that affect suitability that are not used in the reselection tests defined in specification 45.008.
For later releases of the specification, the phrase “if supported by MS” in item 3 above has been removed, making this consideration mandatory for mobile stations in accordance with later releases of the specifications.
The definition of FDD_RSCP_threshold has also been modified previously to be read as follows: - “FDD_RSCP_threshold equals FDD_RSCPmin - min ((P_MAX - 21 dBm), 3 dB) if FDD_RSCPmin is broadcast in the server cell, otherwise Qrxlevmin + Pcompensation dB, if these parameters are available, otherwise the default value of FDD_RSCPmin ”.
In addition, the paragraph starting with “The MS can store” of the algorithm has been updated to be read as follows:
“The MS shall store the UTRAN cell RSCP suitability criteria parameters indicated above, whenever decoded from an FDD UTRAN cell from an equivalent PLMN while attempting to temporarily house itself in the FDD UTRAN cell. The most recently decoded parameters of an FDD UTRAN cell of an equivalent PLMN are reselection criteria valid for all UTRAN FDD cells. This parameter list must be cleared after selecting PLMN (see 3GPP TS 23.122) ”.
This change was made for the following reasons:
“If the FDD_RSCPmin parameters are not provided in the GSM server cell broadcast, the FDD_RSCP_threshold is derived from UTRAN cell broadcast information. These parameters can be different for each UTRAN cell.
It is not clear from which UTRAN cell and when the MS should read these parameters and when they should be read again. Furthermore, it is not clear whether a set of parameters of a UTRAN cell is valid for reselection for all cells or only for the UTRAN cell from which the parameters were read ”.
When this change to the specification was made, a summary was given as follows:
“It is clarified that the MS should restore the set of parameters when trying to temporarily host an FDD UTRAN cell of an equivalent PLMN and thus it is not required to read this parameter from neighboring UTRAN cells while temporarily hosting a GSM cell.
It is further clarified that the parameters received from a UTRAN cell are valid reselection criteria for all FDD UTRAN cells ”.
As stated above, the reason for requiring storage of suitability criteria is to allow the MS to evaluate a candidate cell, using these criteria, without having to first read the candidate cell's System Information Blocks (SIBs) (which would otherwise would have to be read in order to determine the suitability criteria applicable to that cell). In many cases, the cell will not meet the criteria and no further evaluation of this cell will be necessary; thus, storing criteria from a previous attempt can significantly reduce battery consumption since SIBs do not need to be read from cells that do not meet these criteria.
It was mentioned earlier that Section 6.6.5 applies only where priority-based reselection is not used. Specifically, Section 6.6.5 reports: “The algorithm in this sub-clause must be used for GSM to UTRAN reselection if the conditions for using the cell reselection algorithm based on priority information (see sub-clause 6.6.6) are not met. satisfied. Section 6.6.6, “Algorithm for inter-RAT cell re-selection based on priority information”, defines which priority-based reselection criteria allow an operator to configure a set of cells (at the same frequency and using the same RAT) as having a particular priority; Different priorities can be assigned to different RATs or frequencies or both. Multiple frequencies from the same RAT can share a priority level. Two frequencies cannot share a priority level if they are used for different RATs. As with the algorithm defined in section 6.6.5 and discussed earlier, there is a requirement that the target or candidate cell is suitable as defined in specification 25.304 and described earlier. For reference, an excerpt from the algorithm defined in section 6.6.6 of specification 45.008 is as follows: “The MS should then reselect a suitable cell (see 3GPP TS 25.304 for UTRAN and 3GPP TS 36.304 for E-UTRAN) from another technology radio access if the following criteria are met. S_non-serving_XXX is the measurement quantity of a non-server inter-RAT cell and XXX indicates the other radio access technology / mode and is defined as follows: - for a UTRAN cell, it is the RSCP value measured for the least cell UTRAN_Qrxlevmin for the cell frequency; - for an E-UTRAN cell, it is the RSRP value measured for the cell minus E-UTRAN_Qrxlevmin for the cell frequency if THRESH_E-UTRAN_high_Q is not provided; otherwise, if THRESH_E-UTRAN_high_Q is provided, it is the value
RSRQ measured for the cell minus E-UTRAN_QQUALMIN for the cell frequency. (...)
Cell reselection to a cell from another inter-RAT frequency must be performed if any of the following conditions (to be evaluated in the order shown) are met: - The S_non-serving_XXX of one or more cells from an inter-RAT frequency higher priority is greater than THRESH_XXX_high (or, in the case of an E-UTRAN target, THRESH_E- UTRAN_high_Q, if provided) during a T_re-selection time interval; in this case the mobile station must consider the cells for reselection in decreasing order of priority and, for cells of the same inter-RAT frequency or of inter-RAT frequencies of equal priority, in decreasing order of S_non-serving_XXX, and reselect the first cell that satisfy the conditions indicated above; - the value of S_GSM is less than THRESH_GSM_low for the server cell and for all GSM cells measured during a T_re-selection time interval; in this case, the mobile station should consider inter-RAT cells for reselection in the following order, and reselect the first cell that meets the following criteria: - cells of a lower priority inter-RAT frequency whose S_non-serving_XXX is greater than THRESH_XXX_low ( or, in the case of an E-UTRAN target, THRESH_E- UTRAN_low_Q, if provided) during a T_re-selection time interval; these cells must be considered in decreasing order of priority and, for cells of the same RAT, in decreasing order of S_non-serving_XXX; - if cells do not meet the criteria indicated above, inter-RAT cells for which, during a T_re-selection time interval, S_non-serving_XXX is greater than S_GSM for the server cell by at least one specific H_PRIO hysteresis; these cells should be considered in decreasing order of S_non-serving_XXX.
An FDD UTRAN cell should be reselected only if, in addition to the above criteria, its measured Ec / No value is equal to or greater than FDD_Qmin-FDD_Qmin_Offset.
If E-UTRAN_Qmin is provided for an E-UTRAN frequency, an E-UTRAN cell at that frequency should be reselected only if, in addition to the above criteria, its measured RSRQ value is equal to or greater than E-UTRAN_Qmin.
If THRESH_E-UTRAN_high_Q is provided for an E-UTRAN frequency, and if E-UTRAN_RSRPmin is provided, an E-UTRAN cell at that frequency should only be reselected if, in addition to the above criteria, its measured RSRP value is equal to or greater than E- UTRAN_RSRPmin. If E-UTRAN_RSRPmin is not provided, the default value must be used.
E-UTRAN cells that are included in the list of disallowed cells should not be considered as candidates for cell reselection. If the strongest cells on an E-UTRAN frequency are included in the list of disallowed cells, the mobile station can reselect the strongest valid cell (see sub-clause 8.4.7) on that frequency.
Cell reselection to a cell from another radio access technology (for example, UTRAN or E-UTRAN) should not occur within 5 seconds after the MS has reselected a GSM cell from an inter-RAT cell if a suitable GSM cell can be found.
If the mobile station applies common priorities or individual priorities received through dedicated signaling and priorities are only available for some inter-RAT frequencies, cells belonging to frequencies for which no priority is not available or no threshold is not provided by the non-serving cell should be considered for measurement and cell reselection.
If a mobile station in the 'normally provisionally housed' state (see 3GPP TS 43.022) applies individual priorities received through dedicated signaling and no priority is not available for the server cell, the mobile station must consider any GSM cell (including the server cell) to have a lower priority (that is, less than the eight values configured per network).
A mobile station in the ‘provisionally housed in any cell’ state (see 3GPP TS 43.022) must ignore individual priorities received through dedicated signaling and must apply priorities received from the server cell’s system information while trying to discover a suitable cell. If the mobile station supports CS voice services, the MS should avoid reselecting acceptable (but not suitable) E-UTRA cells regardless of the priorities provided in the system information.
NOTE 4: If the MS is temporarily staying in an acceptable cell, individual priorities are not discarded until an event resulting in their elimination occurs ”.
If a cell supports priority-based reselection according to section 6.6.6 of specification 45.008, it will transmit to a MS provisionally housed in the cell a list of its neighboring cells - the 'list of neighboring cells' (it can identify individual cells, or frequencies on which neighboring cells operate, or both). Along with the list, a message of Type Two Rooms of System Information (SI2quater) can indicate a parameter applicable to one or more cells in the list, referred to as UTRAN_Qrxlevmin in the excerpt above. This candidate cell parameter, which is broadcast in the server cell, that is, the UTRAN_Qrxlevmin, is expected to be in normal operation closely related to the corresponding RSCP threshold sent by the respective cell (s) as used in the fitness check. As such, this parameter allows the MS to identify whether the cell meets a criterion based on RSCP without energy-intensive decoding and evaluation of system information disseminated by the candidate cell unless that criterion is met.
However, support for priority-based reselection remains optional for non-LTE enabled devices. For LTE-enabled devices, priority-based reselection should be used. In addition, priority-based reselection is not supported on any pre-Release 7 devices. Furthermore, there is a possibility that priority-based reselection is not applicable in the server cell, for example, if the cell is a GERAN cell. It is very possible that operators will not update GERAN networks to support priority-based reselection, even when LTE is implemented, especially near the edges of the LTE coverage. Therefore, while LTE cells or UTRAN cells will most likely support priority-based reselection, overlapping or nearby GSM cells will not be able to. A device supporting priority based reselection is required to use the old 6.6.5 rules, that is, reselection according to the classification algorithm, in a case like this. In this scenario, the problems described above are applicable; where an MS can remain provisionally housed in a GSM cell for longer than appropriate when a UMTS or LTE-enabled cell is available, but the MS does not consider it to be adequate or receive and decode energy-intensive system information required.
The RSCP threshold parameter of priority based reselection (PBR) broadcast in the server cell is optional and is established in the network configuration. The parameter is likely to be (or correlate with) the required minimum measured RSCP level. In addition, the PBR parameter can be broadcast as a specific value and associated with one or more frequencies explicitly flagged, or it can be broadcast as a 'standard' value to be used with cells of non-flagged frequencies explicitly together with the parameter value. The parameter is applicable only to cells that operate on the same frequency associated with the parameter. The default value only applies to frequencies in the list of neighboring cells. An example of a standard diffusion parameter is the DEFAULT_UTRAN_QRXLEVMIN parameter encoded within the
Description of 3G Priority Parameters; an example of a parameter associated with explicitly flagged frequencies is the UTRAN_QRXLEVMIN parameter encoded within the Repeated UTRAN Priority Parameters structure (see 3GPP TS 44.018 v.10.3.0). If no parameters are not broadcast in the cell, the algorithm specifies a value to be used, that is, just like the UTRAN_Qrxlevmin. The PBR parameter may not have been broadcast in the cell due to network configuration or may not have been received entirely by MS.
For the purposes of this discussion, a network comprising three cells can be considered, although it is understood that this is just an example and more cells implementing a variety of Radio Access Technologies (RATs) can also be used with the present disclosure. In the examples described, unless otherwise indicated, a first candidate cell, cell A, is a UTRAN cell. Another cell, cell B, is the cell currently serving MS and is a GERAN cell. Another cell, cell C, is a second candidate cell and is also a UTRAN cell. Although GERAN and UTRAN cells are used in this description, it should be understood that any RAT can be implemented by each cell, however, for the purposes of disclosure, cells A and C must be implementing the same RAT.
As described, referring to the nomenclature indicated above, when an MS is connected or, as is known, temporarily housed in cell B (the serving cell), the MS can evaluate cells A and C to determine their suitability for reselection .
During GSM cell reselection to UMTS or LTE, section 6.6.5 of the existing 3GPP TS 45.008 described earlier, ie reselection according to a classification algorithm, sends storage and, in some cases, use of received suitability requirements previously for FDD UTRAN cells.
The 45.008 specification refers to “Equivalent PLMNs”, which may include the registered PLMN (in general, these procedures are agnostic for which PLMN is being considered as long as it is within the list of equivalent PLMNs - PLMNs in this list are “ considered as equivalent to each other for PLMN selection, cell selection / reselection and transfer between cells ”; TS 23.122 sub-clause 4.4.3). The text goes on to indicate that these values are taken from PLMN selection; however, reselection between different equivalent PLMNs is not considered to be PLMN selection.
This can result in a scenario where, for example, transfer scenarios between national service areas where two operator PLMNs are defined as equivalent to each other, suitability criteria for a transfer partner between service areas are applied to a cell a second transfer partner between service areas (or the home or server PLMN). The use of equivalent PLMNs is up to the operator (s) to determine and the scope of these problems is not limited to how or why equivalent PLMNs are used, or whether they are used in any way.
More importantly and more generally, there is a potential in which threshold criteria for one cell or category of cells (such as those operating at a particular frequency) are different from those for another cell or category of cells (such as such as those operating on another frequency, on the same PLMN or on a different equivalent PLMN), then the behavior of the mobile station will vary considerably depending on stored requirements, which in turn may depend on the most recent UTRAN cell from which it received (and stored) the requirements.
More specifically, we can consider an exemplary scenario where an operator wants idle devices to be temporarily housed in cells of a frequency, and devices in connected mode (that is, with active data / voice calls in progress) to operate in cells of a frequency. different frequency. The operator can try to achieve this by discouraging (to the point of making it practically impossible) reselection in idle mode to a particular frequency by means of suitability criteria; that is, the suitability criteria are established in such a way that a piece of furniture will most likely not be able to meet these criteria.
According to existing rules, the UE can store and apply these same criteria (which it decoded as part of an attempt - most likely unsuccessful - to reselect to a cell at the first frequency) when evaluating a UTRAN cell at any frequency, including cells in the second frequency where reselection in idle mode is not intended to be restricted.
Since the stored criteria will most likely not be met, the MS will not attempt reselection (noting that the MS can abandon reselection at this stage, without reading the target cell's system information and therefore without being able to determine that, in fact, , the suitability criteria would be satisfied for this cell).
This problem could potentially restrict 2G cell reselection to 3G causing the device to become essentially stuck in 2G (or at least, stay there longer than intended). In some cases the device can move to 3G only if power is turned off or PLMN reselection happens (see 3GPP TS 23.122).
In the case of priority-based reselection, considering the exemplary case where a cell has stored very strict cell criteria, this may lead to inadequately abandoning the evaluation of a second cell as part of the priority-based reselection, even if all the criteria (correct) ) to allow reselection evaluation to be available in the server cell.
In addition to the scenarios indicated above, additional problems are created by the use of Closed Subscriber Group (CSG) cells. Residence Node B (HNB), Residence eNB (HeNB) or femtocell are concepts introduced for UMTS and LTE (E-UTRAN) to improve indoor and microcell coverage as well as to optimize cable line return network for ' residence'. It should be noted that “femtocell” is widely used outside of 3GPP to mean any cell with a very small coverage, and is typically installed in a private enclosure (private or corporate). The terms HeNB / HNB are used in 3GPP with specific meanings, that is, the cell is a Closed Subscriber Group (CSG) cell, or hybrid cell.
An important aspect of the HeNB / HNB functionality is the ability to restrict access to private users. For example, for employees of the company on whose site H (e) NB is implemented, for customers of a private coffee shop chain, or (in the case of H (e) NBs implemented in private homes) for individuals.
To achieve this functionality, 3GPP defined the concept of a Closed Subscriber Group. A CSG cell is one that indicates that it is a CSG cell (by means of 1 bit broadcast in the system information) and broadcast a CSG ID (also in the system information). One cell can indicate only one (or no) CSG ID, however multiple cells can share a CSG ID. One device (UE or MS) can be enrolled in multiple CSGs. Such registrations can be temporary in nature (for example, a cafeteria allows a customer access to your CSG for 1 hour).
CSG cells are a specific category of cells, which can be used as “femtocells” or to provide uncoordinated coverage (ie, not subject to normal radio planning as used for “macrocells”) or both. They can be limited to users with specific enrollments (for example, associated with an employer, school / university, cafeteria, etc.)
The term “macrocell”, while not important in 3GPP specifications, is widely used to mean a cell other than a CSG cell and is used in this way in this description.
A CSG cell can operate using UTRAN or E-UTRAN protocols and radio specifications, and can operate on the same or a different frequency than the frequency for non-CSG cells.
CSG UMTS cells will not be listed in neighboring cell lists of non-CSG cells; therefore, legacy UMTS devices (that is, Release 7 or earlier) will not search for such cells. If such a device attempts to access a CSG cell, its registration attempt will be rejected.
E-UTRAN is specified first in Release 8 and, therefore, all E-UTRAN enabled devices will necessarily be “CSG aware” devices, even if they do not have CSG enrollment.
Reselection criteria for these cells are different. The cell is simply required to be suitable, the strongest in frequency and accessible to the device (for example, it has an inscription for the cell).
In general, network operators are very interested in which devices that have an inscription for a CSG cell are temporarily housed in that cell at the expense of a non-CSG cell. However, the device's determination to search for CSG cells is implementation specific, and can be activated manually. It is expected that devices will store some information (such as GPS coordinates, a list of macrocells that are detected) corresponding to the location of cells that they are able to access and that they will use this to speed up subsequent accesses - this is referred to as 'fingerprint'.
The decision of which target cell to provisionally host is also dependent on the cell selection and reselection rule defined for UTRAN and E-UTRAN. Currently, in Release 8, it is specified that a UE can reselect to a cell only if it is the best cell (that is, the cell with the strongest signal strength) of any cells using its particular carrier frequency. It is also specified that while the UE is provisionally housed in a suitable CSG cell, the UE should always consider the current frequency to be the highest priority frequency.
Idle reselection away from CSG cells towards a non-CSG cell follows legacy behavior for reselection for such cells. However, parameters for cell reselection to CSG cells are unlikely to be available in the server cell and, therefore, there is no suggestion for the device as to what criteria they may be (as it exists in the case of priority based reselection, as described previously) ). In addition, these cells are likely to be configured to provide very limited coverage, meaning that their suitability requirements can be relatively stringent when compared to those of non-CSG cells. Storing suitability requirements for CSG cells and using them in non-CSG cells (or vice versa) can result in very infrequent reselection attempts (because the stored criteria are too high), or exhausted battery life (if cells are incorrectly determined to meet suitability requirements before reading the candidate cell's system information). Even between CSG cells, different cells can have very different requirements.
CSG cells can be identifiable as such based only on their physical layer identities (frequency, physical layer identity, primary mix code, etc.) - because they operate on a dedicated frequency or because the range of physical layer identities is transmitted on the network.
Hybrid cells (introduced in Release 9) are also an additional category of cells that may have different suitability requirements than those of non-hybrid cells.
In E-UTRAN, lists of neighboring cells are not explicit, that is, they do not positively identify cells: they simply indicate a frequency and, optionally, a list of “Not Allowed” cells (list of blocked) that furniture should not attempt to access . Devices are expected to detect cells at a frequency through blind scanning. However, this can result in a significant problem in the case where many of the detected cells are CSG cells. In order to minimize unnecessary processing of such cells by devices that do not have a CSG enrollment, the network can optionally indicate the applicable “PCI division” for CSG cells, that is, the set of physical layer cell identifiers / identifiers that are reserved for CSG cells.
The PSC division is the analogous indication for UMTS cells, if an operator lists CSG cells in the list of neighboring cells.
It has also been discussed to use a PCI / PSC division to distinguish between hybrid cells and non-hybrid cells.
It is important to note that CSG cells can have significantly different criteria for reselection (when compared to other non-CSG cells, or possibly even when compared to other CSG cells) and that they can be identifiable as CSG cells without the need to decode information from diffusion system (for example, based on physical layer parameters: frequency / PSC / PCI, etc.), as previously described.
There is currently no solution to solve the problems identified and described previously. Example of the Present Revelation
According to the present disclosure, it is proposed that decoded cell threshold criteria be stored and used selectively in order that the evaluation of candidate cells is efficient and more accurate than that of existing solutions.
It is proposed and described through exemplary implementation, that storage and use of stored suitability requirements discriminates between cells (or classes of cells) that can be broken down into the physical layer, for example, where physical layer addresses (or ranges of them) and / or operating frequencies are used to distinguish categories of cells. In this way, an MS can discriminate stored fitness requirements according to a cell class or an individual cell without having to establish a communication channel in that cell. In one example, requirements are used according to the frequency of the cell or the identity of the cell. In one example, requirements for CSG cells versus non-CSG cells are exemplary discrimination (CSG cells are likely to use a dedicated range of physical layer addresses, which can be PCI (E-UTRAN cells) or PSC (UTRAN cells)) . In addition, use of stored parameters can be restricted to individual CSG cells (that is, they can only be used in evaluating the same cell from which they were received).
In addition, previously stored suitability requirements (which may have been obtained as a result of classification based reselection) should not be used when evaluating cells according to priority based reselection rules. This can be dependent on whether the corresponding parameters (signal quality / signal strength) are available in the current server cell. The network can be configured not to send these parameters, that is, the parameters may not be included in the system information of the current server cell.
In a first embodiment, threshold criteria are stored and used according to the frequency of the applicable cell. For example, threshold parameters are stored in the device and linked with the frequency of the cell from which they were decoded. These parameters are then to be used only when evaluating cells of that frequency. In this way, configurations defined by a network of cells having particular frequencies are prevented from causing an MS to remain provisionally housed in a cell. In an additional example, for priority based reselection, threshold criteria can be stored and reused on a priority level basis.
As illustrated in figure 4, storage and use of stored fitness requirements can be on a frequency basis. In other words, requirements decoded from a cell at frequency A are used only for evaluating other cells at the same frequency.
The illustrated process begins with the MS being provisionally housed in a server cell. In this description, the serving cell can be described as the 'B cell'. The server cell can be any RAT, but in this example it can be considered as a GSM cell for convenience. It is irrelevant whether the MS has temporarily housed itself in the serving cell when using cell reselection or cell selection. Optionally, the MS will obtain the list of neighboring UMTS or LTE cells. This can be diffused in the server cell or can be obtained in another way (step 404). The reselection parameters can be decoded from the list of neighboring cells (step 406).
Once these optional steps have been performed, the MS can then identify a candidate cell. This may or may not be in the list of neighboring cells. The MS then obtains measurements from the identified cell to identify cell characteristics such as signal strength, signal quality or signal strength (step 408). It will be understood that the steps can be performed in any particular order. In a specific example, measurements can be considered to be performed for all cells in the list before a candidate cell is identified.
Once a candidate cell has been identified and measurements of that cell have been performed, the MS determines whether the cell meets initial reselection requirements (step 410). This test can be based on the decoded parameters of the server cell in the list of neighboring cells. If the cell is found not to meet these initial reselection requirements, then the MS will remain provisionally housed in the serving cell and will not continue the reselection process.
If the MS determines that the cell meets the initial reselection criteria, then the MS will verify that it has any related stored criteria for suitability previously decoded from another cell (step 412). The parameters may have been decoded from a cell's system information when assessing the suitability of the cell. If the MS has stored criteria, the MS will then determine whether the criteria are for a cell having the same frequency as the candidate cell (step 414). The criteria must have been decoded from the system information of a cell operating at the same frequency as the candidate cell. To enable this, the MS may be required to maintain an indication of the frequency of the cell from which the criteria were determined, in association with the criteria in the data store. In this description, the candidate cell can be referred to as the 'C cell' for convenience.
If the parameters are determined to be from a cell having the same frequency as the candidate cell, the candidate cell is checked for suitability for reselection (step 416). The stored criteria, from a previous suitability check, are used to determine whether the cell meets these requirements. In one example, the measurements performed by the MS are used to determine whether the cell meets a particular threshold. If the candidate cell does not meet or exceed the requirements based on the stored parameter, for example, the characteristics of a signal received by the cell's MS do not exceed the threshold indicated by the parameter, the process is interrupted and the MS remains temporarily housed in the server cell. It should be noted that the signal attribute (s) may have to exceed the threshold by a predetermined amount, which, for example, may be 0 dB or +10 dB. The parameter can be the minimum receipt level, the QRXLEVMIN value.
Conventionally, a stored Qrxlevmin value can range from -115 to -24 dBm, and there is no standard value, as its inclusion in the 3G cell system information is mandatory. Qrxlevmin can be a fitness parameter for that cell.
Pcompensation is an additional suitability parameter derived (at least partially) from one or more parameters disseminated in the cell also referred to currently in Section 6.6.5 of specification 45.008. Its value will most likely be 0 dB.
If, based on the parameter, it is determined that the candidate cell meets or exceeds the requirement then the MS can continue to further evaluate the cell in the known way, for example, by tuning to the frequency of the cell and evaluating it using decoded data. If the MS has no stored criteria available (step 412) or if the MS has no stored criteria obtained from a cell having the same frequency as the candidate cell (step 414), then this decoding is performed.
Optionally, before obtaining the candidate cell's system information to decode suitability parameters in step 418, it is not shown that the MS can evaluate the candidate cell using standard parameters that are not explicitly flagged. In one example, the default parameter is a predetermined quantity and is defined in the reselection specification. If the candidate cell does not meet the requirements based on this standard parameter, the MS does not continue with the reselection and the MS remains provisionally housed in the server cell. If the MS meets these requirements based on the standard parameter, the MS continues with the reselection process.
In the illustrated example, in step 418, the MS can obtain the system information from the candidate cell. To do this, the MS can establish a communication channel in the cell and tune to its frequency. The system information can be in the form of a System Information Block (SIB) and can be obtained by tuning to the frequency of the cell and establishing a communication channel in it. The system information is generic and can be derived from blocks other than the SIB referred to throughout the present disclosure. The MS will then decode the system information to obtain suitability parameters and evaluate the cell based on these parameters (step 420). If it is determined that the MS meets these requirements (step 422), for example, based on the measurements performed previously in addition to the decoded parameters, the MS can temporarily lodge in the candidate cell and perform reselection for it (step 424). If the DM is found to be inadequate, the DM will remain provisionally housed in the server cell.
Additionally and optionally, a record update can be performed when the MS has been temporarily housed in the new cell (not shown). This registration update can explicitly notify the network that MS has reselected to a new cell or new registration area. Additionally and optionally, data can be transmitted and received via the network in the new cell (not shown). The record update step (not shown) may include, for example, a routing area update, location update, combined routing area update or similar. For additional information regarding the registration update, please see the 3GPP TS 24.008 specification, “Mobile radio interface Layer 3 specification; Core network protocols; Stage 3 ”, which is incorporated into this document by reference.
Figure 5 provides a high-level view of the information flow. When an MS is provisionally housed in a 3G 504 cell, the RSCP suitability criteria parameters are stored according to the frequency of the cell. This 506 storage can contain multiple parameters and frequencies. As shown, when performing cell 2G to 3G reselection, that is, from cell 502 to cell 504, the stored information is used on a frequency basis.
In order to produce the previous example, it may be advantageous for an MS to maintain a list of frequencies and threshold parameters. For example, for each cell having a new frequency found, the threshold parameters for that frequency are stored. In addition, each time new threshold parameters are decoded from a cell having a particular frequency, the stored criteria can be overridden. This can occur once the MS has decoded a cell's system information (step 420) if the cell previously meets the criteria (step 616).
In another mode, instead of being stored and used on a frequency basis, each threshold parameter can only be used on a per cell basis. Figure 6 illustrates this example. In step 602, the MS is provisionally housed in the server cell. The MS can first receive a list of cells neighboring the server cell (step 604). The MS can then decode certain reselection parameters from the list of neighboring cells broadcast by the server cell (step 606). The MS then identifies a candidate cell and performs measurements from it, such as signal strength, quality or power (step 608). If the cell does not meet the reselection requirements, the MS remains provisionally housed in the serving cell. If the candidate cell meets the reselection requirements (step 610), the MS proceeds to verify that it has any stored criteria available (step 612). If there are no stored criteria available in any way, the MS continues with the reselection process and tunes to the cell frequency to decode system information.
The MS then checks if there are any stored criteria available that were obtained from a cell having the same cell_ID as the candidate cell (step 614). If there are no applicable stored criteria, that is, none were obtained from a cell having the same cell_ID as the candidate cell, the MS continues with the reselection process and tunes to the frequency of the cell to decode system information.
The cell_ID can be the cell's mix code or it can be another cell identifier. The cell_ID does not have to be globally unique, but it can be unique locally. The identifier used to differentiate between cells in this particular example is an identifier that can be derived from the physical layer, that is, a physical layer identifier, such that the candidate cell can be identified without having to decode the cell's system information. Examples of such unique identifiers locally (which can be derived from the physical layer) include the 'physical layer cell identifier' of an E-UTRAN cell and the 'primary mixing code' of a UTRAN cell.
In this way, criteria can only be applied to the cell from which they were obtained. This removes the limitations of conventional reselection where an MS can be 'stuck' unnecessarily. Battery life is further minimized, when compared to known storage methods and where parameters are not stored, since an MS will not be tuning to the frequency of a cell several times to decode the parameters; since it is sufficient that they are stored and reused (for example, they can be reused if measurements change).
If the MS has stored criteria obtained from a cell having the same cell_ID as the candidate cell, the candidate cell is checked against these criteria (step 616), for example, using the measurements performed in step 608. If the test is successful , MS continues with the reselection process. If not, the MS remains provisionally housed in the server cell.
Optionally, before obtaining the candidate cell's system information to decode suitability parameters in step 618, it is not shown that the MS can evaluate the candidate cell using standard parameters that are not explicitly flagged. In one example, the default parameter is a predetermined quantity and is defined in the reselection specification. If the candidate cell does not meet the requirements based on this standard parameter, the MS does not continue with the reselection and the MS remains provisionally housed in the server cell. If the MS meets these requirements based on the standard parameter, the MS continues with the reselection process.
The MS then, if the conditions described above are met or not as may be the case, will tune to the frequency of the candidate cell and obtain system information (step 618). The suitability of the cell for reselection is then assessed based on decoded parameters from the system information (step 620). If the cell satisfies the suitability requirements (step 622), the MS can be temporarily housed in the cell (step 624). If not satisfied, the MS may remain provisionally housed in the server cell (step 602). The MS can maintain a list of cell parameters, in such a way that for each cell_ID the last decoded parameters are stored and replaced. Thus, each time stored criteria are used, it is very likely that they are as accurate as possible for that cell.
In an additional example, Closed Subscriber Group (CSG) cells can be treated differently from non-CSG cells. In the known algorithms there is no discrimination as for the parameters that can be applied to and recovered from these cells. In one embodiment, in a manner similar to that described previously, a parameter can be stored separately if it has been decoded from a CSG cell. This parameter can then only be applied to cells that are also CSG cells. In an additional example, stored CSG criteria can only be applied to candidate CSG cells operating at the same frequency as the cell from which the criteria were obtained. In addition, stored CSG criteria can only be applied to CSG candidate cells having the same cell ID from which the criteria were obtained. Thus, the fact that a CSG cell may have significantly different reselection criteria does not preclude reselection of a non-CSG cell; since CSG parameters are not stored and used against non-CSG cells and CSG parameters are applied only against CSG cells.
Figure 7 illustrates this example, where parameters are applied only to CSG cells only if they are derived from a CSG cell. In step 702, the MS is provisionally housed in the server cell. The MS can first receive a list of cells neighboring the server cell (step 704). The MS can then decode certain reselection parameters from the list of neighboring cells broadcast by the server cell (step 706). The MS then identifies a candidate cell and performs measurements of it, such as intensity, quality or signal strength (step 708). The candidate cell is a CSG cell. If the cell does not meet the reselection requirements, the MS remains provisionally housed in the serving cell. If the candidate cell meets the reselection requirements (step 710), the MS proceeds to verify that it has any stored criteria available (step 712). If they do not exist, the MS continues with the reselection process and tunes to the cell frequency to decode system information.
The MS then checks whether stored criteria that are available were obtained from a CSG cell, (step 714). If not, the MS continues with the reselection process and tunes to the cell's frequency to decode system information.
If the MS has stored criteria obtained from a CSG cell, the candidate CSG cell is checked against these criteria (step 716), for example, using the measurements performed in step 708. If the test is successful, the MS continues with the reselection process.
If not, the MS remains provisionally housed in the server cell.
The MS then, if the conditions described above are met or not as may be the case, will tune to the frequency of the candidate cell and obtain system information (step 718). The suitability of the cell for reselection is then assessed based on decoded parameters from the system information (step 720). If the cell satisfies the suitability requirements (step 722), the MS can be temporarily housed in the cell (step 724). If not satisfied, the MS may remain provisionally housed in the server cell (step 702).
Optionally, before obtaining the candidate cell's system information to decode suitability parameters in step 718, it is not shown that the MS can evaluate the candidate cell using standard parameters that are not explicitly flagged. In one example, the default parameter is a predetermined quantity and is defined in the reselection specification. If the candidate cell does not meet the requirements based on this standard parameter, the MS does not continue with the reselection and the MS remains provisionally housed in the server cell. If the MS meets these requirements based on the standard parameter, the MS continues with the reselection process.
Figure 8 illustrates a storage process in accordance with the present disclosure. In figure 8, the step of stopping the process if the cell is a CSG cell is applied only where CSG cell parameters are not stored or reused. Additionally, the step of deleting previously stored parameters is optional. Although this illustrates storage of CSG criteria, the illustration is also applicable for non-CSG cells storing specific frequency or identity parameters, so the criteria for storing the parameters are changed as required.
With the MS temporarily housed in a server cell (step 802), the MS can decode a cell's system information (step 804). The cell, referred to herein as 'cell A', may be a candidate cell that MS has previously evaluated, or it may be any other cell. In a known way, the MS can assess whether the cell from which the parameters are decoded, cell A, is from the same or an equivalent PLMN of the server cell (step 806). If it is not, the parameters may not be stored and the process may stop (step 806). If she does, the process can continue. This ensures that unnecessary parameters are not stored and the network may be able to control the configuration of the stored parameters. Then, according to the present example, the MS will check if the parameters are derived from a CSG cell (step 810). If they are, then the process will stop and the parameters will not be stored (step 812). This is just one example of the present revelation. Other examples are described in this document where the parameter is stored regardless of whether the non-CSG parameters and the CSG parameters are used only to evaluate CSG cells.
According to an example described earlier, the MS can then identify the frequency of the cell from which the parameters were derived (step 814). The decoded suitability criteria of the system information is then stored by the MS and associated with the frequency of the cell for subsequent use (step 816). Any previous parameters associated with the frequency of this cell, that is, F_A, can optionally be deleted (step 818). The process can then be completed (step 820). The storage process indicated above is equally applicable to the process of storing parameters in association with a unique cell identifier or any combination of the described criteria applicability.
In an additional example, it is considered that cells can broadcast a “do not store” signal to indicate that the MS should not store parameters for that cell. This can be useful, for example, for test cells, which can have very particular or unique configurations. Alternatively, there may be some implicit indication or definition of cells for which parameters should not be stored in any way; for example, one or more of the CSG cells as shown in Figure 8, barred cells or cells where a particular cause of waste has been received.
Stored values may also be subject to time controller expiration, to ensure that stored parameters (in particular, very restrictive parameters) complete the wait and do not permanently restrict reselection.
Replacement of stored values with more recently received values can also be restricted based on: - absolute value of encoded values - relative value to a previously stored value (greater / less than any difference).
This can be useful to prevent storage of obviously very restrictive parameters or unusual parameters, or to generally ensure that the most optimistic values are stored to prevent the device from incorrectly abandoning reselection assessment based on stored parameters.
The parameters stored by MS may have been obtained by means of reselection in idle mode or alternatively they may have been obtained in connected mode or by some other method. It is described that the parameters are obtained by decoding a cell's system information. This need not always be the case; for example, the parameters can be diffused separately from the system information. Other methods of obtaining and storing parameters in addition to those previously described are considered.
Figures 10 to 14 illustrate certain examples of the present disclosure. Certainly, it is considered that any of these examples described can be combined. Figure 10 illustrates an MS that first reads the System Information Block (SIB) of a first Cell 1 UTRAN. The Qrxlevmin parameter is stored in the MS and associated with the FREQ1 frequency of Cell 1 UTRAN where the parameters came from. The MS remains in the serving GSM cell, possibly because Cell 1 is not suitable for reselection; however, the reason is irrelevant. The MS then evaluates Cell 2 UTRAN for reselection. If the frequency of Cell 2 FREQ2 is equal to FREQ1, then the MS uses the stored Qrxlevmin value to evaluate Cell 2. It is not shown that, if the evaluation is successful, the MS will reselect to Cell 2, or alternatively the MS will continue or complete the reselection process for Cell 2 because it cannot be conclusive after this test that reselection will be successful. It is also not shown that if the frequencies are not equal, the evaluation is carried out without the stored parameter.
Figure 11 illustrates an MS that first reads the SIB of a first Cell 1 UTRAN. The Qrxlevmin parameter is stored in the MS and associated with the ID1 identity of Cell 1 UTRAN where the parameters came from. The ID1 identity, for example, can be the mix code. The MS remains in the serving GSM cell. The MS then evaluates Cell 2 UTRAN for reselection. If Cell_ID of Cell 2 ID2 is equal to ID1, then the MS uses the stored Qrxlevmin value to evaluate Cell 2. It is not shown that, if the evaluation is successful, the MS will reselect to Cell 2. It is also not shown that if the Cell_IDs are not the same, the evaluation is performed without the stored parameter.
Figure 12 illustrates an example of the present disclosure relating to CSG cells. The MS first decodes the System Information Block (SIB) of a first UTRAN cell. MS stores Qrxlevmin since the cell is a UTRAN cell and not a CSG cell. The MS then decodes the SIB of a CSG cell (which can also be a UTRAN cell). In this example, Qrxlevmin is not stored since the cell is a CSG cell. The MS then evaluates the UTRAN cell for reselection. MS uses the stored Qrxlevmin value obtained from the first UTRAN cell in the evaluation, since it was stored and the CSG cell Qrxlevmin was not.
Figure 13 illustrates another example of the present disclosure relating to CSG cells. The MS reads the SIB from a first CSG Cell 1 and decodes the SIB. The MS then stores the Qrxlevmin and associates it in its data store with an indication that the parameter was obtained from a CSG cell. The MS remains provisionally housed in the server cell, in this case a GSM cell. The MS then evaluates a second CSG Cell 2 for reselection using the stored Qrxlevmin value since Cell 2 is a CSG cell.
Figure 14 illustrates another example of the present disclosure. The MS is provisionally housed in a GSM cell. The MS reads and decodes the SIB of a first CSG Cell 1. The MS then stores the Qrxlevmin and associates it in the data store with an indication that the cell is a CSG Cell and with the Cell_ID of the cell, ID1, of which the Qrxlevmin is derived. The MS remains provisionally housed in the GSM Cell. The MS then evaluates a second CSG Cell 2 for reselection using the stored Qrxlevmin only if the cell is a CSG cell and the Cell_ID of the second cell, ID2, if it matches ID1. Preferably, the cell frequency and the Cell_ID can be considered together as described above; for example, the CSG cell can be evaluated using stored parameters only if the frequency and Cell_ID of the cell from which the parameters were obtained are the same as those for the candidate cell.
An exemplary specific implementation of an example of the present disclosure will now be described. In a system of multiple RATs, whenever the UE tries to temporarily host an FDD UTRAN cell (and / or is temporarily housed in the cell, and / or has any other reason to read the SIB of an FDD UTRAN cell) it decodes the RSCP criteria parameters of SIBs and stores them for future use. The UE can store the frequency of the cell in addition to other parameters. When a UE moves to 2G, the UE can start to apply the stored suitability criteria parameters for reselecting 2G to 3G cells for all UTRAN FDD cells configured on the frequency for which the last information was stored.
Currently, only the RSCP criterion is stored and used in the system, but with this change the UE needs to store the frequency associated with the RSCP criterion. The UE may have to maintain a list of frequencies and associated RSCP policy parameters. If the UE subsequently reads the SIB of another FDD UTRAN cell operating at a frequency for which it has stored suitability parameters, then it can replace the stored values with those of the SIBs that it has read exactly. The list will become clear after PLMN selection (see 3GPP TS 23.122).
The present disclosure reduces the chances of a device getting stuck in 2G in certain configurations, provides improved flexibility for operators when configuring suitability criteria (since these will only be used for other cells of the same frequency) and allows reselection of 2G cell to 3G for PLMN unrestricted frequencies in the case where certain frequencies are “restricted” by means of high suitability thresholds.
Considering the scenario of cells A, B and C described above, where cell B is the server cell, cell A is a cell whose parameters have been decoded previously and cell C is the current candidate cell, the parameters associated with Cell A can be: PLMN ID (referred to as PLMN_A) Frequency, [F_A] Physical layer address (PCI / PSC) [P_A] or Whether it is a CSG cell [isCSG_A].
These parameters can all be determined by decoding the system information (SIB) of cell A. The system information is generic and can be derived from blocks other than the SIB referred to throughout the present disclosure. The PLMN rules in these examples are merely exemplary and are not necessary for the present disclosure. They are an additional independent constraint.
The parameters associated with Cell B, which is the serving cell in this exemplary scenario, can be: PLMN ID, [PLMN_B]; or [Frequency, Physical layer address (PCI / PSC) which is relevant only if Cell B is the same RAT as Cells A, C].
The parameters associated with Cell C can be: Frequency, [F_C]; Physical layer address (PCI / PSC) [P_C]; If it is a CSG cell [isCSG_C] - This can only be determined based on F_C, or based on P_C and knowledge of the range of physical layer addresses reserved for CSG cells; or [PLMN_C which cannot be known at the time the initial radio signal quality / intensity assessment is performed].
Typically, conventional specifications state that Cell A parameters can be used to evaluate Cell C if PLMN_A = PLMN_B or PLMN_A and PLMN_B are equivalent.
One of the examples of the disclosure is to modify this rule so that Cell A parameters can be used to evaluate Cell C if i) PLMN_A = PLMN_B or PLMN_A and PLMN_B are equivalent and ii) F_A = F_C. Considering another example, illustrated in figure 8, considering CSG cells, this can be expressed as: Cell A parameters can be used to evaluate Cell C if i) PLMN_A = PLMN_B or PLMN_A and PLMN_B are equivalent, and ii) F_A = F_C, and iii) neither Cell A nor cell C are CSG cells (that is, isCSG_A = False and isCSG_C = False)
An additional example relating to CSG cells (which, in fact, reports that cells A and C must both be CSG cells), can be expressed as: Cell A parameters can be used to evaluate Cell C if i) PLMN_A = PLMN_B or PLMN_A and PLMN_B are equivalent, and ii) F_A = F_C, and iii) both Cell A and cell C are CSG cells (ie isCSG_A = True and isCSG_C = True) An additional example relating to CSG cells ( which, in fact, reports that cells A and C must, with high probability, be the same cell) can be expressed as the conditions indicated above in addition to: iv) P_A = P_C Additional modifications to the rules indicated above can be considered , to address the case where different (but equivalent) PLMNs have different reselection criteria, by modifying rule i) in each or any combination of the cases indicated above to: i) PLMN_A = PLMN_B
In a further example of the present disclosure, previously stored suitability requirements (which may have been obtained as a result of classification based reselection) should not be used when evaluating cells according to priority based reselection rules. In a priority-based reselection algorithm, threshold parameters can be diffused in the server cell, as previously described. In the present example, the restriction on the use of stored suitability parameters can be dependent on whether the corresponding parameters (signal quality / signal strength) are available in the current server cell, for example, broadcast by the cell. This is not always the case.
Figure 9 illustrates this particular example. The process can optionally start with an MS attempting to reselect to a 3G cell. The MS receives the Information Blocks from
3G cell system (SIBs) (step 904) and then decode and store the received signal code (RSCP) power criteria parameters (step 906). The MS can then evaluate a candidate 3G cell using the priority-based reselection rules in the known mode (step 908).
Conventionally, the MS will then evaluate the candidate cell against stored RSCP criteria (step 912) and, if the cell does not meet the criteria based on the stored RSCP parameters (step 914), the process will stop and the MS will not reselect to the cell ( step 916). If the candidate cell meets the criteria (step 914), then the cell will be evaluated to see if it meets the priority-based reselection criteria, as reported in section 6.6.6. of specification 45.008.
According to the present disclosure, however, the steps covered by the marked area 910 are not to be performed. According to the present disclosure, in a priority based reselection algorithm, the candidate cell is not to be evaluated using stored threshold criteria. These criteria may have been obtained as part of an algorithm based on classification and when decoding system information from another cell, or from the same cell.
In the present example, when the MS evaluates a candidate cell using the priority-based reselection rules (step 908), it then determines whether the candidate cell satisfies the priority-based reselection criteria in any way, or regardless of any stored parameters ( step 918). If the cell does not meet the criteria, the evaluation ends and the MS does not reselect to the cell (step 916). If the candidate cell meets the reselection criteria according to the priority-based reselection rules, the MS performs reselection to the cell (step 920).
In this way, the priority-based reselection algorithm is not obstructed by incorrect parameters, which may have been stored during classification-based reselection. If the parameters are spread across the server cell, they remain the primary criteria for use in priority-based reselection. If parameters are not broadcast, then the MS should determine the suitability of the cell for reselection without using stored parameters that may be unreliable.
Figure 15 illustrates an MS that first reads the System Information Block (SIB) of a UTRAN Cell while temporarily housed in a first GSM Cell 1. In Cell 1 GSM only classification algorithms are used for reselection for UTRAN cells. The Qrxlevmin parameter is stored in the MS. The MS can perform reselection of Cell 1 GSM to a second Cell 2 GSM. Cell 2 GSM supports priority based reselection. From GSM Cell 2, MS can evaluate the UTRAN cell using priority based reselection. When performing the priority-based assessment, the MS will not use the stored criteria that were obtained from the UTRAN cell during the classification algorithm. It is not shown that, if the evaluation is successful, the MS will reselect to the UTRAN Cell.
An exemplary algorithm that can be used to implement the principles of the previous disclosure will now be described. Although the language of the algorithm that this example builds can be altered or clarified, the principles illustrated by the text that has been inserted and altered when compared to those of the original algorithm are equally applicable to any amended algorithm.
This is an algorithm for cell reselection from GSM to UMTS based on cell classification. The algorithm in this sub-clause should be used for GSM to UMTS reselection if the conditions for using the cell reselection algorithm based on priority information are not satisfied.
If the 3G Cell Reselection list includes UTRAN frequencies, the MS must update the RLA_C value for the server cell and for each of the at least 6 strongest non-server GSM cells for at least every 5 s.
The MS must then reselect a suitable UTRAN cell (see 3GPP TS 25.304) if: - for a TDD cell the measured RSCP value is equal to or greater than TDD_Qoffset for a period of 5 s - for a FDD cell the following criteria are all met for a period of 5 s: 1. its measured RSCP value exceeds the RLA_C value for the server cell and all of the appropriate non-server GSM cells (see 3GPP TS 43.022) by the FDD_Qoffset value, 2. its measured Ec / No value is equal to or greater than the FDD_Qmin - FDD_Qmin_Offset value, and 3. its measured RSCP value is equal to or greater than FDD_RSCP_threshold.
In the event that a cell reselection occurs within the previous 15 seconds, FDD_Qoffset or TDD_Qoffset is increased by 5 dB. - Ec / No and RSCP are the measured quantities, see sub-clause 8.1.5. - FDD_RSCP_threshold equals FDD_RSCPmin - min ((P_MAX - 21 dBm), 3 dB) if FDD_RSCPmin is broadcast in the server cell, otherwise Qrxlevmin + Pcompensation + 10 dB, if these parameters are available, otherwise the default value of FDD_RSCPmin . - Qrxlevmin is the minimum required RX level in the FDD UTRAN cell (dBm), see 3GPP TS 25.304. - Pcompensation is max (UE_TXPWR_MAX_RACH - P_MAX, 0) (dB), see 3GPP TS 25.304. - UE_TXPWR_MAX_RACH is the maximum TX power level that an MS can use when accessing the FDD UTRAN cell in RACH (dBm), see 3GPP TS 25.304. - P_MAX is the maximum RF output power of the MS (dBm) in FDD UTRAN mode, see 3GPP TS 25.304. - FDD_Qmin, FDD_Qoffset and optionally FDD_RSCPmin and FDD_Qmin_Offset are broadcast in BCCH of the server cell. - TDD_Qoffset is broadcast in BCCH of the server cell. Note 1: The parameters required to determine if the UTRAN cell is suitable are broadcast in BCCH of the UTRAN cell. An MS can initiate reselection to the UTRAN cell before decoding the BCTR of the UTRAN cell, resulting in a small service interruption if the UTRAN cell is not suitable. Note 2: If FDD_RSCPmin is widespread, GSM reselection performance for optimal UTRAN is achieved if UTRAN cells in UTRAN coverage edge areas are planned for EU power of +24 dBm. Note 3: The TDD_Qoffset parameter is an absolute threshold for reselection for a target TDD UTRAN Cell.
The MS should store the UTRAN cell RSCP suitability criteria parameters indicated above, whenever decoded from an FDD UTRAN cell of an equivalent PLMN while attempting to temporarily host in the FDD UTRAN cell unless the cell is a CSG / indica cell 'not storing' / is inappropriate because {it is part of the “list of prohibited LAs for transfer between service areas”} or it is barred / or would result in an RSCP FDD threshold that is greater than that currently stored for cells on the same frequency / greater than [XX] dB. The most recently stored parameters of an FDD UTRAN cell of an equivalent PLMN are valid reselection criteria for all FDD UTRAN cells except CSG cells and cells evaluated according to the priority-based reselection algorithm (see sub-clauses 6.6.7 and 6.6 .6 respectively). Stored values that were received more than [5] minutes ago must be removed. This parameter list must be cleared after selecting PLMN (see 3GPP TS 23.122).
It should be noted that the "/" is used here to distinguish different aspects of the disclosure, although they can be combined.
Cell reselection to UTRAN should not occur within 5 seconds after the MS has reselected a GSM cell from a UTRAN cell if a suitable GSM cell can be found.
In the case of a reselection attempt for a barred UTRAN cell, the MS should abandon additional reselection attempt for this UTRAN cell as defined by the value Tbarrado in the barred UTRAN cell (see 3GPP TS 25.331).
In the event that the highest rated UTRAN cell is not suitable (see 3GPP TS 25.304) because of being on the “list of LAs prohibited for transfer between service areas” or belonging to a PLMN that is not indicated as being equivalent to the registered PLMN, the MS may abandon additional reselection attempt for this UTRAN cell and for all other cells at the same frequency, for a period of up to 20 min. If the MS has to perform cell selection, this limitation must be removed. If the MS is redirected under GERAN control to a frequency for which the time controller is running, any limitations on that frequency must be removed.
If more than one UTRAN cell meets the criteria indicated above, the MS must select the cell with the highest RSCP value.
An additional exemplary algorithm that can be used to implement the principles of the previous disclosure will now be described. Although the language of the algorithm that this example builds can be altered or clarified, the principles illustrated by the text that has been inserted and altered when compared to those of the original algorithm are equally applicable to any amended algorithm.
This is an algorithm for interRAT cell reselection based on priority information. The algorithm in this sub-clause should be used for interRAT cell reselection if priorities are available for the MS and thresholds are provided by the network, and if the mobile station supports priority-based inter-RAT cell reselection and priority information for the serving cell. provided by the network. A mobile station supporting E-UTRAN must support priority-based inter-RAT cell reselection for all supported RATs. A mobile station not supporting E-UTRAN and supporting UTRAN and supporting priority-based reselection from UTRAN to GERAN must support inter-RAT cell reselection based on priority to UTRAN.
The network must provide priority information if E-UTRAN frequencies are included in the list of neighboring cells; the network can provide priority information if only UTRAN frequencies are included in the list of neighboring cells. If priority information is available for the mobile station and the mobile station supports priority-based inter-RAT cell reselection, the algorithm in this sub-clause must be used for inter-RAT reselection for all RATs. The rules regarding which set of priorities are valid at any time are defined in 3GPP TS 44.018. NOTE 1: “Priority information” includes priorities and thresholds that are related to each UTRAN or E-UTRAN frequency (for example, UTRAN_PRIORITY, E- UTRAN_PRIORITY, THRESH_UTRAN_high, THRESH_E-UTRAN_high) and information related to the server cell (for example, GERAN_PRIORITY, THRESH_GSM_low). NOTE 2: Throughout the specification the phrase “list of neighboring cells” will also include the list of Neighboring Cells E-UTRAN where appropriate. NOTE 3: Priorities also need to be provided for network frequencies that do not support priority based cell reselection.
If the list of 3G Cell Reselections or the list of Neighboring Cells E-UTRAN includes frequencies from other radio access technologies, the MS must, at least every 5 s, update the RLA_C value for the server cell and each of the at least 6 stronger non-server GSM cells.
The MS must then reselect a suitable cell (see 3GPP TS 25.304 for UTRAN and 3GPP TS 36.304 for E-UTRAN) from another radio access technology if the following criteria are met. S_non-serving_XXX is the measurement quantity of a non-server inter-RAT cell and XXX indicates the other radio access technology / mode and is defined as follows: - for a UTRAN cell, it is the RSCP value measured for the least cell UTRAN_QRXLEVMIN for the cell frequency; - for an E-UTRAN cell, it is the RSRP value measured for the cell minus E-UTRAN_QRXLEVMIN for the cell frequency if THRESH_E-UTRAN_high_Q is not provided; otherwise, if THRESH_E-UTRAN_high_Q is given, it is the RSRQ value measured for the cell minus E-UTRAN_QQUALMIN for the cell frequency.
Stored suitability requirements (for example, such stored RSCP suitability requirements as specified in sub-clause 6.6.5) should not be used for UTRAN cells when evaluating cells according to the criteria in this sub-clause.
For a GSM cell, S_GSM is defined as the C1 value for the cell (see subclause 6.4);
Cell reselection to a cell from another inter-RAT frequency must be performed if any of the following conditions (to be evaluated in the order shown) are met: - The S_non-serving_XXX of one or more cells from an inter-RAT frequency higher priority is greater than THRESH_XXX_high (or, in the case of an E-UTRAN target, THRESH_E- UTRAN_high_Q, if provided) during a T_re-selection time interval; in that case the mobile station must consider the cells for reselection in decreasing order of priority and, for cells of the same inter-RAT frequency or of inter-RAT frequencies of equal priority, in decreasing order of S_non-serving_XXX, and reselect the first cell that satisfy the conditions indicated above; - The value of S_GSM is less than THRESH_GSM_low for the server cell and for all GSM cells measured during a time interval T_re-selection; in this case, the mobile station should consider inter-RAT cells for reselection in the following order, and reselect the first cell that meets the following criteria: - cells of a lower priority inter-RAT frequency whose S_non-serving_XXX is greater than THRESH_XXX_low ( or, in the case of an E-UTRAN target, THRESH_E- UTRAN_low_Q, if provided) for a period of time T re-selection; these cells must be considered in decreasing order of priority and, for cells of the same RAT, in decreasing order of S_non-serving_XXX; - if cells do not meet the criteria indicated above, inter-RAT cells for which, during a T_re-selection time interval, S_non-serving_XXX is greater than S_GSM for the server cell by at least one specific H_PRIO hysteresis; these cells should be considered in decreasing order of S_non-serving_XXX.
An FDD UTRAN cell should be reselected only if, in addition to the above criteria, its measured Ec / No value is equal to or greater than FDD_Qmin-FDD_Qmin_Offset.
If E-UTRAN_Qmin is provided for an E-UTRAN frequency, an E-UTRAN cell at that frequency should be reselected only if, in addition to the criteria indicated above, its measured RSRQ value is equal to or greater than E-UTRAN_Qmin. A mobile station must store {all / related RSRQ} suitability requirements for an E-UTRAN cell in the same PLMN or an equivalent PLMN such as that of the serving cell, [for which it has attempted reselection] [unless it has received an indication of that cell, for example, in system information that suitability requirements for that cell should not be stored] [the cell was a CSG cell] [or was not suitable]. When evaluating an E-UTRAN cell, the most recently stored RSRQ-related fitness requirements received from an E-UTRAN cell [other than those obtained from a CSG cell] at the same frequency / frequency of the same priority should be used if E-UTRAN_Qmin is not provided by the server cell.
If THRESH_E-UTRAN_high_Q is provided for an E-UTRAN frequency, and if E-UTRAN_RSRPmin is provided, an E-UTRAN cell at that frequency should only be reselected if, in addition to the criteria indicated above, its measured RSRP value is equal to or greater than E -UTRAN_RSRPmin. If E-UTRAN_RSRPmin is not provided, the default value must be used.
E-UTRAN cells that are included in the list of disallowed cells should not be considered as candidates for cell reselection. If the strongest cells on an E-UTRAN frequency are included in the list of disallowed cells, the mobile station can reselect the strongest valid cell (see sub-clause 8.4.7) on that frequency.
Cell reselection to a cell from another radio access technology (for example, UTRAN or E-UTRAN) should not occur within 5 seconds after the MS has reselected a GSM cell from an inter-RAT cell if a suitable GSM cell can be found.
If the mobile station applies common priorities or individual priorities received through dedicated signaling and if priorities are only available for some inter-RAT frequencies, cells belonging to frequencies for which no priority is not available or no threshold is not provided by the server cell they should not be considered for measurement and cell reselection.
If a mobile station in a normally housed state (see 3GPP TS 43.022) applies individual priorities received through dedicated signaling and no priority is not available to the serving cell, the mobile station must consider any GSM cell (including the cell server) to have a lower priority (that is, less than the eight values configured per network).
A mobile station in a state provisionally housed in any cell (see 3GPP TS 43.022) must ignore individual priorities received through dedicated signaling and must apply priorities received from the server cell's system information while trying to discover a suitable cell. If the mobile station supports CS voice services, the MS should avoid reselecting acceptable (but not suitable) E-UTRA cells regardless of the priorities provided in system information. NOTE 4: If the MS is temporarily staying in an acceptable cell, individual priorities are not discarded until an event resulting in their elimination occurs.
In the case of a reselection attempt for a barred UTRAN cell, the MS should abandon additional reselection attempt for this UTRAN cell as defined by the value Tbarrado in the barred UTRAN cell (see 3GPP TS 25.331).
In the case of a reselection attempt for a barred E-UTRAN cell, the MS should abandon an additional reselection attempt for this E-UTRAN cell for a period of up to 20 min.
In case the MS tries to reselect to an UTRAN cell that is not suitable (see 3GPP TS 25.304) because of being part of the “list of LAs prohibited for transfer between service areas” or belonging to a PLMN that is not indicated as being equivalent to the registered PLMN, the MS may abandon an additional reselection attempt for this UTRAN cell and for all other cells at the same frequency, for a period of up to 20 min. If the MS has to perform cell selection, this limitation must be removed. If the MS is redirected under GERAN control to a frequency for which the time controller is running, any limitations on that frequency must be removed.
In case the MS tries to reselect to an E-UTRAN cell that is not suitable (see 3GPP TS 36.304) because it is part of the “list of prohibited tracking areas for transfer between service areas” (see 3GPP TS 24.301), and if the MS has received the PCID for the TA Mapping information element (see 3GPP TS 44.018 and 3GPP TS 44.060) for the cell frequency, it should abandon additional reselection attempt for this E-UTRAN cell and for any E- cell UTRAN that is known to belong to the same Tracking Area until the PCID for the TA Mapping information changes in the server cell or until cell reselection occurs. If the mobile station has not received the PCID for the TA Mapping information element for the cell frequency, the MS may abandon additional reselection attempt for this E-UTRAN cell and for all other cells on the same frequency, for a period up to 20 min. If the MS has to perform cell selection, this limitation must be removed. If the MS is redirected under GERAN control to a frequency for which the time controller is running, any limitations on that frequency must be removed.
In the event that the MS attempts to reselect to an E-UTRAN cell that is not suitable (see 3GPP TS 36.304) because it belongs to a PLMN that is not indicated as being equivalent to the registered PLMN, the MS may abandon additional reselection attempt for this E-UTRAN cell and for all other cells at the same frequency, for a period of up to 20 min. If the MS has to perform cell selection, this limitation must be removed. If the MS is redirected under GERAN control to a frequency for which the time controller is running, any limitations on that frequency must be removed.
An additional exemplary algorithm that can be used to implement the principles of the previous disclosure will now be described. Although the language of the algorithm that this example builds can be altered or clarified, the principles illustrated by the text that has been inserted and altered when compared to those of the original algorithm are equally applicable to any amended algorithm.
This is an algorithm for cell selection and reselection for CSG cells and hybrid cells. First, for cell reselection to CSG cells, if a mobile station is a member of at least one Closed Subscriber Group, that is, at least one CSG ID is included in the MS CSG White List, then, in addition to cell reselection normal, the MS should use an autonomous search function to detect CSG UTRAN and / or E-UTRAN cells. The standalone search function should detect at least previously allowed CSG cells visited, according to performance requirements. NOTE 1: The standalone search function is implementation dependent and controls when and / or where to search for allowed CSG cells. NOTE 1a: (empty). NOTE 2: (empty). NOTE 3: (empty).
If the strongest cell (see 3GPP TS 25.304 and 3GPP TS 36.304 for the definition of the strongest cell) that the MS has detected on a UTRAN or E-UTRAN frequency during a T_re-selection time interval is a suitable CSG cell (see 3GPP TS 25.304 and 3GPP TS 36.304 for suitability criteria for CSG UTRAN and E-UTRAN cells respectively), it must reselect for this cell regardless of the cell reselection rules applicable to the cell in which the MS is currently provisionally housed.
The MS should disable the autonomous search function for CSG cells if the MS does not have a CSG White List or the MS CSG White List is empty.
When the MS does not have a CSG White List or it is empty, and the MS has stored "PSC CSG Division Information" or "PCI CSG Division Information", the MS should ignore cell measurement and reselection of cells known to be CSG cells , that is: - cells in a UTRAN frequency with PSC in the stored range “PSC CSG Division Information” for that frequency (see 3GPP TS 25.331); - cells on an E-UTRAN frequency with PCI in the stored range “PCI CSG Division Information” for that frequency (see 3GPP TS 36.331).
Furthermore, when the MS does not have a CSG White List or it is empty, the MS can ignore cells known as CSG cells for measurement and cell reselection according to specific implementation features at a frequency for which no “Information PCI CSG Division Information ”or“ PSC CSG Division Information ”is not stored.
The network can provide information regarding dedicated CSG UTRAN frequencies and / or dedicated CSG E-UTRAN frequencies. In this case, the MS can use the autonomous search function only on these dedicated frequencies and on the other frequencies listed in the system information. When the MS does not have a CSG White List or it is empty, the MS should ignore these frequencies for measurement and cell reselection.
A mobile station should store the fitness requirements related to RSRP / RSCP / RSRQ [ie, signal quality and / or signal strength] received from a CSG cell; these must be maintained regardless of stored criteria for non-CSG cells. When evaluating a CSG cell, the mobile station must use the most recently stored values of a cell [CSG] at the same frequency / with the CSG ID. Or when evaluating a CSG cell, the mobile station should use the stored values from the same cell (or from a cell with the same frequency and PCI / PSC) as long as they were received less than [2] minutes ago.
Second, for cell reselection for hybrid cells, if a mobile station is a member of at least one Closed Subscriber Group then, in addition to normal cell reselection, the MS must use an autonomous search function to detect hybrid cells. The standalone search function should detect at least previously visited hybrid cells whose CSG IDs are included in the MS CSG white list, according to performance requirements. NOTE: Standalone search for hybrid cells does not imply that MS needs to constantly check the CSG IDs of all cells it searches for, and the impact on battery consumption must be minimized.
If a neighboring cell has been detected as a hybrid cell and the CSG ID of the hybrid cell is included in the MS CSG White List, reselection for that cell must follow the rules for CSG cells in subclause 6.6.7.1. Otherwise normal cell reselection rules must be applied.
Third, for manual CSG ID selection, if NAS requests AS to search for available CSG IDs, MS must perform the search and disclose the results for NAS as described in 3GPP TS 25.304 for UTRAN and as described in 3GPP TS 36,304 for E-UTRAN. If a CSG ID is selected manually by NAS, the MS must proceed as specified in 3GPP TS 25.304 or 3GPP TS 36.304, depending on the RAT type of the selected CSG cell.
A further example of the present disclosure will now be described.
In some cases, as part of the typically known reselection algorithm, the device is required to evaluate one or more aspects of the target cell (such as signal quality or signal strength, etc.) based on parameters such as thresholds spread by the server cell (in this exemplary scenario, cell B).
However, he is currently required to reevaluate these aspects since he has to read the candidate cell's system information (cell C) as part of the suitability check (since the suitability criteria include tests based on parameters spread by the cell candidate). This results in the device evaluating the same aspects twice. In a well-configured network, the parameters must be such that a cell that meets the reselection criteria (based on parameters broadcast in the server cell) must not fail the corresponding tests based on broadcast parameters in the candidate cell. In this scenario, the second test is redundant.
However, and in addition, if the device performs both evaluations and fails the second test (that is, based on parameters broadcast in candidate cell C), it will return to the server cell. He can then repeat this process endlessly until cell C no longer meets the criteria based on the parameters broadcast by cell B. This is probably an incorrect network configuration. In this scenario, the second test may result in the mobile station attempting to repeatedly reselect to the same cell.
Storing and reusing parameters from cell A or C can address this last problem, however, no provision is currently made in the priority-based reselection scheme for storing criteria from a candidate cell (see 6.6.6 of 45.008).
In addition, as noted elsewhere, storing the suitability criteria disseminated by cell C in this scenario may cause an incorrect abandonment of attempted reselection to other cells (ie, except cell C), since it is likely a problem here is that cell C suitability criteria (such as determined based on parameters transmitted by cell C) are set incorrectly in such a way that the criteria are too high.
In an additional exemplary implementation of the disclosure, it would be preferable for the device not to perform one or any tests (for example, as part of the suitability test) based on criteria spread by cell C, if the criteria for reselection based on parameters spread on the server cell have already been tested and satisfied. If reselection criteria are met and the subset of suitability criteria is met, the device may remain provisionally housed in the candidate cell, regardless of the value (s) of the parameter (s) associated with the verification (s) (s) of ignored suitability (s) widespread in the candidate cell. This process is illustrated in figure 16.
As an additional exemplary implementation: it should omit only those suitability tests that assess specific aspects (signal strength, signal quality) that have been tested as part of the reselection procedure. In some cases, only one of signal strength / quality can be tested as part of the reselection algorithm.
Also as an additional exemplary implementation, it should omit only those tests that evaluate specific aspects (signal strength, signal quality) that were tested as part of the reselection procedure and that were based on parameters that were broadcast or transmitted by the server cell (such as as opposed to using standard normalized values).
As an additional exemplary implementation, the exception indicated above may only apply to “threshold-based” tests (that is, where a measured quantity of the candidate cell must meet or exceed some determined absolute value), but not to “relative value tests” ”- for example, where a measured value must exceed some other measured value (from the candidate cell, server cell and / or one or more other cells) by some minimal difference.
In an exemplary scenario of the last exemplary implementation, for CSG cells, a candidate CSG cell can satisfy the reselection criteria if it is the strongest in its frequency. This is considered a ‘relative’ test of signal strength, rather than an absolute test.
In typical conventional networks, where a device may currently be required to check suitability criteria twice: once using stored values (obtained from the same or a different cell), and once using values received from the candidate cell once it has decoded the relevant system information.
Currently, there is a relatively high risk that the suitability parameters stored by the device and used for the initial suitability assessment (that is, before information from the candidate cell system has been received) may be different from those disseminated by the candidate cell itself. . Therefore, it is reasonably possible that the suitability criteria can be satisfied in relation to the first test, but not for the second.
In an additional exemplary implementation of the disclosure that is illustrated in figure 16, if a restriction on the use of stored parameters of cell A when evaluating cell C is applied (such as, they must be on the same frequency, or both must be non-cells CSG), then the risk that the parameters are different is significantly reduced. Therefore, according to this exemplary implementation of the disclosure, to further reduce the need for parameter evaluation and / or to reduce the risk that a device determines (based on stored parameters) to perform reselection, it obtains system information from the candidate cell, and then determines that reselection is not possible. The device can omit the second suitability check. This is similar to the omission in the previous exemplary implementation of the disclosure.
This can be conditional on the frequency of cell A and cell C being the same; optionally, additional criteria may apply - such as cell A and cell C physical layer addresses must be the same; in general, any suitable criteria can be used, such as those listed above.
An additional condition may be that cell A and cell C are both candidates for reselection while the device is initially provisionally housed in cell B - for example, in the following case: i) device is provisionally housed in cell B; ii) device attempts to reselect cell A; reads suitability criteria for cell A and determines that they are not satisfied; remains in cell B; iii) device tries to reselect to cell C - cell C and cell A operate at the same frequency; cell C meets the suitability criteria as obtained from cell A; device does not reevaluate suitability criteria based on parameters obtained from cell C. (In other words, the device is temporarily housed in cell C regardless of the suitability parameters signaled by cell C).
It is worth noting that if operators coordinate the configuration of cell suitability parameters through a PLMN server and equivalent PLMNs to the point that these parameters are similar across all cells, then this solution can be applicable even without any restrictions in cell A and in cell C.
In figure 16, the illustrated process starts with the MS provisionally housed in a server cell, cell B (step 1602). The MS can then optionally receive a list of cells neighboring the server cell (step 1604). The MS then decodes the list's reselection parameters (step 1606). The MS will then identify a candidate cell and perform measurements on it (step 1608). If the cell does not meet reselection criteria, the MS remains provisionally housed in the serving cell (step 1610). If the criteria are met, the MS checks whether it has stored suitability parameters available (step 1612). If the MS has stored suitability parameters available, the MS checks the cell against these criteria (step 1614). If the criteria are not met, the MS remains provisionally housed in the server cell. If the criteria are met or if the MS has no parameters stored and available for testing, the MS changes to obtain system information from the candidate cell (step 1616).
After obtaining system information, the MS considers radio-related aspects such as signal strength or quality (step 1618). If these were assessed when determining whether the cell met the reselection criteria (step 1620) and the assessment was not based on standard parameters that were not explicitly flagged (step 1622) then the MS changes to check for another radio related aspect (step 1626 ). If there are no more aspects, then the cell is determined to satisfy the criteria (step 1632) and non-radio related criteria are evaluated (step 1634). Thus, if flagged criteria were used and verified against radio related aspects then MS does not again determine suitability.
If radio related aspects were not assessed when determining whether the cell met reselection criteria (step 1620) and if the assessment used stored suitability parameters (step 1624), then the MS changes to verify another radio related aspect (step 1624) 1626). If there are no more aspects, then the cell is determined to satisfy the criteria (step 1632) and non-radio related criteria are evaluated (step 1634). Thus, if flagged criteria were used and verified against radio related aspects then MS does not again determine suitability.
If radio related aspects were assessed when determining whether the cell met reselection criteria (step 1620) and the assessment was based on standard parameters that were not explicitly flagged (step 1622), then the MS checks whether the assessment used adequacy parameters stored (step 1624). If used, the MS changes to verify another aspect related to radio (step 1626). If there are no more aspects, then the cell is determined to satisfy the criteria (step 1632) and non-radio related criteria are evaluated (step 1634). Thus, if flagged criteria were used and verified against radio related aspects then MS does not again determine suitability.
If the MS did not use stored suitability parameters (step 1624), the MS evaluates the cell using parameters from the candidate cell's system information (step 1628), when establishing a communication channel and decoding the parameters. If the cell does not meet the criteria, it is determined to be unacceptable and the MS remains provisionally housed in the serving cell (step 1636). If it meets the criteria, the MS changes to verify another aspect related to radio (step 1626). If there are no more aspects, then the cell is determined to satisfy the criteria (step 1632) and non-radio related criteria are evaluated (step 1634). Thus, if flagged criteria were used and verified against radio related aspects then MS does not again determine suitability.
An exemplary algorithm for implementing examples of the present disclosure will now be described. This is an algorithm for inter-RAT cell reselection based on priority information.
The algorithm in this sub-clause should be used for inter-RAT cell reselection if priorities are available for the MS and thresholds are provided by the network, and if the mobile station supports inter-RAT cell reselection based on priority and priority information for the cell server is provided by the network. A mobile station supporting E-UTRAN must support priority-based inter-RAT cell reselection for all supported RATs. A mobile station not supporting E-UTRAN and supporting UTRAN and supporting priority-based reselection from UTRAN to GERAN must support inter-RAT cell reselection based on priority to UTRAN.
The network must provide priority information if E-UTRAN frequencies are included in the list of neighboring cells; the network can provide priority information if only UTRAN frequencies are included in the list of neighboring cells. If priority information is available for the mobile station and the mobile station supports priority-based inter-RAT cell reselection, the algorithm in this sub-clause must be used for inter-RAT reselection for all RATs. The rules regarding which set of priorities are valid at any time are defined in 3GPP TS 44.018. NOTE 1: “Priority information” includes priorities and thresholds that are related to each UTRAN or E-UTRAN frequency (for example, UTRAN_PRIORITY, E- UTRAN_PRIORITY, THRESH_ UTRAN_high, THRESH_E-UTRAN_high) and information related to the server cell (for example , GERAN_PRIORITY, THRESH_GSM_low). NOTE 2: Throughout the specification, the phrase “list of neighboring cells” will also include the list of Neighboring Cells E-UTRAN where appropriate. NOTE 3: Priorities also need to be provided for network frequencies that do not support priority based cell reselection.
If the list of 3G Cell Reselections or the list of Neighboring Cells E-UTRAN includes frequencies from other radio access technologies, the MS must, at least every 5 s, update the RLA_C value for the server cell and for each one at least 6 strongest non-server GSM cells.
The MS must then reselect a suitable cell from another radio access technology if the following criteria are met. S_non-serving_XXX is the measurement quantity of a non-server inter-RAT cell and XXX indicates the other radio access technology / mode and is defined as follows: - for a UTRAN cell, it is the RSCP value measured for the least cell UTRAN_QRXLEVMIN for the cell frequency; - for an E-UTRAN cell, it is the RSRP value measured for the cell minus E-UTRAN_QRXLEVMIN for the cell frequency if THRESH_E-UTRAN_high_Q is not provided; otherwise, if THRESH_E-UTRAN_high_Q is given, it is the RSRQ value measured for the cell minus E-UTRAN_QQUALMIN for the cell frequency.
For a GSM cell, S_GSM is defined as the C1 value for the cell (see subclause 6.4);
The definition of a suitable cell is specified in 3GPP TS 25.304 for UTRAN and 3GPP TS 36.304 for E-UTRAN. However, for the purposes of cell reselection, the suitability requirements related to signal strength (signal quality correspondingly) do not need to be assessed (ie the cell can be considered adequate even if it does not meet the requirements for signal strength. (signal quality correspondingly) as specified in the fit definition, using parameters obtained from the candidate cell's system information) if: - or: - signal strength (signal quality correspondingly) has been evaluated as part of the reselection algorithm, and - the corresponding parameters used in the reselection algorithm (for example, for FDD UMTS signal quality, FDD_Qmin, FDD_Qmin_Offset: for UMTS signal strength, UTRAN_QRXLEVMIN) were explicitly flagged in the server cell (that is, standard values were not used) - or : - the cell meets the suitability criteria for signal strength (signal quality correspondingly ) based on stored parameters that were received from a cell operating using the same radio access technology and on the same frequency.
It should be noted and understood that the list of corresponding parameters indicated above is not exhaustive. The disclosure applies where some specified part or all parameters must be flagged explicitly and not default values.
Cell reselection to a cell from another inter-RAT frequency must be performed if any of the following conditions (to be evaluated in the order shown) are met: - The S_non-serving_XXX of one or more cells from an inter-RAT frequency higher priority is greater than THRESH_XXX_high (or, in the case of an E-UTRAN target, THRESH_E- UTRAN_high_Q, if provided) during a T_re-selection time interval; in that case the mobile station must consider the cells for reselection in decreasing order of priority and, for cells of the same inter-RAT frequency or of inter-RAT frequencies of equal priority, in decreasing order of S_non-serving_XXX, and reselect the first cell that satisfy the conditions indicated above; - the value of S_GSM is less than THRESH_GSM_low for the server cell and for all GSM cells measured during a T_re-selection time interval; in this case, the mobile station should consider inter-RAT cells for reselection in the following order, and reselect the first cell that meets the following criteria: - cells of a lower priority inter-RAT frequency whose S_non-serving_XXX is greater than THRESH_XXX_low ( or, in the case of an E-UTRAN target, THRESH_E-UTRAN_low_Q, if provided) during a T_re-selection time interval; these cells must be considered in decreasing order of priority and for cells of the same RAT in decreasing order of S_non-serving_XXX; - if cells do not meet the above criteria, inter-RAT cells for which, during a time interval T_re-selection, S_non-serving_XXX is greater than S_GSM for the server cell by at least one specific H_PRIO hysteresis; these cells should be considered in decreasing order of S_non-serving_XXX.
A FDD UTRAN cell should be reselected only if, in addition to the criteria indicated above, its measured Ec / No value is equal to or greater than FDD_Qmin - FDD_Qmin_Offset.
If E-UTRAN_Qmin is provided for an E-UTRAN frequency, an E-UTRAN cell at that frequency should be reselected only if, in addition to the criteria indicated above, its measured RSRQ value is equal to or greater than E-UTRAN_Qmin.
If THRESH_E-UTRAN_high_Q is provided for an E-UTRAN frequency, and if E-UTRAN_RSRPmin is provided, an E-UTRAN cell on that frequency should only be reselected if, in addition to the criteria indicated above, its measured RSRP value is equal to or greater than E -UTRAN_RSRPmin. If E-UTRAN_RSRPmin is not provided, the default value must be used.
E-UTRAN cells that are included in the list of disallowed cells should not be considered as candidates for cell reselection. If the strongest cells on an E-UTRAN frequency are included in the list of disallowed cells, the mobile station can reselect the strongest valid cell (see sub-clause 8.4.7) on that frequency.
Cell reselection to a cell from another radio access technology (for example, UTRAN or E-UTRAN) should not occur within 5 seconds after the MS has reselected a GSM cell from an inter-RAT cell if a suitable GSM cell can be discovered.
If the mobile station applies common priorities or individual priorities received through dedicated signaling and if priorities are only available for some inter-RAT frequencies, cells belonging to frequencies for which no priority is not available or no threshold is not provided by the server cell they should not be considered for measurement and cell reselection.
If a mobile station in a normally housed state (see 3GPP TS 43.022) applies individual priorities received through dedicated signaling and if no priority is not available for the server cell, the mobile station must consider any GSM cell (including the server cell) to have a lower priority (that is, less than the eight values configured per network).
A mobile station in a state provisionally housed in any cell (see 3GPP TS 43.022) must ignore individual priorities received through dedicated signaling and must apply priorities received from the server cell's system information while trying to discover a suitable cell. If the mobile station supports CS voice services, the MS should avoid reselecting acceptable (but not suitable) E-UTRA cells regardless of the priorities provided in system information.
NOTE 4: If the MS is temporarily staying in an acceptable cell, individual priorities are not discarded until an event resulting in their elimination occurs.
In the case of a reselection attempt for a barred UTRAN cell, the MS should abandon additional reselection attempt for this UTRAN cell as defined by the value Tbarrado in the barred UTRAN cell (see 3GPP TS 25.331).
In the case of a reselection attempt for a barred E-UTRAN cell, the MS should abandon an additional reselection attempt for this E-UTRAN cell for a period of up to 20 min.
In case the MS tries to reselect to an UTRAN cell that is not suitable (see 3GPP TS 25.304) because of being part of the “list of LAs prohibited for transfer between service areas” or belonging to a PLMN that is not indicated as being equivalent to the registered PLMN, the MS may abandon an additional reselection attempt for this UTRAN cell and for all other cells at the same frequency, for a period of up to 20 min. If the MS has to perform cell selection, this limitation must be removed. If the MS is redirected under GERAN control to a frequency for which the time controller is running, any limitations on that frequency must be removed.
In case the MS tries to reselect to an E-UTRAN cell that is not suitable (see 3GPP TS 36.304) because it is part of the “list of prohibited tracking areas for transfer between service areas” (see 3GPP TS 24.301), and if the MS has received the PCID for the TA Mapping information element (see 3GPP TS 44.018 and 3GPP TS 44.060) for the cell frequency, it should abandon additional reselection attempt for this E-UTRAN cell and for any E cell -UTRAN that is known to belong to the same Tracking Area until the PCID for the TA Mapping information changes in the server cell or until cell reselection occurs. If the mobile station has not received the PCID for the TA Mapping information element for the cell frequency, the MS may abandon additional reselection attempt for this E-UTRAN cell and for all other cells on the same frequency, for a period up to 20 min. If the MS has to perform cell selection, this limitation must be removed. If the MS is redirected under GERAN control to a frequency for which the time controller is running, any limitations on that frequency must be removed.
In the event that the MS attempts to reselect to an E-UTRAN cell that is not suitable (see 3GPP TS 36.304) because it belongs to a PLMN that is not indicated as being equivalent to the registered PLMN, the MS may abandon additional reselection attempt for this E-UTRAN cell and for all other cells at the same frequency, for a period of up to 20 min. If the MS has to perform cell selection, this limitation must be removed. If the MS is redirected under GERAN control to a frequency for which the time controller is running, any limitations on that frequency must be removed.
Although the present disclosure is primarily described in terms of methods, a person of ordinary skill in the art will understand that the present disclosure is also directed to various devices such as an electronic handheld device including components to perform at least some of the aspects and features of the methods described, either by means of hardware components, software or any combination of the two, or in any other way. In addition, an article of manufacture for use with the apparatus, such as a pre-recorded storage device or other similar computer-readable media including program instructions recorded on it, or a computer data signal carrying program instructions readable by computer can direct a device to facilitate the practice of the described methods. It is understood that such apparatus, articles of manufacture and computer data signals are also within the scope of the present disclosure.
The term “computer-readable media” as used in this document means any media that can store instructions for use or execution by a computer or other computing device including, but not limited to, a portable floppy disk, a disk drive hard drive (HDD), a random access memory (RAM), a read-only memory (ROM), a programmable and erasable read-only memory (EPROM) or flash memory, an optical disc such as a Compact Disc (CD), Digital Versatile Disc (DVD) or Blu-ray ™ Disc, and a solid state storage device (for example, NAND flash or synchronous dynamic RAM (SDRAM)).
Example embodiments of the present disclosure are not limited to any particular operating system, system architecture, mobile device architecture, server architecture or computer programming language.
The various modalities presented above are merely examples and variations of the innovations described in this document will be apparent to people of ordinary knowledge in the art. The modalities can be implemented in a variety of ways without deviating from their characteristics, and it should also be understood that the modalities described above are not limited by any of the details of the previous description, unless otherwise specified, but instead must be widely interpreted within its scope as defined in the appended claims. Therefore, various changes and modifications that fall within the scope of the claims, or equivalences of that scope, are therefore considered to be covered by the appended claims.
It is to be noted that the methods as described have actions performed in a particular order. However, it will be clear that the order of any actions taken, where the context allows, can be varied and so the ordering as described in this document is not proposed to be a limitation.
It is also to be noted that where a method has been described it is also intended that protection is also intended for a device arranged to perform the method and where resources have been claimed independently of each other these can be used in conjunction with other claimed resources.
In addition, it will be noted that the apparatus described in this document may comprise a single component such as a wireless telecommunications device or UTRAN or other user equipment or access network components, a combination of multiple such components, for example, in communication with each other or in a subnet or complete network of such components.
Modalities have been described here in relation to the 3GPP specifications. However, the method and apparatus described are not intended to be limited to the specifications or versions referred to in this document, but may be applicable to future versions or other specifications.
According to one aspect of the disclosure, a method performed by a device on a wireless network can be provided, the method comprising: storing a first cell parameter associated with a first cell characteristic; and determining the suitability of a second cell for reselection by the device, wherein, if the second cell has a characteristic in common with said feature of the first cell, it determines the reselection suitability of the second cell according to said stored parameter.
The method can also additionally comprise: deleting any previously stored parameters from the device associated with said characteristic of the first cell.
The characteristic of the first cell can be the carrier frequency of the first cell.
According to another aspect of the disclosure, a method performed by a device on a wireless network can be provided, the method comprising: determining network identification information of said first cell; determine a parameter of adequacy criteria for a second cell; determining network identification information of said second cell; and if said network identification information of said first cell is equal to or equivalent to said network identification information of said second cell, storing said parameter.
The method can also additionally comprise: after the procedure of storing said parameter, associate said stored parameter with a characteristic of the second cell and determine the suitability of a third cell for reselection by the device, in which, if the third cell has a characteristic of the third cell in common with said characteristic of the second cell associated with said stored parameter, determining the reselection suitability of the third cell according to said stored parameter.
The method can also additionally comprise: deleting any previously stored parameters from the device associated with said characteristic of the second cell.
According to another aspect of the disclosure, a method performed by a device on a wireless network can be provided, the method comprising: determining a second cell suitability criteria parameter; determining whether said second cell belongs to a closed group of subscribers; and if said second cell fails to belong to a closed group of subscribers, store said parameter.
The method can also additionally comprise: after the procedure of storing said parameter, associate said stored parameter with a characteristic of the second cell and determine the suitability of a third cell for reselection by the device, in which, if the third cell has a characteristic in common with said characteristic of the second cell associated with said stored parameter, determining the reselection suitability of the third cell according to said stored parameter.
The method can also additionally comprise: deleting any previously stored parameters from the device associated with said characteristic of the second cell.
According to another aspect of the disclosure, a device for use on a wireless network can be provided, the device comprising one or more processors; a wireless transceiver coupled to one or more processors; and memory coupled to one or more processors, the one or more processors being operative to: store a parameter of a first cell associated with a characteristic of the first cell; and determining the suitability of a second cell for reselection by the device, wherein, if the second cell has a feature in common with said feature of the first cell, the reselection suitability of the second cell is determined according to said stored parameter.
The device can be operative additionally to: delete from the device any previously stored parameters associated with said characteristic of the first cell.
The characteristic of the first cell can also be the carrier frequency of the first cell.
According to another aspect of the disclosure, a device is provided for use on a wireless network, the device comprising one or more processors; a wireless transceiver coupled to one or more processors; and memory coupled to one or more processors, the one or more processors being operative to: communicate with a first cell; determining network identification information from said first cell; determine a parameter of adequacy criteria for a second cell; determining network identification information of said second cell; and if said network identification information of said first cell is equal to said network identification information of said second cell, storing said parameter.
The device can be operative additionally for: after said parameter has been stored, associate said stored parameter with a characteristic of the second cell and determine the suitability of a third cell for reselection by the device, where, if the third cell has a characteristic in common with said characteristic of the second cell associated with said stored parameter, the reselection suitability of the third cell is determined according to said stored parameter.
The device can be operative additionally to: delete any previously stored parameters associated with said characteristic of the second cell.
According to another aspect of the disclosure, a device for use on a wireless network can be provided, the device comprising one or more processors; a wireless transceiver coupled to one or more processors; and memory coupled to one or more processors, the one or more processors being operative to: communicate with a first cell; determine a parameter of adequacy criteria for a second cell; determining whether said second cell belongs to a closed group of subscribers; and if said second cell fails to belong to a closed group of subscribers, store said parameter.
The device can be operative additionally for: after said parameter has been stored, associate said stored parameter with the characteristic of the second cell and determine the suitability of a third cell for reselection by the device, in which, if the third cell has a characteristic in common with said characteristic of the second cell associated with said stored parameter, the reselection suitability of the third cell is determined according to said stored parameter.
The device can be operative additionally to: delete any previously stored parameters associated with said characteristic of the second cell.
According to another aspect of the disclosure, a method performed by a device on a wireless network can be provided, the method comprising: determining a parameter from a first set of criteria, said criteria being reselection criteria, from a second cell , and if said parameter satisfies a predetermined condition: determining system information of said second cell; and determining the suitability of the second cell for reselection by the device using a second set of criteria, said second set of criteria being suitability criteria, in which if said suitability criteria contain the parameter included in said set of reselection criteria, determine suitability without re-determining said parameter for use in said suitability criteria.
The method can also further comprise: performing cell reselection for said second cell.
According to another aspect of the disclosure, a device for use on a wireless network can be provided, the device comprising one or more processors; a wireless transceiver coupled to one or more processors; and memory coupled to one or more processors, the one or more processors being operative to: determine a parameter of a first set of criteria, said criteria being reselection criteria, of a second cell, and if said parameter satisfies a predetermined condition : determining system information of said second cell; and determine the suitability of the second cell for reselection by the device using a second set of criteria, said second set of criteria being suitability criteria, in which if said suitability criteria contain the parameter included in said set of reselection criteria, the device being operative to determine suitability without again determining said parameter for use in said suitability criteria.
The method according to the first aspect can also further comprise: if the second cell is determined to be suitable according to said stored parameter, obtaining system information from the second cell.
The method according to the first aspect can also further comprise: if the second cell is determined to be unsuitable according to said stored parameter, omit to obtain system information from the second cell.
According to another aspect of the disclosure, a method performed by a device on a first cell of a radio access network can be provided, the method comprising evaluating an aspect of a second cell against a reselection criterion, receiving information system of said second cell; and determining the suitability of said second cell without assessing said aspect in comparison to suitability criteria using parameters received in said system information.
The method can also further comprise: performing cell reselection for said second cell.
According to another aspect of the disclosure, a method performed by a device on a first cell of a radio access network can be provided, the method comprising evaluating an aspect of a second cell against a stored suitability criterion, receiving system information of said second cell; and determining the suitability of said second cell without assessing said aspect in comparison to suitability criteria using parameters received in said system information.
The method can also further comprise: performing cell reselection for said second cell.
In addition, the characteristic of the second cell can be determined by reference to one or more aspects of the physical layer, alone or in combination with data stored in the UE.

权利要求:
Claims (13)
[0001]
1. Method in a wireless cellular telecommunications device housed in a server cell, the device storing a parameter obtained by decoding system information from a first cell (906), the method characterized by the fact that it comprises: measuring an attribute of a signal received from a candidate cell; and evaluating the candidate cell for reselection based on the measured attribute (918) according to a reselection algorithm based on priority independent of the stored parameter, where the stored parameter indicates a minimum required received signal code strength.
[0002]
2. Method, according to claim 1, characterized by the fact that it still comprises performing reselection of the serving cell to the candidate cell based on the evaluation (920).
[0003]
3. Method according to claim 1 or 2, characterized by the fact that the evaluation of the candidate cell includes: obtaining system information from the candidate cell, the system information including a candidate cell parameter (904); determine if the measured attribute exceeds the candidate cell parameter by a predetermined quantity (914), and if the measured attribute exceeds the candidate cell parameter by a predetermined quantity, perform reselection to the candidate cell (920).
[0004]
4. Method according to claim 3, characterized by the fact that the predetermined amount is 0 dB.
[0005]
5. Method according to any one of claims 1 to 4, characterized by the fact that the evaluation of the candidate cell for reselection includes: determining whether the measured attribute exceeds a predetermined standard value, and whether the measured attribute is insufficient to exceed the predetermined default value, determining that the candidate cell does not meet reselection requirements.
[0006]
6. Method according to any one of claims 1 to 5, characterized by the fact that the measured attribute is received signal code power, RSCP.
[0007]
Method according to any one of claims 1 to 6, characterized in that the candidate cell is a UTRAN cell.
[0008]
Method according to any one of claims 1 to 7, characterized in that the serving cell is a GERAN cell.
[0009]
Method according to any one of claims 1 to 8, characterized by the fact that it further comprises: measuring an attribute of a signal received from a second cell; and evaluate the second cell for reselection based on the measured attribute and the stored parameter according to a classification algorithm.
[0010]
10. Method according to any one of claims 1 to 9, characterized by the fact that the server and candidate cells are from the same wireless radio network.
[0011]
11. Method according to any one of claims 1 to 9, characterized in that the serving and candidate cell are from different wireless radio networks.
[0012]
12. Wireless cellular telecommunications device, characterized by the fact that it is adapted to: be housed in a server cell; storing a parameter obtained by decoding system information from a first cell, and executing the method as defined in any one of claims 1 to 11.
[0013]
13. Computer-readable storage media, characterized by the fact that it has stored instructions 15 that can be executed by a device to perform the actions as defined in any of claims 1 to 11.

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WO2012072714A1|2012-06-07|

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AU2011334952B2|2015-06-11|

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JP2013544477A|2013-12-12|

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CA2819280A1|2012-06-07|

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HK1171146A1|2013-03-15|

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AU2011334952A8|2016-07-07|

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KR20130098422A|2013-09-04|

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CN103238352B|2017-02-08|

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法律状态:
2018-01-02| B25D| Requested change of name of applicant approved|Owner name: BLACKBERRY LIMITED (CA) |

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2018-01-23| B25G| Requested change of headquarter approved|Owner name: BLACKBERRY LIMITED (CA) |

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2018-12-18| B06F| Objections, documents and/or translations needed after an examination request according [chapter 6.6 patent gazette]|

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2020-04-28| B06U| Preliminary requirement: requests with searches performed by other patent offices: procedure suspended [chapter 6.21 patent gazette]|

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2020-12-08| B09A| Decision: intention to grant [chapter 9.1 patent gazette]|

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2021-02-23| B16A| Patent or certificate of addition of invention granted|Free format text: PRAZO DE VALIDADE: 20 (VINTE) ANOS CONTADOS A PARTIR DE 30/11/2011, OBSERVADAS AS CONDICOES LEGAIS. |

优先权:

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申请号 | 申请日 | 专利标题

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US41832210P| true| 2010-11-30|2010-11-30|

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US61/418,322|2010-11-30|

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PCT/EP2011/071445|WO2012072714A1|2010-11-30|2011-11-30|Cell re-selection in a cellular telecommunications network|

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