RADIO LINK FAILURE (RLF) DETECTION FOR RECOVERY

专利摘要:
radio link failure detection (rlf) for recovery the presented embodiments refer to a method in a user equipment (10) for handling a radio link failure in a radio communication network. the user equipment (10) is served in a first cell (14) controlled by a radio base station (12), and which base station (12) is comprised in the radio communication network. the user equipment (10) detects a first indication of a radio link failure between the user equipment (10) and the base station (12). the user equipment (10) then transmits a second radio link failure indication to the base station (12) when the first indication is detected.
公开号:BR112012020879B1
申请号:R112012020879-9
申请日:2010-12-23
公开日:2021-06-15
发明作者:Konstantinos Dimou；Magnus Stattin；Wei Zhao
申请人:Guangdong Oppo Mobile Telecommunications Corp., Ltd；
IPC主号:

专利说明:

technical field
Embodiments presented here refer to user equipment, a base station and methods concerned. In particular, such embodiments relate to enabling the user equipment to establish a connection in a radio communication network. Fundamentals
In today's radio communication networks, several different technologies are used, such as Long Term Evolution (LTE), LTE-Advanced, 3rd Generation Partnership Project (3GPP), Wideband Code Division Multiple Access (WCDMA) System, Global System for Mobile communications/Enhanced Data rate for GSM Evolution (GSM/EDGE), World ide Interoperability for Microwave Access (WiMax), or Ultra Mobile Broadband (UMB), just to name a few. A radio communication network comprises radio base stations providing radio coverage over at least a respective geographic area forming a cell. User equipment (EU) are serviced in the cells by the respective base station and communicate with the respective base station. User equipment transmits data over an air interface to radio base stations in uplink (UL) transmissions and radio base stations transmit data to user equipment in downlink (DL) transmissions. When user equipment moves from one cell to another, the user equipment connection or link has to be transferred in a process called handover (HO). In LTE, for example, an inter-cell frequency reuse is used, similar to WCDMA-based systems. However, in LTE, soft HO of cross-cell user equipment is not part of the standard specification and instead hard HO of cross-cell user equipment is adopted. Smooth transfer means that user equipment is connected to both cells simultaneously during the transfer procedure. Hard transfer means that a link to a source cell is released and then a link to the target cell is established. However, hard transfer is a procedure that can experience failures, such as radio link failures (RLF).
Typical scenarios in RLFs that can occur more frequently are the so-called: i) “high speed train” and ii) “Manhattan”. A high-speed train scenario is when user equipment is moving fast between cells, and a Manhattan scenario is when user equipment is moving between a large number of cells due to the corner effect. Corner effect means that user equipment can be serviced in one cell and, when turning a corner, a different cell can be in line of sight and the serviced cell may not have coverage around the corner, resulting in a cell shift very abrupt. In order to combat RLFs, within current LTE versions such as Release 8 and beyond, a mechanism that allows user equipment to recover from RLF has been defined.
The mechanism is called "RLF recovery" within 3GPP and comprises a process in which a radio link failure occurs during a one-time transfer, for example, and the procedure for its recovery involves acquiring synchronization with the cellular system again . Synchronization takes some time to run. The user equipment then selects a better cell in terms of signal strength measurement, such as Reference Signal Received Power (RSPR) or Reference Signal Received Power Quality (RSRQ) which are processes to indicate signal strength of reference signs. This also requires some time interval to run. The user equipment then performs a random access procedure which is also time consuming. The random access procedure is performed in order to establish a connection. Finally, the user equipment makes a Connection Re-establishment Request to the Radio Resource Control (RRC) and receives a completed RRC Re-establish Connection response, indicating that the reconnection is re-established.
Slow RLF recovery implies long outage time. The total duration of radio link failure recovery is dictated by a timer. In the event that user equipment does not receive an acknowledgment acknowledgment (ACK) such as an RRC Connection Reconfiguration Request ACK message from the network within a time period defined by the timer, then the RLF recovery procedure is determined to have failed and the user equipment switches from an active mode back to a standby mode. In this case, the RRC connection is lost and the user equipment needs to establish a new RRC connection. Simulations have shown that, in these challenging mobility scenarios, the total procedure takes 500-600ms for 90% of cases.
The amount of time to reestablish the RRC connection can increase the outage time. Prior art solutions describe scenarios in which the cell that receives the RRC Connection Restore Request message contacts the last serving cell of the user equipment explained here. This is a viable option since the RRC connection re-establishment request message includes the temporary cell id of your last serving cell. This range of solutions is called, in 3GPP, “UE context recovery solutions”. Prior art solutions maintain the RRC connection since the RLF recovery procedure is successful within the time specified by the timer that regulates this procedure. However, prior art solutions imply that the outage time remains at a high level, since the cell the UE landed on during RLF recovery has to communicate with the last serving cell of the UE and retrieve its context . This user equipment context retrieval procedure involves communication via X2, which requires some time. For non-delay critical services, offshore structure could cause problems in Transmission Control Protocol (TCP) execution for delay critical services, and second input terminal downtime is perceived by user equipment and may be perceived as irritating by a user of the equipment. summary
An objective of the present embodiments is to improve the performance of a user equipment within a radio communication network.
According to one aspect of the present embodiments, the object is achieved by a method in a user equipment for handling a radio link failure in a radio communication network. User equipment is served in a first cell controlled by a base station and the base station being comprised of the radio communication network. User equipment detects a first indication of a failure of a radio link between user equipment and the base station. User equipment transmits a second radio link failure indication to the base station when the first indication of a failure is detected.
According to another aspect of the present embodiments, the objective is achieved by a user equipment to handle a radio link failure in a radio communication network. The base station is comprised of the radio communication network. User equipment comprises a detection circuit configured to detect a first indication of a failure of a radio link between user equipment and the base station. The user equipment further comprises a transmitter configured to transmit a second indication of a radio link failure to the base station when the first indication is detected.
According to another aspect of present embodiments, the object is achieved by a method in a radio base station to enable a user equipment to establish a connection in a radio communication network. User equipment is served in a first cell controlled by the base station. The base station is comprised of the radio communication network. The base station detects a radio link failure between user equipment and the base station by receiving a second indication from user equipment indicating that a radio link failure has been detected in user equipment. The base station detects the failure by further testing the radio link by transmitting a message to the user equipment and comparing whether a response is received from the user equipment within a second amount of time. If the second time value expires, the failure is detected. The base station further forwards a user equipment context from the user equipment to a circuitry controlling a second cell when the fault is detected. The user equipment context makes it possible for the circuitry controlling the second cell to serve the user equipment. In this way, the user equipment is enabled to establish the connection in the radio communication network.
According to another aspect of the present embodiments, the objective is achieved by a radio base station to enable a user equipment to establish a connection in a radio communication network. User equipment is served in a first cell controlled by the base station. The base station comprises a detection circuit configured to detect a failure of a radio link between user equipment indicating a detected radio link failure in user equipment. The detection circuit comprises a test circuit configured to test the radio link by transmitting a message to the user equipment and comparing whether a response is received from the user equipment within a second amount of time. If the second time value expires, the fault will be detected. The base station further comprises a forwarding circuit configured to forward a user equipment context from the user equipment to a circuitry controlling a second cell when the fault is detected. The user equipment context makes it possible for the circuitry controlling the second cell to serve the user equipment by enabling the user equipment to establish the connection in the radio communication network.
The present embodiments imply a faster RLF recovery by reducing interruption times to low values when the user equipment informs the radio base station of a possible radio link failure, i.e., the second indication of a failure. The base station can then forward the user equipment context to the circuitry controlling the second cell or cells. The user equipment context is thus present in the circuitry of the second cell in a set-up request from the user equipment, and the interruption time is reduced. as downtime is reduced, user equipment performance is improved. Brief description of drawings
Modes of realization will now be described in more detail in relation to the attached drawings, in which:
Figure 1 is a block block diagram illustrating a radio communication network, Figure 2 is a combined schematic flowchart and signaling scheme in a radio communication network, Figure 3 is a schematic overview of a process during the establishing a connection, Figure 4 is a schematic flowchart of embodiments disclosed herein, Figure 5 is a schematic flowchart of embodiments disclosed herein, Figure 6 is a schematic flowchart of a method in a radio communication network Figure 7 is a block block diagram illustrating a user equipment, Figure 8 is a block block diagram illustrating a base station, and Figure 9 is a schematic flowchart of a method at a base station. Detailed DescriptionFigure 1 is a block diagram illustrating a radio communication network as a Long Term Evolution (LTE) system, LTE-Advanced, 3rd Generation Partnership Project (3GPP) Wideband Code Division Multiple Access (WCDMA) System, Global System for Mobile communications/Enhanced Data rate for GSM Evolution (GSM/EDGE), Worldwide Interoperability for Microwave Access (WiMax), or Ultra Mobile Broadband (UMB), just to name a few.
A user equipment 10 is comprised in the radio communication network. The user equipment 10 is served in a first cell 14 controlled by a first radio base station 12. The user equipment 10 moves towards a second cell 16 controlled by a second radio base station 13. The radio base stations 12, 13 provide radio coverage within a geographic area forming the respective cell 14, 16. The first user equipment 10 in the first cell 14 is in communication with the first radio base station 12 in an uplink transmission (UL) when data is transmitted to the first base station 12 in a downlink (DL) transmission when data is sent to the first user equipment 10 by the first base station 12.
User equipment 10 can, for example, be represented by a wireless communication terminal, a mobile cell phone, a Personal Digital Assistant (PDA), an old user equipment, a wireless platform, a laptop, a computer or any type of digital device capable of wireless communication with radio base stations 12, 13.
The respective base station 12, 13 may also be referred to, for example, as NodeB (node B), an evolved node B (eNB, eNODE B), a base station transceiver, Access Point Base Station, base station rotator , or any other network unit capable of communicating with a user equipment 10 within cells 14, 16 served by the respective base station 12, 13, depending, for example, on the radio access technology and terminology used.
As mentioned above, the user equipment 10 moves to the second cell 16 and it may happen that a radio link failure (RLF) occurs during a transfer of the user equipment 10 from the first cell 14 to the second cell 16. radio link can also occur when entering a radio coverage hole or similar situations in which user equipment 10 loses a connection to the network.
According to the present embodiments, the first base station 12 detects whether a radio link failure has occurred. This is detected by receiving an indication, also referred to herein as a second indication, from the user equipment 10. When the first base station 12 detects that a radio link failure has occurred, the first base station 12 forwards an equipment context from user equipment 10 to a circuitry in the second base station 13. The circuitry controls the second cell 16. The circuitry may comprise hardware and/or software within the base station 13 configured to provide radio coverage on the second cell 16. It should be noted that the first base station 12 may serve the second cell 16 and comprise the circuitry that controls the second cell 16.
User equipment context may comprise user subscription information such as established radio bearer, Quality of Service (QoS) and transport parameters, security context, transfer restriction and/or similar user equipment data. In addition, the user equipment context enables the circuitry controlling the second cell 16 to serve the user equipment 10. Thus, by routing the user equipment context to the circuitry controlling the second cell 16, the user equipment context will already be present in the circuitry when user equipment 10 tries to c to the second cell 16.
Thus, the first base station 12 detects the RLF in user equipment 10 by receiving a second indication from user equipment 10 that user equipment 10 will most likely declare an RLF. Such second indication may, for example, one or more Random Access Channel (RACH) attempts after the user equipment 10 has detected RLF or an appropriately defined specific indicator value (CQI). The RACH attempt can use existing preambles, or new preambles defined for this purpose. A preamble is a string of bits used to identify a transmission. In order to provide this second indication, the user equipment 10 can monitor each radio link, called a restorer, connected to the first radio base station 12.
Thereby, by detecting RLF, the first base station 12 forwards the user equipment context, for example, to N neighboring cells. In case the first base station 12 has received a measurement report by the user equipment 10 for which the RLF has been detected, the first base station 12 can forward this user equipment context to a target cell, for example the second cell 16 indicated by measurement report but N-1 cells. Otherwise, these neighboring cells may be cells indicated by measurements of previous mobilities to/from the first cell 14, or cells having signaled another high cell interference from the first base station 12; that is, the cells to which the user equipment context is forwarded need not be all neighboring cells.
The present embodiments describe a combination of using tools in the user equipment 10 in order to track RLF in such a way that the complexity of the user equipment 10 does not increase considerably. The RLF is detected by the second indication of the user equipment 10 and thus the user equipment helps the first base station 12 to detect the RLF efficiently. The second indication is transmitted by the user equipment 10 only when one or more criteria of the radio link is satisfied, that is, it detects a first indication of a possible RLF, such first indication may be signal quality indicating that the radio link has been deteriorated, traffic activity may be below the expected value, and/or out of sync indication, also referred to as a third indication, has been received.
When the user equipment context is forwarded and thus already made available in the second cell 16 to which the user equipment 10 transmits an RRC connection re-establishment request message, the total time duration of the recovery procedure is significantly reduced.
Figure 2 is a combined flowchart and signaling scheme in a radio communication network. The flow chart and signaling scheme enables the user equipment 10 to establish or re-establish a connection in the radio communication network after a radio link failure in an efficient and fast manner. The user equipment 10 is served in the first cell 14, which is controlled by the first base station 12. The base station 12 comprises the radio communication network. User equipment 10 is connected over a radio link or link to the first base station 12, as indicated by the arrow denoted communication.
Step 200. User equipment 10 determines that a possible radio link radio link failure has occurred by detecting the first indication of a radio link failure between user equipment 10 and base station 12. For example, user equipment 10 can monitor channel quality and traffic activity to determine whether a radio link failure has possibly occurred. User equipment 10 may alternatively or additionally determine whether a possible radio link failure has occurred when user equipment 10 receives a significant out-of-sync indication in a DL synchronization procedure of the first base station 12. Significantly out of synchronization means that a time difference from the perfect time synchronization instant is higher than a maximum time deviation that is observed within the cell.
Step 201. The user equipment 10 then transmits the second indication or notification of a radio link failure to the first base station 12. In this way, the user equipment 10 transmits the second indication to the last serving base station.
Step 202. The first base station 12 then detects that a radio link failure has occurred by receiving the second indication of a radio link failure from the user equipment 10 and radio link monitoring. That is, base station 12 may, in some embodiments, query user equipment 10 after receiving the second indication to test whether a radio link failure has actually occurred.
Step 203. The first radio base station 12 then forwards a user equipment context from the user equipment 10 to at least one cell, e.g., the cell with the strongest reported signal. Thus, the user equipment context is present in at least one cell when the user equipment 10 tries to establish a connection to a circuitry controlling the at least one cell.
An additional scenario is when the user equipment 10 retrieves in a given cell, for example, the second cell 16, after RLF, receives its user equipment context in the second cell 16, but then the user equipment 10 returns to its previous serving cell, eg first cell 14, the one before RLF detection. The user equipment 10 may also, while returning to its previous cell, the first cell 14, detect another RLF. This may be the case where a first RLF is detected when user equipment 10 is about to ping-pong, a second RLF then being detected when user equipment 10 is trying to return to first cell 14 in a effort to correct your previous decision. A ping-pong transfer means that the transfer between cells 14, 16 is repeated back and forth.
In this case, the user equipment 10 ends up in the first cell 14, in which the user equipment is no longer available, when the user equipment context has been routed to the circuitry controlling or serving the second cell 16. Consequently, the first base station 12 needs to search the user equipment context again. Or, even worse, the user equipment 10 detects an RLF when transmitting a transfer confirmation message for a new service level. In this case, the user equipment context is not available in the second cell 16, where the user equipment 10 detects the RLF, when the second base station 13 has not extracted the user equipment context yet. In the event that user equipment 10 tries to recover from the RLF in another third cell or in the first cell 14, those radio base stations controlling the cells cannot extract the user equipment context, since the last serving cell, the second cell 16, is not in possession of the user equipment context. These cases can mainly occur when user equipment 10 declares RLF during a ping-pong HO and refer to an unsuccessful ping-pong Ho execution. In order to combat these cases and the case where ping-pong HO is triggered and executed successfully, the following is provided.
Step 204. In some embodiments, in which the user equipment context is routed to the circuitry controlling the second cell, the target cell, or to circuits controlling N neighboring cells, during successful HO execution or during routing of User equipment context when detecting RLF in the first base station 12 According to the present embodiments, the user equipment context of this user equipment 10 may be stored in the parent base station 12 for a certain period of time, referred to. here as third time heat T3, which is set by a Timer 3 storage timer.
If it is estimated that this storage of user equipment context in the first base station 12 could lead to unnecessary loading of the first base station 12, then the first base station 12 can store this user equipment context only when aggressive HO triggers are used. The reason is that the suggested method is intended to provide a solution for the case where ping-pong HOs do occur and those that typically do when aggressive HO shots are used. Aggressive transfer triggers are defined as triggers with relatively short time thresholds to be used during transfers.
Thus, user equipment context storage can only occur when conditions (EQ1) and (EQ3) are satisfied, which are typically indications of aggressive triggers HO:HO_hysteresis < Threshold_1 (EQ1) Time to trigger < Threshold_2 (EQ2 ) Where
HO_hysteresis defines the number of attempts back and forth to perform a transfer between cells, eTime to trigger defines length of time period to trigger a transfer.
Threshold_ can be adjusted so that the user equipment context is only stored when HO hysteresis is not large enough to protect against ping-pong transfers. Typical values for Threshold_1 are 3-4dBs. Threshold_2 can be adjusted so that the user context is only stored when the trigger time is not long enough to ensure that no ping-pong transfer occurs. Typical values of Threshold_2 are 640-1280ms.
Step 205. In order to be able to make use of user equipment context at a later stage, the previous serving base station, for example the first base station 12, may have to request security information such as encrypted passwords used in the second cell 16 to which the user equipment 10 is now connected. Therefore, the first base station 12 can request this security information from cells controlling circuits to which the user equipment context is forwarded, and to which cells the first base station 12 can detect that the user equipment 10 is connected. In the illustrated example, the first base station 12 requests the encrypted passwords from the second base station 12 controlling the second cell 16.
Step 206. The second base station 12 then transmits the encrypted passwords to the first base station 12 so that the first base station 12 can use the user equipment context.
Step 207. User equipment 10 and second base station 13 can establish a connection using the user equipment context.
Figure 3 is a block diagram illustrating an embodiment of a process during a radio link failure in a radio communication network. A radio link failure occurs in different processes such as before, during or after a transfer between different cells, a coverage hole occurrence in the radio communication network, or i. A coverage hole is an area within the radio coverage of the radio communication network in which the signal level is below a design threshold. Cover hole is typically caused by physical obstructions such as buildings, trees, hills, tunnels, and indoor parking garages.
RLFO step. User equipment 10 detects the first indication that a radio link failure between user equipment 10 and the first base station 12 has occurred.
In some embodiments, user equipment 10 tracks channel quality of the radio link. When the channel quality is below a threshold, the user equipment 10 can initiate a monitoring of a traffic activity over the radio link. From traffic activity, user equipment 10 can determine that the first indication that a radio link failure may have possibly occurred has been detected. When this is determined, the user equipment 10 can transmit a Channel Quality Indicator (CQI) with a specific value. The specific value can be 0 or ‘-1’ and the first base station 12 can then know that a possible radio link failure has occurred by reading the specific value of the received CQI. The first radio base station 12 may have previously stored the specific value or the specific value may be pre-configured in the first radio base station 12.
In some embodiments, user equipment 10 may alternatively or additionally determine that user equipment 10 is not synchronized with the radio communication network, indicating a radio link failure. For example, user equipment 10 may receive several consecutive out-of-sync indications and not receive an indication of being in-sync during a pre-set time interval. An indication of out of sync may occur when the radio link quality, when the Signal/Noise Interference Ratio (SINR) or similar, falls below a low threshold value for sync and an indication of being in sync may occur when the radio link quality is above a high threshold value for synchronization. The low threshold value can be lower than or equal to the high threshold value.
In some embodiments, the user equipment 10 can detect an out-of-sync indication via a downlink control channel (PDCCH) from the first radio base station 12, similarly to the out-of-sync indications explained above. User equipment 10 may have stored some timing information and then user equipment 10 may attempt a random access procedure over a Random Access Channel (RACH) as indicated by the arrow RLFO’. In this way, the first radio base station 12 can be informed that the random access request is coming from user equipment that is “on the verge of dying” or becoming disconnected. That is, the first radio base station 12 can detect that a radio link failure has likely occurred while receiving the random access request, which is likely to be severely unsynchronized to a radio network clock. Here, it severely means that the random access request is out of sync with a time difference greater than a time advance value that the first cell 14 supports. In these embodiments, the first radio base station 12 may query user equipment 10 about becoming disconnected by transmitting an uplink schedule acceptance to these user equipments. In case the uplink transmission is received at the first radio base station 12, the first radio base station 12 already here forwards the user equipment context to one or more neighboring cell circuits or control cells, for example, the second cell 16.
Step RLF1. In some embodiments, the user equipment 10, after detecting the first indication of a radio link failure, synchronizes with the radio communication network, which synchronization requires a time to perform the process. A sync time interval T10 required to sync to the system is defined as a time between steps RLF1-RLF0.
RLF2 step. User equipment 10 can select a better cell in terms of signal strength measurement such as Reference Signal Received Power (RSRP) or Reference Signal Received Quality (RSRQ). This can be performed by measuring over a reference signal and identifying the best cell in terms of RSRP or RSRQ, respectively. A second required time interval T11 is defined as a selection time indicating the time between steps RFF2 to RLF1.
RLF3 step. The user equipment can then initiate a random access procedure for the best selected cell at time RLF3 after listening to a Physical Broadcast Channel (P-BCH) and a System Information Broadcast (SIB) channel of the best selected cell . A third time interval T12 required in order to hear P-BCH and SIBs is defined as the time between RLF3-RLF2 steps.
RLF4 step. The random access procedure is completed and successful at time RLF4. A fourth time interval T13 required to complete the random access procedure is defined as random access time indicating time between steps RLF4-RLF3.
RLF5 step. User equipment 10 may transmit a Radio Resource Control Connection Re-establishment (RRC) message at time RLF5. A fifth time T14 required is defined as the time required to transmit the RCC connection request message, that is, the time between steps RLF5-RLF4.
RLF6 step. User equipment 10 may then receive a RCC Connection Re-establishment Completed at time RLF6 response. A sixth time interval T15 is required between steps RLF6-RLF5.
According to these embodiments, the sixth time interval T15 is minimized by introducing a radio link failure detection mechanism in the user equipment 10 as described above in combination with a forwarding mechanism in the first radio base station. 12. In this way, the first radio base station 12 detects the radio link failure when the second indication from the user equipment 10 is received and from the user equipment radio link test 10. After the radio link failure is detected, the first radio base station 12 forwards the user equipment context to one or more circuits controlling one or more cells. The presence of the user equipment context in the circuitry controlling the second cell 16 reduces the time between the time the user equipment 10 transmits the RCC Connection Reset Request message and the time the user equipment 10 receives the response over the network, in the form of a Completed RCC Connection Restoration. This sixth time interval T15 depends on whether user equipment context is available in the cell in which user equipment 10 is landed after RLF. This delay ranges from tens of milliseconds to over 200 milliseconds currently, thus accounting for 1050% of the global RLF retrieval duration; By forwarding the user equipment context, the user equipment context becomes available in the first or second cell 14, 16 in which the user equipment 10 tries to recover from the RLF and the time interruption is minimized.
Figure 4 shows embodiments of a method enabling the user equipment 10 to establish a connection in the radio communication network. Steps 400-405 are performed on user equipment 10 and steps 410-414 are performed on base station 12.
Step 400. In some of the present embodiments, the user equipment 10 can track a channel quality of the radio link held with the first base station 12 within the first cell 14. In this regard, the user equipment 10 can track measurements such as DL Channel Quality Indicator (CQI) reports, or various Hybrid Automatic Request (HARQ) Non-acknowledgements (NACKs) sent to user equipment 10. In this way, user equipment 10 can track the quality of channel of the radio link between user equipment 10 and the first radio base station 12.
Step 401. User equipment 10 can then determine if the radio link is deteriorating, indicating a possible radio link failure event. For example, in the above-mentioned performance measure indicates a deterioration of the radio link with the first radio base station 12, for example, in the case of one or both: avg_DL_SINR<Threshold_3, and (EQ3)#consecutive_HARQ_NACKs> Threshold_4 (EQ4) are detected for the radio link to the first radio base station 12, then the user equipment 10 can start monitoring the traffic activity, see step 402. avg_DL_SINR sets an average of the Signal/Noise plus Interference (SINR) ratio ) in the DL, and #consecutivos_HARQ_NACKs defines the number of consecutive HARQ NACKs received. Threshold_3 and Threshold_4 can be pre-set, dynamically adjusted or continuously updated.
This implies that some average of N CQI values, where N defines the number, can be made in user equipment 10. Since this measurement may also reflect the dynamic behavior of the radio link, the reasonable approach is that N is not a big number.
In this way, the user equipment 10 can determine if the channel quality exceeds one or more upper threshold values and/or is below one or more lower threshold values. If the radio link is not determined to be deteriorated, the process can return to step 400.
In some embodiments, user equipment 10 detects that user equipment 10 is very close to detecting the first indication of an RLF, user equipment 10 can then instantly indicate the probability of RLF to the first radio base station 12 by transmitting a specific CQI as shown by the dashed arrow for step 405.
Step 402. The user equipment 10 can monitor traffic activity over the radio link between the user equipment 10 and the base station 12 when the tracked channel quality exceeds the upper threshold value and/or is below the lower value of threshold. For example, when at least one of the equations (EQ3) and (EQ4) or a combination of them has been satisfied, the user equipment 10 can start monitoring the traffic activity for the radio link to the first radio base station 12 For example, user equipment 10 tracks an interarrival time, tinter, of scheduling requests sent and DL or UL scheduling responses received on user equipment 10. An average interarrival time of scheduling requests or responses. schedule, avg_tinter, may be an appropriate indication of traffic activity for user equipment 10.
Activity tracking at a physical layer can only be performed when there is also increased protocol layer activity, for both Downlink and Uplink traffic. The physical layer comprises the basic hardware transmission technologies of a network. User equipment 10 can track of higher layer protocol activity. This can be accomplished by observing data buffers in user equipment 10 in a layer of Medium Access Control (MAC), Radio Link Control (RLC), Packet Data Convergence Protocol (PDCR) and Control Protocol of Transmission (TCP). Data buffers storing transmitter information are used to indicate Uplink activity and buffers storing receiver information indicate Downlink activity.
Step 403. For user equipment 10 monitoring traffic activity, upon receiving a schedule acceptance, UL or DL, and/or when transmitting a schedule request, user equipment 10 may start a first timer, denoted as Timer_1. A first time threshold T1 of the first timer can be equal to the average interarrival time between schedule requests or acceptances plus one additional offset, denoted as offset_1: Stopwatch_1 = avg_tinter + offset_1 (EQ5)
The offset value_1 can be set to a value such that the timer_1 has a first time threshold T1 equivalent to a value of a timer detecting RLF in user equipment 10 specified in the TS 36.331 standard document, for example, timer T310. The first time threshold T1 can be updated as needed.
In some embodiments, timer_1 is only activated when user equipment 10 comprises a buffer that is not empty and only when higher layers, for example, Packet Data Convergence Protocol (PDCP) and Transmission Control Protocol (TCP), Hypertext Transfer Protocol (HTTP), indicate that there is traffic activity as mentioned above.
Step 404. User equipment 10 can determine if the first time threshold T1 has expired. If the first time threshold T1 of timer_1 has not expired, the radio link is considered to be working and the process can return to step 402. IF the first time threshold T1 is exceeded, the radio link is indicated as failing .
Step 405. Upon expiration of timer _1, user equipment 10 can transmit a CQI value to the first serving base station 12, which value is a specific value indicating that user equipment 10 is tending to RLF.
The steps below, 410-414, are performed at the first base station 12, as indicated by the dashed line.
Step 410. By receiving the CQI with the specific value indicating RLF, the first radio base station 12 can transmit an UL schedule acceptance message to user equipment 10, requesting to receive, for example, a report on the buffer size of the user equipment.
Step 411. The first radio base station 12 may then start, upon transmitting the UL schedule acceptance, a second timer, denoted timer_2, which has a second time value T2, which can be pre-set or adjusted to measured statistics.
Step 412. The first radio base station 12 can then determine whether the second timer 2 expires before receiving a UL transmission from the user equipment 10. If the second time value T2 has not expired when receiving the UL transmission, the radio link is considered to be working and the process may terminate.
Step 413. In the event that the first radio base station 12 does not receive the UL transmission from the user equipment 10 before T2 expires, then the user equipment context of this user equipment 10 can be forwarded to the circuit or circuits controlling an N number from neighboring cells, where N can be 1 or greater.
If the user equipment 10 has reported measurements made on reference signals, then, most likely in these measurements, the best cell in terms of RSRP, or a so-called target cell, would have been indicated, such as the second cell 16. The first station Radio base 12 may then forward the user equipment context to a set of circuits controlling this second cell 16 and perhaps to other circuits controlling N-1 other cells. These other cells can be cells indicated by a previous mobility history in the first cell 14. For example, in LTE Release 8, the first radio base station 12 can track cells in which user equipment, such as user equipment 10, are transferred. In this way, information about the most likely target cells is available.
Another type of information that can be used to define the cells to which the user equipment context should be forwarded is that of X2 messages about Overload (OI) indications received by neighboring cells. X2 is a communication interface between radio base stations. This information is a good indication of some user equipment in the first cell 14 being close to other neighboring cells and creating interference for those neighboring cells.
For example, in a Manhattan scenario, user equipment 10 almost always ends up in the target cell and the same applies approximately 80% of the time in a high-speed train scenario. Thus, in some embodiments, routing to circuits controlling the target cell and one or more cells may be sufficient. It can happen that all cells to which the user equipment context is forwarded are controlled by the same base station. In this case, a signaling message via X2 is sufficient.
Step 414. As mentioned above, the first base station 12 can store the user equipment context for the third time value T3 seconds defined by the storage timer, Timer_3, and request the circuit or circuits controlling one or more cells for which the user equipment context was forwarded to send their encrypted passwords.
It should be noted that user equipment 10 may transmit the second indication to the first radio base station 12 after determining that the channel quality is below a pre-set threshold, as indicated by the dashed arrow. In this way, the first radio base station 12 can monitor the traffic activity of the user equipment 10 before testing the radio link.
Figure 5 shows embodiments of a method of enabling the user equipment 10 to establish a connection in the radio communication network. Steps 500-504 are performed on user equipment 10 and steps 510-514 are performed on base station 12.
Step 500. User equipment 10 receives DL PDCCH, Primary Sync Signal (PSS), Secondary Sync Signal (SSS) and/or other system sync information in DL, for example, by Broadcast Control Channel (BCCH ) from the first radio base station 12.
Step 501. User equipment 10 can store cell synchronization radio communication network information such as clock speed or the like.
Step 502. User equipment 10 verifies that it is in sync at each transmission time interval (TTI). For example, user equipment 10 receives several consecutive out-of-sync indications or third indications and does not receive a out-of-sync indication during a time interval. An indication of out-of-sync may be when the radio link quality, such as Signal/Noise-to-Noise Ratio (SINR) or similar, falls below a low sync threshold value which may be lower than the value of high synchronization threshold.
In some embodiments, the user equipment 10 can detect an out-of-sync indication over a physical downlink control channel (PDCCH) of the first radio base station 12, similarly to the out-of-sync indications explained above.
If user equipment 10 determines that it is in sync, the process can return to step 500.
Step 503. When user equipment 10 is out of sync, it can transmit a random access request by RCH. Random access can be transmitted, for example, at a time evaluated on the basis of stored radio communication network or cell synchronization information. In this way, the user equipment can instantly attempt a random access to the first radio base station 12 using the stored clock.
Steps 510-514 below are performed on the first radio base station 12, as indicated by the dashed line.
Step 510. The first radio base station 12 receives the random access request which may be out of clock synchronization at the radio base station 12.
Step 511. When receiving a random access request with a large time difference from the exact synchronization instant, that is, a time difference greater than a time advance value that the first cell 14 supports, the The first radio base station 12 then can transmit an UL schedule acceptance to user equipment 10 which is likely to detect an RLF soon. The first radio base station 12 is advised of the identity of user equipment 10 and others in the first cell 14, since the first radio base station 12 monitors active radio links in the first cell 14. The UL Schedule Acceptance Message to the user equipment 10 can request, for example, a report on a buffer size of the user equipment 10. Before consulting the user equipment 10, the base station 12 can monitor the channel quality and/or traffic activity from the radio link.
Step 512. The first radio base station 12 can then start a second timer, timer_2, which has a second time value T2.
Step 513. The first radio base station 12 can then determine whether the second timer, timer_2, expires before receiving the UL transmission from the user equipment 10.
If T2 has not expired when receiving the UL transmission, the radio link is considered functional and the process ends.
Step 514. In case the first radio base station 12 does not obtain the UL transmission from the user equipment 10, then the user equipment context of this user equipment 10 is forwarded to a circuit or circuits controlling N neighboring cells, where N can be 1 or greater.
If user equipment 10 has reported measurements made on reference signals, then most likely in these measurements the best cell in terms of RSRP, or a so-called target cell may have been indicated, such as the second cell 16. The first base station radio 12 may then forward the user equipment context to a circuitry controlling this second cell 16 and perhaps N-1 circuitry of other cells. These other cells can be those indicated by a previous mobility history in the first cell 14. For example, in LTE Release 8, the first radio base station 12 can track the cells in which user equipment , such as user equipment 10 , are transferred. In this way, information about the most likely target cell will be available.
Another type of information that can be used to define the cells to which the user equipment context should be forwarded are X2 messages about Overload Indication (OI) received by neighboring cells. X2 is a communication interface between radio base stations. This information is a good indication of some user equipment in the first cell 14 next to another neighboring cell and creating interference for those neighboring cells.
For example, in a Manhattan scenario, user equipment 10 almost always ends up in the target cell and the same applies approximately 80% of the time in a high-speed train scenario. Thus, in some embodiments, routing to the circuitry controlling the target cell and 1 or more circuitry controlling another cell is sufficient. It can happen that all cells to which the user equipment context is forwarded are controlled by the same base station. In this case, a signaling message via X2 is sufficient.
Step 515. As mentioned above, the first radio base station 12 can store the user equipment context for the third time value T3 seconds, defined by the Stopwatch_3 storage timer and request one or more cells, i.e. controlling circuits to one or more cells, to which the user equipment context has been forwarded, send their encrypted passwords.
Method steps in user equipment 10 for handling radio link failure in the radio communication network according to some general embodiments will now be described with reference to a flowchart illustrated in Figure 6. The steps do not have to be considered. in the order mentioned below, but they can be considered in any suitable order. The user equipment 10 is served in a first cell 14 controlled by a base station 12 and the base station 12 is comprised in the radio communication network.
Step 601. User equipment 10 detects a first indication of a radio link failure between user equipment 10 and base station 12.
Step 602. User equipment 10 may, in some embodiments, as indicated by the dashed line, track a channel quality of the radio link. For example, user equipment 10 can track radio link performance measurements.
Step 603. User equipment 10 may, in some embodiments, as indicated by the dashed line, determine whether the lime quality exceeds an upper threshold value and/or is below a lower threshold value.
In some embodiments, user equipment 10 tracks the channel quality of the radio link and determines whether the first indication of a failure is detected when the channel quality exceeds an upper threshold value and/or falls below a value. lower threshold.
Step 604. User equipment 10 may, in some embodiments, as indicated by the dashed line, monitor traffic activity over the radio link when the quality of the tracked channel exceeds the upper threshold value and/or is below the lower threshold value.
Step 605. User equipment 10 can, in some embodiments. As indicated by the dashed line, plot a time between receiving or transmitting a first scheduling message and receiving or transmitting a second scheduling message. For example, user equipment 10 may plot the time between transmitting a schedule request and receiving a schedule acceptance, UL or DL.
Step 606. User equipment 10 can, in some embodiments as indicated by the dashed line, determine whether the first indication of a radio link failure is detected when traffic activity falls below an activity threshold, and if there is buffered data or protocol activity in user equipment 10 to base station 12.
Step 607. User equipment 10 may, in some embodiments, as indicated by the dashed line, compare the plotted time with a first time threshold (T1) to determine if the first indication of a radio link failure has been detected . Thereby, the user equipment 10 transmits, see step 610, the second indication to the base station 12 when the plotted time exceeds the first time threshold (T1).
The first time threshold (T1) may comprise an average time between previous consecutive received scheduling messages or previous transmitted consecutive scheduling messages, and a time offset. For example, an average inter-arrival time of schedule requests or acceptances, avg_tinter, may be an appropriate indication of traffic activity for user equipment 10. The time offset can be adjusted to a value so that the first time threshold T1 is equivalent to the value of timer T310 in TS 36.331.
Step 608. In some embodiments as indicated by dashed line, user equipment 10 may store a radio communication network time clock. For example, the user equipment 10 can store the clock transmitted by the base station 12.
Step 609. In some embodiments as indicated by dashed line, user equipment 10 may receive a third indication that user equipment 10 is out of synchronization with the radio communication network. Then, the second radio link failure indication in step 610 below may comprise a random access channel request. The random access channel request can be transmitted when the user equipment 10 detects the third indication that the user equipment 10 is out of sync. The second indication can be transmitted by using the stored clock time.
Step 610. User equipment 10 transmits the second radio link failure indication to radio base station 12 when the first indication of a failure is detected, which second indication can be used as a trigger to forward a user equipment context to a circuitry 131 controlling a second cell 16. The circuitry 131 may comprise hardware and/or software within a base station configured to provide radio coverage over the second cell 16. It should be noted that the base station 12 may serve the first cell 14 as well as the second cell 16 and comprise the circuitry that controls the second cell 16.
The user equipment context enables the circuitry 131 controlling the second cell 16 to serve the user equipment 10, where the user equipment context is used when the connection in the radio communication network is established.
In order to carry out the method for handling radio link failure in the radio communication network, a user equipment is provided. Figure 7 is a block diagram illustrating user equipment 10. User equipment 10 is served in a first cell 14 controlled by base station 12.
User equipment 10 comprises a detection circuit 701 configured to detect a first indication of a radio link failure between user equipment 10 and base station 12.
Detection circuit 701 may further be configured to track a channel quality of the radio link and determine whether the channel quality exceeds an upper threshold value and/or is below a lower threshold value. The detection circuit 701 can then monitor a traffic activity over the radio link when the tracked channel quality exceeds the upper threshold value and/or is below a lower threshold value. Detection circuit 701 can then, when traffic activity falls below an activity threshold and there is buffered data or protocol activity in user equipment 10 to base station 12, determine whether a first indication of a failure of radio link is detected.
Sensing circuit 701 may be further configured to plot a time between receiving or transmitting a first scheduling message, and receiving or transmitting a second scheduling message. For example, a time between receiving a DL schedule acceptance and transmitting an acknowledgment of the received schedule acceptance.
In some embodiments, detection circuit 701 may be further configured to track a channel quality of the radio link and determine, based merely on channel quality, whether the first indication of a fault is detected when the channel quality tracked exceeds an upper threshold value and/or is below a lower threshold value.
The user equipment further comprises a transmitter 702 configured to transmit a second indication of a radio link failure when the first indication of a speech is detected. The second indication can be used as a trigger to forward a user equipment context from the user equipment 10 to a circuitry 131 controlling a second cell 16. The circuitry 131 may comprise hardware and/or software within a station radio base configured to provide radio coverage over second cell 16. It should be noted that radio base station 12 may serve first cell 14 as well as second cell 16 and comprise circuitry 131 that controls second cell 16 .
The user equipment context enables the circuitry 131 controlling the second cell 16 to serve the user equipment 10 in which the user equipment context is used when establishing the connection in the radio communication network.
In some embodiments, detection circuit 701 may be further configured to compare the tracked time against a first time threshold T1. Transmitter 702 can then be configured to transmit the second indication when the tracked time exceeds the first time threshold T1. The first time threshold T1 may comprise an average time between previously received consecutive scheduling messages or previously transmitted consecutive scheduling messages, and a time offset.
Alternatively or additionally, the detection circuit 701 may, in some embodiments, be configured to store a clock time of the radio communication network in a memory 703 of the user equipment 10. The detection circuit 701 may then be configured to detect a third synchronization indication that the user equipment 10 is out of synchronization with the radio communication network. The second radio link failure indication to be transmitted to the radio base station 12 may then comprise a random access channel request transmitted when the user equipment 10 detects the third synchronization indication that the user equipment 10 is out of sync. The second indication can then be transmitted by using stored clock time.
Memory 703 may comprise one or more memory units, and may be used to store, for example, data such as threshold values, quality values, timers, application to perform the present methods being performed on the user equipment 10 or similar.
The present embodiments for handling radio link failure in a radio communication network can be implemented through one or more processors, such as a processing circuit 704 in the user equipment 10 illustrated in Figure 7, along with program code to perform the functions and/or method steps of the present embodiments. The program code mentioned above can also be provided as a computer program product, for example, in the form of a data carrier carrying computer program code to execute the present solution when loaded into the user equipment 10. Such a carrier it can be in the form of a CD ROM disk. However it is visible with other data carriers such as memory stick. The computer program code can furthermore be provided optical path pure program code on a server and downloaded to the user equipment 10.
Figure 8 is a block diagram of the base station 12 receiving the second indication from the user equipment 10. The user equipment 10 is served in the first cell 14 controlled by the base station 12.
The base station 12 comprises a detection circuit 801 configured to receive the second indication from the user equipment 10. The detection circuit 801 is configured to detect a radio link failure between the user equipment 10 and the base station 12, by receiving the second indication from the user equipment indicating a radio link failure detected in the user equipment 10.
Sensing circuit 801 comprises a test circuit 802 configured to test the radio link by transmitting a message to user equipment 10 and comparing whether a response is received from user equipment 10 within a second time value T2 of a second timer 803 comprising the second time value T2.
The radio base station 12 comprises a forwarding circuit 804 and if the second time value T2 expires, the failure is detected, the forwarding circuit 802 being configured to forward a user equipment context of the user equipment 10 to a circuitry 131 controlling a second cell 16, for example, to forward user equipment context to circuits controlling N neighboring cells.
The base station 12 may further comprise a storage timer 805, during which means 805 the base station 12 may store the user equipment context in a memory 807 for T3 seconds. The base station 12 can also request the encrypted passwords from N neighboring cells. Memory 807 can comprise one or more memory units and can be used to store, for example, data such as threshold values, quality values, user equipment context, timers, encrypted passwords, application to perform the present methods on being run on and base station 12 or similar.
The present embodiments, which enable the user equipment 10 to establish a connection in a radio communication network, can be implemented through one or more processors, as a processing circuit 806 in the base station 12 shown in Figure 8, together with computer program code to perform the functions and/or method steps of the present embodiments. The above-mentioned program code may also be provided as a computer program product, e.g. in the form of a data carrier carrying computer program code to execute the present solution upon loading into the radio base station 12. Such a carrier may be in the form of a CD ROM disk. However, it is feasible with other data carriers such as memory stick. The computer program code can be further provided as pure program code on a server and downloaded to the base station 12.
Method steps at base station 12 for enabling user equipment 10 to establish a connection in the radio communication network in accordance with some general embodiments will now be described with reference to a flowchart illustrated in Figure 9. The steps have no which may be considered in the order below, and may be considered in any suitable order. The user equipment 10 is served in the first cell 14 controlled by the base station 12 and the base station 12 is comprised in the radio communication network.
Step 901. Base station 12 detects a radio link failure between user equipment 10 and base station 12 by receiving the second indication from user equipment 10. The second indication indicates a radio link failure detected in user equipment. user 10. Base station 12 detects the failure of testing the radio link by transmitting a message to the user equipment. The base station 12 then compares whether a response is received from the user equipment 10 within a second time value T2, and if the second time value T2 expires, the fault will be detected.
Step 902. The base station 12 forwards a user equipment context from the user equipment 10 to a circuitry controlling a second cell 16 when the fault is detected. The user equipment context enables user equipment 10 to establish the connection in the radio communication network. The circuitry may comprise hardware and/or software within a radio base station 12 or other radio base station configured to provide radio coverage over the second cell 16.
In the drawings and report, exemplary embodiments have been explained. However, many variations and modifications can be made to these embodiments without departing substantially from the principles of the embodiments.
Consequently, although specific terms are used, they are used in a generic and descriptive sense only and not for the purpose of limitation, the scope of the invention being defined by the following claims.

权利要求:
Claims (14)
[0001]
1. Method in a user equipment (10) for handling radio link failure in a radio communication network, which user equipment (210) is served in a first cell (14) controlled by a radio base station ( 12), radio base station (12) which is comprised in the radio communication network, the method characterized in that it comprises:- detecting (200, 601) a first indication of a radio link failure between the user equipment (10) and the base station (12); by - tracking (400, 602) a channel quality of the radio link; - determining (401, 603) at least one of whether the channel quality exceeds an upper threshold value and/or if the channel quality is below a lower threshold value; - monitor (402, 604) a traffic activity over the radio link when at least one of the tracked channel quality exceeds the upper threshold value and/or the tracked channel quality falls below the value lower threshold; and - determine (404, 606) whether the first indication of a failure is detected when the traffic activity tracked falls below an activity threshold, and there is buffered data or protocol activity in the user equipment (10) for the station base radio (12); and - transmitting (201, 405, 503, 610) a second radio link failure indication to the base station (12) when the first indication of a failure is detected.
[0002]
2. Method according to claim 1, characterized in that said monitoring (604) comprises tracking (605) a time between reception or transmission of a first scheduling message and reception or transmission of a second scheduling message.
[0003]
3. Method according to claim 2, characterized in that determining (606) whether the first indication of a failure was detected comprises comparing (607) the tracked time with a first time threshold (T1), and in which to transmit ( 610) said second indication comprises transmitting the second indication when the tracked time exceeds the first time threshold (T1).
[0004]
4. Method according to claim 3, characterized in that the first time threshold (T1) comprises an average time between previously received consecutive scheduling messages or previously transmitted consecutive scheduling messages, and a time offset.
[0005]
5. Method according to any one of claims 1 to 4, characterized in that the detection (601) of the first indication comprises: - storing (601, 608) a clock time of the radio communication network; - detecting (502 , 609) the first indication in response to receiving a third indication that the user equipment (10) is out of synchronization with the radio communication network; wherein transmitting the second indication comprises transmitting the second indication upon detecting the third indication and using the stored clock time as a request on the random access channel.
[0006]
6. User equipment (10) for handling a radio link failure in a radio communication network, characterized in that it is served in a first cell (14) controlled by a radio base station (12) and radio base station (12) this being comprised in the radio communication network, the user equipment (10) comprising: a detection circuit (701) configured to detect a first indication of a radio link failure between the user equipment (10 ) and the base station (12); by tracking a channel quality of the radio link; determining whether at least one of the channel quality exceeds an upper threshold value and/or whether the channel quality is below a lower threshold value; radio link when at least one of the tracked channel quality exceeds the upper threshold value and/or the tracked channel quality is below the lower threshold value; and determining whether the first indication of a failure is detected when traffic activity falls below an activity threshold, and whether there is buffered data or protocol activity in the user equipment (10) for the radio base station (12); and a transmitter (702) configured to transmit a second indication of a radio link failure to base station (12) when the first indication is detected.
[0007]
7. User equipment (10) according to claim 6, characterized in that the detection circuit (701) is further configured to track a time between the reception or transmission of a first scheduling message and the reception or transmission of a second scheduling message.
[0008]
8. User equipment (10) according to claim 7, characterized in that the detection circuit (701) is further configured to compare the tracked time with a first time threshold (T1), and in which the transmitter ( 702) is configured to transmit the second indication when the tracked time exceeds the first time threshold (T1).
[0009]
9. User equipment (120) according to claim 8, characterized in that the first time threshold (T1) comprises an average time between previously received consecutive scheduling messages or previously transmitted consecutive scheduling messages, and a deviation of time.
[0010]
User equipment (10) according to any one of claims 6 to 9, characterized in that the detection circuit (701) is further configured to store a radio communication network clock time in a memory (703 ) of the user equipment (10), and detecting the first indication in response to receiving a third indication that the user equipment (10) is out of synchronization with the radio communication network, and that the transmitter is configured to transmitting the second indication upon detecting the third indication and using the stored clock time as a random access channel request.
[0011]
11. Radio base station (12) to enable a user equipment (10) to establish a connection in a radio communications network, the user equipment (10) being served in a first cell (14) controlled by the radio base station (12), the base station characterized in that it comprises: a detection circuit (801) comprising a test circuit configured to detect a failure of a radio link between the user equipment (10) and the base radio station ( 12) on: receipt of an indication from user equipment indicating a radio link failure detected in user equipment (10), in response to receipt of said indication, test the radio link on the test circuit (802) configured to test the radio link by transmitting a message to the user equipment (10) and determine whether a response is received from the user equipment (10) within a second time value (T2) and if the second time value ( T2) expires, to fal ha is detected; and a forwarding circuit (804) configured to forward a user equipment context of the user equipment (10) to a circuitry controlling a second cell (16) when the fault is detected, which user equipment context enables the circuitry controlling the second cell (16) serves the user equipment (10) and thus enabling the user equipment (10) to establish the connection in the radio communication network.
[0012]
12. Radio base station according to claim 11, characterized in that the detection circuit is configured to transmit an out-of-sync indication to the user equipment (10) that the user equipment (10 ) is out of synchronization with the radio communication network, and receiving an indication from the user equipment (10) indicating that the user equipment (10) has detected a radio link failure by receiving a request on an access channel random that is out of sync from a clock on the base station (12).
[0013]
13. Method at a radio base station (12) to enable a user equipment (10) to establish a connection in a radio communication network, the user equipment (10) being served in a first cell (14) controlled by the base radio station (12), and the base radio station (12) being comprised in the radio communication network, the method characterized in that it comprises:- detecting (510, 901) a radio link failure between the user equipment (10) and the radio base station (12) by: receiving an indication from the user equipment indicating a detected radio link failure in response to receiving said indication, testing (410, 511) the radio link by transmitting a message to the user equipment (10), and determining whether a response is received from the user equipment (10) within a second time value (T2) and, if the second time value (T2) expires, the fault is detected; and forwarding (413, 514, 902) a user equipment context of the user equipment (10) to a circuitry controlling a second cell (16) when the fault is detected, said user equipment context enables the set. of circuits controlling the second cell (16) serve the user equipment (10), and thus enable the user equipment (10) to establish the connection in the radio communication network.
[0014]
14. Method according to claim 13, characterized in that the method further comprises transmitting an indication of lack of synchronization to the user equipment (10) indicating that the user equipment (10) is out of synchronization with the network. radio communication, and in which receiving indication from the user equipment (10) indicating that the user equipment has detected (10) a failure in the radio link comprises receiving a request over a random access channel that is out of sync from of a clock on the base station (12).

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同族专利:

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公开号 | 公开日

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CA2790535A1|2011-08-25|

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US8515415B2|2013-08-20|

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RU2012140486A|2014-03-27|

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BR112012020879A2|2016-05-03|

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SG183125A1|2012-09-27|

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法律状态:
2019-01-08| B06F| Objections, documents and/or translations needed after an examination request according [chapter 6.6 patent gazette]|

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2020-01-28| B06U| Preliminary requirement: requests with searches performed by other patent offices: procedure suspended [chapter 6.21 patent gazette]|

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2020-03-10| B25A| Requested transfer of rights approved|Owner name: GUANGDONG OPPO MOBILE TELECOMMUNICATIONS CORP., LTD. (CN) |

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2021-04-06| B09A| Decision: intention to grant [chapter 9.1 patent gazette]|

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2021-06-15| B16A| Patent or certificate of addition of invention granted|Free format text: PRAZO DE VALIDADE: 20 (VINTE) ANOS CONTADOS A PARTIR DE 23/12/2010, OBSERVADAS AS CONDICOES LEGAIS. PATENTE CONCEDIDA CONFORME ADI 5.529/DF |

优先权:

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申请号 | 申请日 | 专利标题

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US30675710P| true| 2010-02-22|2010-02-22|

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US61/306,757|2010-02-22|

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PCT/SE2010/051481|WO2011102774A1|2010-02-22|2010-12-23|Detection of radio link failurefor recovery|

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