• 专利附录
  • 专利说明
  • 权利要求
  • 类似技术
  • 同族专利
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    • 专利摘要:
    The present invention relates to a method (50) for transmitting broadcast signals by a group of base stations (31) to terminals (20) of a wireless communication system (10), each base station comprising a coverage area, the coverage areas of said group base stations being geographically distributed so as to serve a geographical area. According to the invention, the broadcast signals being of limited duration and transmitted in a frequency band used by all the base stations of the group, the base stations (31) of the group are synchronized temporally with each other and the broadcasting signals of said stations. base (31) of the group are time multiplexed. The invention also relates to a method (60) adapted to receive the broadcast signals.
    公开号:FR3034945A1
    申请号:FR1553125
    申请日:2015-04-10
    公开日:2016-10-14
    发明作者:Benoit Ponsard；Raoul Mallart；Lionel Zirphile
    申请人:Sigfox SA；
    IPC主号:
    专利说明:

    [0001] TECHNICAL FIELD The present invention belongs to the field of wireless communication systems, and more particularly relates to a method for transmitting broadcast signals by a group of base stations of an access network intended for terminals, as well as a method of receiving said broadcast signals. STATE OF THE ART The present invention finds a particularly advantageous, though in no way limiting, application in ultra-narrowband wireless communication systems. "Ultra-narrow band" ("Ultra Narrow Band" or UNB in the English literature) means that the instantaneous frequency spectrum of the radio signals emitted by the terminals, to the access network, is of lower frequency width to one kilohertz.
    [0002] Such UNB wireless communication systems are particularly suitable for applications of the type M2M (acronym for machine-to-machine) or the Internet of Things ("Internet of Things" or loT in the literature Anglo-Saxon). In such a UNB wireless communication system, the data exchanges are essentially monodirectional, in this case on a rising link between terminals and an access network of said system. The terminals transmit uplink messages that are collected by base stations of the access network, without having to first associate with one or more base stations of the access network. In other words, the upstream messages sent by a terminal are not intended for a specific base station of the access network, and the terminal transmits its upstream messages assuming that they can be received by at least one forwarding station. based. Such provisions are advantageous in that the terminal does not need to make regular measurements, particularly greedy in terms of power consumption, to determine the most appropriate base station to receive its upstream messages. The complexity lies in the access network, which must be able to receive uplink messages that can be transmitted at arbitrary times and on arbitrary central frequencies.
    [0003] 3034945 2 Each base station of the access network receives upstream messages from the different terminals that are within its reach. Such a mode of operation, in which the data exchanges are essentially monodirectional, is quite satisfactory for many applications, such as, for example, remote reading of gas meters, water meters, electricity meters, telemonitoring of buildings or houses, etc. In some applications, however, it may be advantageous to also be able to perform data exchanges in the other direction, namely on a downlink from the access network to the terminals.
    [0004] In particular, it may be advantageous to transmit broadcast signals, global or group (respectively "broadcast" or "multicast" in the Anglo-Saxon literature), to the terminals. In particular, several frequency bands may be possible for the transmission of the upstream messages, for example respectively associated with different geographical regions which may be subject to different regulatory constraints. The emission of broadcast signals could then enable the terminals to identify the frequency band of the uplink link in the geographic region in which they are located, and before sending up messages in a frequency band not provided for this purpose. For example, it would be possible to transmit the broadcast signals in the frequency band of the uplink or in a frequency band having a predefined frequency deviation from the frequency band of the uplink. Such broadcast signals could also be implemented to transmit any type of information that may be useful for all terminals, or for a large number of them. However, to limit the manufacturing cost of the terminals, the detection of the broadcast signals must be able to be carried out in a simple and economical way from an electrical consumption point of view. In addition, the broadcast signals must be transmitted by limiting the impact on the collection of the upstream messages. In particular, to reduce the cost of deploying the access network, it can be envisaged to use half-duplex base stations, that is to say base stations that can receive messages and send up signals broadcast, but not 3034945 3 simultaneously. In such a case, a base station that transmits a broadcast signal is no longer available to receive upstream messages sent by the terminals, so that upstream messages may be missed. DISCLOSURE OF THE INVENTION The object of the present invention is to remedy all or part of the limitations of the solutions of the prior art, in particular those described above. For this purpose, and according to a first aspect, the invention relates to a method of transmitting broadcast signals by a group of base stations to terminals of a wireless communication system, each base station having a coverage area, the coverage areas of said group base stations being geographically distributed so as to serve a geographical area. Furthermore, since the broadcast signals are of limited duration and transmitted in the same frequency band used by all the base stations of the group, the base stations of the group are synchronized temporally with each other and the broadcasting signals of different base stations. of the group are temporally multiplexed. Thus, a group of base stations serving a geographical area uses the same frequency band to transmit the broadcast signals. Therefore, once the known frequency band of a terminal, it is enough for him to always listen to the same frequency band as long as he is in the same geographical area, so that listening to the downlink, which does not require not to listen successively several different frequency bands, is particularly simple and economical from an electrical consumption point of view.
    [0005] In addition, the base stations of the group are synchronized temporally, and the broadcast signals they transmit are time multiplexed, i.e. said broadcast signals of the base stations of the group are transmitted in intervals. respective separate time. Therefore, a terminal does not have to handle the simultaneous arrival of several broadcast signals, which facilitates the processing necessary to detect and decode each broadcast signal. In addition, at each moment there is at most one base station of the group that transmits a broadcast signal. Therefore, if the group has 3034945 4 NG base stations, and these are also half-duplex, then there is always at least (NG - 1) base stations that may be available for receiving messages. amounts. The impact on the collection of the uplink messages is therefore limited if the base stations are half-duplex, and may be further reduced if the coverage areas of the adjacent base stations of the group have a geographic overlap. In particular modes of implementation, the transmission method may further comprise one or more of the following characteristics, taken separately or in any technically possible combination.
    [0006] In particular embodiments, the base stations of the group belong to respective different sets, each set comprising a plurality of base stations belonging to respective different groups serving different respective geographic areas, and the base stations. of the same set simultaneously transmit the broadcast signals. In particular modes of implementation, the base stations are geographically distributed so that adjacent base stations of different groups belong to different sets. In particular modes of implementation, the sending times of the broadcast signals are predefined instants in Coordinated Universal Time Scale UTC. In particular modes of implementation, the broadcast signals emitted by the group of base stations have a frequency overlap.
    [0007] In particular modes of implementation, the coverage areas of adjacent base stations in the group are geographically overlapping. In particular modes of implementation, the wireless communication system comprising several geographical regions 30 each comprising several groups of base stations, the broadcast signals of different geographical regions are time multiplexed. In particular embodiments, the broadcast signals of different geographical regions are grouped temporally. In particular embodiments, the broadcast signals of the base stations of the group are transmitted according to a predefined time multiplexing pattern repeated according to a predefined repetition pattern, and the base station broadcast signals comprise identifiers allowing to distinguish said broadcast signals within the temporal multiplex pattern. Such arrangements are advantageous in that each terminal, when it has detected a broadcast signal, can then estimate a theoretical start time of a subsequent time division multiplex pattern. For example, if a terminal moves in the geographical area, it can determine from what moment it must listen to the downlink to be able to receive the first broadcast signal of the time-division multiplex pattern, issued by one of the base stations of the group. This is also valid if the terminal 15 passes from one geographical area to another, when the base stations are organized in sets and the base stations of the same set simultaneously transmit their broadcast signals. In particular embodiments, the broadcast signals further include information to distinguish time division multiplex patterns within the repetition pattern. In particular modes of implementation, the duration of the time division multiplexing pattern is at least ten times smaller than the minimum duration between two repetitions of the temporal multiplexing pattern. According to a second aspect, the present invention relates to an access network of a wireless communication system, comprising base stations comprising means configured to transmit broadcast signals, to terminals, according to a method of transmission according to any one of the embodiments of the invention. In preferred embodiments, all or some of the base stations of the access network are of the semidoplex type. According to a third aspect, the present invention relates to a method of reception, by a terminal, of broadcast signals transmitted according to a transmission method according to any one of the embodiments of the invention.
    [0008] More particularly, said reception method comprises the initial time synchronization of the terminal with an access network of the wireless communication system, the estimation of a theoretical start time of a subsequent temporal multiplexing pattern and the search. broadcast signals according to said theoretical start time. When a broadcast signal is detected, said reception method comprises: measuring a reception instant of said detected broadcast signal; extracting the identifier of said detected broadcast signal; terminal with the access network according to the extracted identifier, the time-division multiplexing pattern, the measured reception time and the theoretical start time of the detected time-division multiplexing pattern. According to a fourth aspect, the present invention relates to a terminal 15 comprising means configured to implement a method of receiving broadcast signals according to any of the embodiments of the invention. PRESENTATION OF THE FIGURES The invention will be better understood on reading the following description given by way of non-limiting example and with reference to the figures which represent: FIG. 1: a schematic representation of a communication system Figure 2: An example of a geographical distribution of base stations in a geographical area; Figure 3: a diagram illustrating the main steps of a method of broadcasting broadcast signals by a group of base stations. 4: time diagrams illustrating a preferred mode of implementation, in which the broadcast signals of the base stations of a group are transmitted according to a predefined temporal multiplexing pattern, FIG. geographical distribution of groups of 3034945 7 base stations in a geographical area, Figure 6: a diagram illustrating the main steps of a method of receiving signals from dif merger by a terminal. In these figures, identical references from one figure to another 5 designate identical or similar elements. For the sake of clarity, the elements shown are not to scale unless otherwise stated. DETAILED DESCRIPTION OF EMBODIMENTS FIG. 1 schematically represents a wireless communication system 10, for example of the UNB type, comprising several terminals 20 and an access network 30 comprising several base stations 31. The terminals 20 and the stations base 31 of the access network 30 exchange data in the form of radio signals. By "radio signal" is meant an electromagnetic wave propagating via non-wired means, whose frequencies are within the traditional spectrum of radio waves (a few hertz to several hundred gigahertz). The terminals 20 are adapted to transmit uplink messages on a uplink link to the access network 30.
    [0009] Each base station 31 is adapted to receive the upstream messages from the terminals 20 which are within range. Each incoming message thus received is for example transmitted to a server 32 of the access network 30, possibly accompanied by other information such as an identifier of the base station 31 which received it, the measured power of said received message amount, the received date and / or the measured center frequency of said received amount message, etc. The server 32 processes, for example, all the received messages received from the different base stations 31. In addition, the access network 30 is also adapted to transmit, via the base stations 31, broadcast signals on the network. a downlink to the terminals 20, which are adapted to receive them. The broadcast signals may be broadcast signals in the English literature and / or group broadcast signals ("multicast" in the Anglo-Saxon literature).
    [0010] Conventionally, a base station 31 has a coverage area such that, for terminals 20 in said coverage area, the uplink messages transmitted by these terminals 20 are likely to be detected by said base station. 31, and the broadcast signals transmitted by said base station 31 are likely to be received by these terminals. It should be noted that the coverage area of a base station 31 is not necessarily the same for the up link and for the downlink. In the remainder of the description, one places oneself in a nonlimiting manner in the case where the coverage area on the up link and the coverage area on the downlink are identical. Conventionally, the base stations 31 of the access network 30 are distributed geographically so as to be able to serve a large number of terminals 20. FIG. 2 schematically represents a group of NG base stations 31 located in geographical locations. different, whose coverage areas together serve a geographical area ZG1. In the nonlimiting example illustrated in FIG. 2, the number NG of base stations 31 of the group is equal to 7, and the said NG base stations 31 of the group are designated respectively by 31-1 to 31-7 when they are to be distinguished, and their coverage areas are designated ZC1 through ZC7, respectively. In the example illustrated in FIG. 2, the coverage areas ZC1 to ZC7 are schematically represented as having no geographical overlap with each other. Preferably, however, the coverage areas of adjacent base stations in the group will overlap geographically. Thus, a terminal 20 is capable, in the areas of geographical overlap, of receiving broadcast signals transmitted by different base stations 31, which in principle makes it possible to reduce the listening time required to detect at least one signal of diffusion. In addition, uplink messages sent by a terminal 20 are likely to be received by several base stations 31, which is advantageous especially in the case of half-duplex base stations, which are not available for reception when they emit a diffusion signal on the downlink, but also to improve the link budget by exploiting a greater spatial diversity. Preferably, the geographical overlap between coverage areas of adjacent base stations 31 is such that, in each position within the geographical area ZG1, an amount message sent by a terminal 20 is likely to be received by 5 least two base stations 31 and / or said terminal 20 is capable of receiving broadcast signals transmitted by at least two base stations 31. The present invention relates in particular to a method 50 for transmitting broadcast signals by a group of stations base 31, as shown in FIG. 2, as well as a method 60 for receiving these broadcast signals from the terminals 20, which are described in detail hereinafter. A) Broadcast signal transmission method The broadcast signal transmission method 50 is implemented by the access network 30 of the UNB wireless communication system 10. In the remainder of the description, reference is made to the case where said method 50 for transmitting broadcast signals is implemented mainly by the base stations 31 of said access network 30. The base stations 31 comprise by for this purpose, respective processing modules (not shown in the figures), each processing module comprising for example one or more processors and storage means (magnetic hard disk, electronic memory, optical disk, etc.). wherein a computer program product is stored in the form of a set of program code instructions to be executed to implement the different steps of the broadcast signal transmission method. In a variant, each processing module 25 comprises one or more programmable logic circuits, of the FPGA, PLD, etc. type, and / or specialized integrated circuits (ASIC) adapted to implement all or part of said process steps 50. transmission of broadcast signals. Each base station 31 further comprises wireless communication means, known to those skilled in the art, enabling said base station to receive upstream messages and to transmit broadcast signals in the form of radio signals. In other words, the base stations 31 of the access network 30 comprise respective means configured in software (product 3034945) and / or hardware (FPGA, PLD, ASIC, etc.) for implement the various steps of the method 50 for transmitting broadcast signals. The broadcast signals transmitted by the base stations 31 are of limited duration, for example between a few hundred milliseconds and a few seconds. In addition, according to the invention, the base stations 31 of the group transmit the broadcast signals in the same frequency band, which is therefore shared by said base stations of the group. In the remainder of the description, reference is made in a nonlimiting manner to the case of a frequency band of width 200 kilohertz. The frequency band in which the base stations 31 of the group transmit the broadcast signals may be identical to the frequency band of the uplink, in which the terminals 20 transmit the uplinks, or a frequency band having a predefined frequency deviation with respect to 15 said frequency band of the uplink, etc. It should be noted that, although the uplink messages transmitted by the terminals 20 are ultra-narrowband in a UNB wireless communication system, the broadcast signals themselves are not necessarily ultra-narrowband and may have a spectral width. instant greater than one kilohertz.
    [0011] In the remainder of the description, reference is made in a nonlimiting manner in the case where the diffusion signals are also ultra-narrowband, which corresponds to a preferred embodiment of the invention. FIG. 3 diagrammatically represents the main steps of a broadcast signal transmission method 50, which are: time synchronization of the base stations 31-1 to 31-7 of the group, transmission of the broadcast signals by the various base stations 31-1 to 31-7 of the group, the broadcast signals transmitted by different base stations being time multiplexed.
    [0012] Thus, and according to the invention, the broadcast signals of the various base stations 31-1 to 31-7 of the group, which are transmitted in the same frequency band, are furthermore multiplexed temporally. For this purpose, the base stations 31-1 to 31-7 of the group 3034945 11 are previously synchronized temporally, to ensure that said broadcast signals can be emitted successively without time overlap between them. Any method of time synchronization of the base stations 31-1 to 31-7 of the group between them can be implemented, and the choice of a particular method is only a variant of implementation of the invention. In addition, it should be noted that the accuracy of the time synchronization between the base stations 31 can be relatively low. For example, an accuracy of the order of one second is considered sufficient in the context of the invention, for example by providing guard intervals between the successive transmission signal transmissions, in order to prevent these signals from occurring. overlap in time. Since the broadcast signals are time-multiplexed, they are preferably transmitted close to one another in the frequency domain, in order to limit the width of the listening frequency band of each terminal 20, which may possibly be if necessary, be less than 200 kilohertz. For example, the broadcast signals transmitted by the base station group 31-1 to 31-7 may have frequency overlap. Frequency overlap may be only partial. However, the broadcast signals are preferably transmitted on the same center frequency, so that the frequency overlap is integral, i.e. they are substantially superimposed in the frequency domain. Thus, each terminal 20, if it knows the central frequency on which said broadcast signals are emitted, can then listen to the downlink with a reduced width listening frequency band, of the order of the instantaneous spectral width of the signals. broadcast signals. FIG. 4 diagrammatically represents time diagrams illustrating a nonlimiting example in which the broadcasting signals of the base stations 31-1 to 31-7 of the group are transmitted in a predefined temporal multiplexing pattern.
    [0013] By "predefined time division multiplex pattern" is meant that said broadcast signals of said base stations 31-1 to 31-7 of the group are transmitted in a predefined order and at respective transmission times having predefined time differences between them, to the accuracy of time synchronization close by. If we consider broadcast signals duration of the order of one second, then the time differences can be for example of the order of a few seconds to a few tens of seconds. For example, and as shown in FIG. 4, the base stations 31-1 to 31-7 successively transmit diffusion signals SD1 to 5D7 at respective transmission instants Ti to T7: T2 transmission has a time difference At1, greater than the duration of the broadcast signal SD1, with respect to Ti, - the transmission instant T3 has a time difference At2, greater than the duration of the diffusion signal 5D2, by relative to T2, the time of emission T4 has a time difference At3, greater than the duration of the diffusion signal 5D3, with respect to T3, the time of emission T5 has a time difference At4, greater than the duration of the diffusion signal 5D4, with respect to T4, the emission instant T6 has a time difference At5, greater than the duration of the diffusion signal 5D5, with respect to T5, the emission instant T7 has a time difference At6, greater than the duration of the diffusion signal 5D6, with respect to T6. The temporal multiplexing pattern is, for example, repeated recursively. It should be noted that the content of the broadcast signals SD1 to 5D7 may vary from one time division multiplex pattern to another, in contrast to the transmission order of the broadcast signals by the base stations 31-1 to 31. 7 and the time differences between the transmission instants of said broadcast signals is the same from one temporal multiplexing pattern to another.
    [0014] In preferred embodiments, the time division multiplex pattern, including the broadcast signals SD1 to 5D7, is repeated in a predefined repetition pattern. For example, the time division multiplex pattern may be periodically repeated with a predefined AT repeat period.
    [0015] In another example, the repetition pattern of the time division multiplex pattern may consist of repeating said time division multiplexing pattern at predefined instants, which can be indexed on the Coordinated Universal Time-Scale UTC. For example, the repetition pattern of the time division multiplexing pattern may consist of repeating said temporal multiplex pattern over a day at 04:00 UTC, 10:00 UTC, 16:00 UTC and 22:00. UTC. The repetition pattern can itself be repeated every day. Preferably, the duration of the time division multiplex pattern is at least ten times less than the minimum duration between two repetitions of said time multiplexing pattern, or even at least a hundred times smaller. Thus, the emissions of the broadcast signals SD1 to SD7 are grouped in time. Therefore, if a terminal 20 knows approximately when at least one broadcast signal is likely to be received, then said terminal 20 can easily, while listening to the downlink frequency band for a duration that can be quite short (from the order of the duration of a few broadcast signals), detect all the broadcast signals transmitted by base stations 31 in the coverage areas of which said terminal 20 is located. Between two temporal multiplexing patterns, that is to say say most of the time, the terminal 20 can then go into sleep mode on the downlink. In preferred embodiments, the broadcast signals SD1 to SD7 include identifiers for distinguishing base stations 31-1 to 31-7 from the group. Thus, a terminal 20 which detects a broadcast signal can determine, by means of the identifier and from the temporal multiplexing pattern, the rank of said detected broadcast signal in the temporal multiplexing pattern. The broadcast signals SD1 to SD7 may also include information to distinguish time division multiplex patterns within the repeating pattern, particularly when these are not repeated periodically. In the example illustrated in FIG. 3, the base stations 31-1 to 31-7 are distributed geographically so as to serve a geographical zone ZG1. In order to serve a large geographical area, it is possible to provide several groups of NG base stations 31, 30 of which serve different respective geographical areas which are distributed within the geographical region in question. Where appropriate, the base stations 31 of the different groups are, in preferred embodiments, organized into respective NG sets 3034945 14 different from base stations 31. Thus, the NG base stations 31 of each group belong to respective different sets, designated BS1 to BS7, considering NG equal to 7. Preferably, the base stations 31 of the same set are synchronized temporally with each other and simultaneously transmit their broadcast signals. Consequently, the base stations 31 of the set BS1 simultaneously transmit their broadcast signals, the base stations 31 of the set BS2 simultaneously transmit their broadcast signals, the base stations 31 of the set BS3 simultaneously transmit their broadcast signals, etc. If one considers a temporal multiplexing pattern of the broadcast signals, then said temporal multiplexing pattern is repeated simultaneously in all geographical areas. The benefits described above at the level of a geographical area are then extended to a plurality of geographical areas.
    [0016] Figure 5 schematically shows an example of geographical distribution of different groups of base stations 31 serving different geographic areas ZG1 to ZG4. In the example illustrated in FIG. 5, the geographical zones ZG1 to ZG4 are schematically represented as having no geographical overlap with each other. However, there is nothing to preclude having adjacent geographic areas that overlap geographically. In addition, in this example, the base stations 31 of different sets are organized, in each group, according to the same geographical distribution pattern, which makes it possible in particular to ensure that adjacent base stations 25 in the geographical region, but which belong to different groups, necessarily belong to different sets and therefore do not simultaneously emit their diffusion signals. Thus, in the same geographical region, the base stations 31 preferably emit all the broadcast signals in the same frequency band, and said broadcast signals are further multiplexed temporally within each geographical zone. Advantageously, the broadcast signals of the different groups of base stations 31 are transmitted in the same time interval. On the other hand, from one geographical region to another, it is possible to use a different frequency band for the broadcast signals, for example because the regulatory constraints are not the same. Where appropriate, the broadcast signals of different geographical regions are preferably time-multiplexed. In other words, the broadcast signals of each geographical region are transmitted in the same time interval, and different time intervals, without overlap between them, are used for the different geographical regions. In addition, the broadcast signal transmission time slots of the different geographical regions are preferably grouped temporally, in order to limit the duration of the downlink for a plurality of geographical regions by a terminal 20. B) Method for receiving broadcast signals FIG. 6 schematically illustrates the main steps of a method 60 of reception, by a terminal 20, of broadcast signals transmitted by the access network 30 in accordance with what has been described. above. For example, each terminal 20 comprises a processing module (not shown in the figures), comprising one or more processors and storage means (magnetic hard disk, electronic memory, optical disk, etc.) in which a program product is stored. 20 in the form of a set of program code instructions to be executed to implement the different steps of the broadcast signal receiving method 60. In a variant, the processing module comprises one or more programmable logic circuits, of the FPGA, PLD, etc. type, and / or specialized integrated circuits (ASIC) adapted to implement all or part of the said steps of the reception method 60. broadcast signals. Each terminal 20 furthermore comprises wireless communication means, considered as known to those skilled in the art, enabling said terminal to send up messages and to receive descendant messages in the form of radio signals.
    [0017] In other words, each terminal 20 comprises a set of means configured in software (specific computer program product) and / or hardware (FPGA, PLD, ASIC, etc.) to implement the various steps of the method 60 of receiving broadcast signals.
    [0018] As shown in FIG. 6, the method 60 for receiving broadcast signals by a terminal 20 firstly comprises a step 61 of initial synchronization of said terminal 20 with the access network 30. base stations 31, the accuracy of the time synchronization between the terminal 20 and the access network 30 may be relatively small. For example, a precision of the order of one second is considered sufficient in the context of the invention. The initial time synchronization of the terminal 20 with the access network 30 may implement any method known to those skilled in the art, and a particular method is only a variant of implementation of the invention. For example, the terminal 20 can synchronize initially by listening for a prolonged downlink, until the detection of at least one broadcast signal. If the broadcast signals are furthermore transmitted in a predefined temporal multiplexing pattern, then the terminal 20 can extract the identifier 15 from the detected broadcast signal and deduce from it the rank of said detected broadcast signal within said temporal multiplexing pattern. The terminal 20 can then estimate a theoretical start time of a subsequent time division multiplexing pattern, as a function, for example, of prior knowledge of the repetition pattern and, if appropriate, of the information extracted from the broadcast signal. 20 detected, making it possible to distinguish the temporal multiplexing patterns within said repetition pattern. In another example, the terminal 20 can synchronize initially by sending a request to the access network 30. The access network 30 then responds by sending a message down to said terminal 20, which includes information allowing the to synchronize temporally with the access network 30. For example, this synchronization information consists of the hour in UTC coordinated universal time scale (if the times of emission of broadcast signals are indexed on the scale coordinated universal time), or the waiting time until the beginning of the next temporal multiplex pattern, etc. The method 60 for receiving broadcast signals then comprises, when it is necessary to receive a broadcast signal, a step 62 for estimating a theoretical start time of a subsequent time division multiplexing pattern, and a step 63 of searching for broadcast signals as a function of said theoretical start time. Preferably, the terminal 20 is in standby mode on the downlink by default, and wakes up shortly before said theoretical start time of the time division multiplexing pattern, to listen to the downlink from said theoretical start time. When a broadcast signal is detected (reference 630 in FIG. 6), the reception method 60 comprises steps of: measuring the instant of reception of the detected broadcast signal, which corresponds, for example, to the time receiving said UTC coordinated universal time scale broadcast signal, - extracting the identifier of said detected broadcast signal, - time resetting the terminal 20 with the access network 30 as a function of the extracted identifier, the time division multiplexing pattern, the measured reception time and the theoretical start time of the detected time division multiplex pattern. For example, from the extracted identifier and the theoretical start time of the time division multiplex pattern, the terminal 20 can determine the theoretical reception time of the detected broadcast signal. The time difference between the measured reception instant and the theoretical reception instant of said detected signal enables the terminal 20 to reset its internal clock to that of the access network 30. When no broadcast signal is detected (reference 631 in FIG. 6), during the search step 63, after having listened to the downlink during the duration of a temporal multiplexing pattern, then the reception method 60 continues for example by resuming step 62 of estimating a theoretical start time of a subsequent time division multiplex pattern or resuming at step 61 initial time synchronization. More generally, it should be noted that the modes of implementation and embodiment considered above have been described by way of non-limiting examples, and that other variants are therefore possible. In particular, the invention has been described by considering a UNB wireless communication system. In other examples, nothing excludes the consideration of other types of wireless communication systems, including for which the instantaneous frequency spectrum of the radio signals emitted by the terminals is wider than one kilohertz.
    权利要求:
    Claims (4)
    [0001]
    CLAIMS1 - Method (50) for transmitting broadcast signals by a group of base stations (31) to terminals (20) of a wireless communication system (10), each base station (31) comprising a coverage area, the coverage areas of said base stations of the group being distributed geographically so as to serve a geographical area, characterized in that the broadcast signals being of limited duration and transmitted in the same frequency band used by all base stations of the group, the base stations (31) of the group are synchronized temporally with each other and the broadcasting signals of base stations (31) different from the group are time multiplexed. The method (50) of claim 1, wherein the base stations (31) of the group belong to respective different sets, each set comprising a plurality of base stations belonging to respective different groups serving different respective geographical areas, and wherein the base stations of the same set simultaneously transmit the broadcast signals. The method (50) of claim 2, wherein the base stations are geographically distributed so that adjacent base stations of different groups belong to different sets. Method (50) according to one of the preceding claims, in which the transmission times of the broadcast signals are predefined instants in Coordinated Universal Time Scale UTC. Method (50) according to one of the preceding claims, wherein the broadcast signals transmitted by the group of base stations have a frequency overlap. Method (50) according to one of the preceding claims, wherein the coverage areas of adjacent base stations of the group have a geographical overlap. Method (50) according to one of the preceding claims, wherein the wireless communication system (10) having a plurality of regions 10
    [0002]
    2 - 15
    [0003]
    3 - 20
    [0004]
    4 - 255 - 6 - 30 7 - 3034945 20 each having several groups of base stations (31), the broadcast signals of different geographical regions are time multiplexed. The method (50) of claim 7, wherein the broadcast signals of different geographical regions are time-grouped. 9 - Method (50) according to one of the preceding claims, wherein the broadcast signals of the base stations (31) of the group are transmitted in a predefined temporal multiplexing pattern repeated in a predefined repeating pattern, and in which the broadcast signals of the base stations (31) include identifiers for distinguishing said broadcast signals within the time division multiplex pattern. The method (50) of claim 9, wherein the broadcast signals further include information for distinguishing time division multiplex patterns within the repetition pattern. 11 - Method (50) according to one of claims 9 to 10, wherein the duration of the time multiplexing pattern is at least ten times less than the minimum duration between two repetitions of time division multiplex pattern. 12 - Access network (30) of a wireless communication system (10), characterized in that it comprises base stations (31) comprising means configured to transmit broadcast signals to terminals (20) according to a method (50) of emission according to one of the preceding claims. 13- access network (30) according to claim 12, wherein all or part of the base stations (31) are semi-duplex type. 14 - Method (60) of reception, by a terminal (20), of broadcast signals transmitted according to a transmission method (50) according to one of claims 9 to 11, characterized in that it comprises the synchronization ( 61) of the terminal (20) with an access network (30) of the wireless communication system (10), estimating (62) a theoretical start time of a subsequent time division multiplex pattern and the search (63) of broadcast signals as a function of said theoretical start time and, when a broadcast signal is detected: - the measurement (64) of a reception instant of said detected broadcast signal, - the extraction (65) of the identifier of said detected broadcast signal, - time registration (66) of the terminal (20) with the access network as a function of the extracted identifier, of the temporal multiplexing pattern, of the measured reception time and theoretical start time of the time-division multiplex pattern detected . 15- Terminal (20) characterized in that it comprises means configured to implement a method (60) for receiving broadcast signals according to claim 14.
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    同族专利:
    公开号 | 公开日
    CN107637149A|2018-01-26|
    US10492171B2|2019-11-26|
    MX2017012963A|2018-02-01|
    JP2018511269A|2018-04-19|
    EP3281472A1|2018-02-14|
    CN107637149B|2021-04-30|
    EP3281472B1|2020-02-19|
    US20180070333A1|2018-03-08|
    WO2016162649A1|2016-10-13|
    FR3034945B1|2018-04-20|
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    法律状态:
    2016-05-02| PLFP| Fee payment|Year of fee payment: 2 |
    2016-10-14| PLSC| Search report ready|Effective date: 20161014 |
    2017-05-02| PLFP| Fee payment|Year of fee payment: 3 |
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    2019-04-29| PLFP| Fee payment|Year of fee payment: 5 |
    2020-04-30| PLFP| Fee payment|Year of fee payment: 6 |
    2021-04-30| PLFP| Fee payment|Year of fee payment: 7 |
    优先权:
    申请号 | 申请日 | 专利标题
    FR1553125|2015-04-10|
    FR1553125A|FR3034945B1|2015-04-10|2015-04-10|METHODS FOR TRANSMITTING AND RECEIVING BROADCAST SIGNALS IN A WIRELESS COMMUNICATION SYSTEM|FR1553125A| FR3034945B1|2015-04-10|2015-04-10|METHODS FOR TRANSMITTING AND RECEIVING BROADCAST SIGNALS IN A WIRELESS COMMUNICATION SYSTEM|
    PCT/FR2016/050821| WO2016162649A1|2015-04-10|2016-04-08|Method for transmitting broadcast signals in a wireless communication system|
    CN201680027732.7A| CN107637149B|2015-04-10|2016-04-08|Method for transmitting broadcast signal in wireless communication system|
    EP16733126.3A| EP3281472B1|2015-04-10|2016-04-08|Method for transmitting broadcast signals in a wireless communication system|
    US15/565,304| US10492171B2|2015-04-10|2016-04-08|Method for transmitting broadcast signals in a wireless communication system|
    MX2017012963A| MX2017012963A|2015-04-10|2016-04-08|Method for transmitting broadcast signals in a wireless communication system.|
    JP2017552855A| JP7007192B2|2015-04-10|2016-04-08|Methods for transmitting broadcast signals in wireless communication systems|
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