JP2007053627A - Radio communication system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To effectively use frequency resources by synchronizing a master base station with each slave base station using a simple configuration and method, and preventing interference with adjacent slots and collisions of transmission data, in a time division multiplexing access. <P>SOLUTION: This system is a radio communication system, wherein the TDMA-system master radio base station and a plurality of slave base stations are connected to points/multipoints via wired transmission lines. The master radio base station transmits time division multiple packets, comprising synchronization information for performing slot synchronization of each slave radio base station, to the plurality of slave base stations. Each slave radio base station changes the slot timing of packets to be transmitted, on the basis of the synchronization information contained in received packets. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a wireless communication system having a plurality of TDMA wireless base stations, and more particularly, a master wireless base station and a plurality of slave wireless base stations that are point-to-multipoint connected via a wired transmission line such as an optical transmission line. Is related to slot synchronization.

  In a radio communication system having a plurality of radio base stations that perform TDMA radio communication, the timing of TDMA frames transmitted between radio base stations is synchronized in order to prevent transmission data collision and interference with adjacent slots due to frame timing shifts. Inter-base station synchronization is performed.

  In Patent Document 1, a slot timing difference between the head slot timing of data transmitted from a partner station and data transmitted by the local station is detected, and the transmission slot timing of the local station is adjusted according to the detected slot timing difference. Thus, a technique for synchronizing base stations without transmitting / receiving a synchronization signal between base stations is disclosed.

Japanese Patent Laid-Open No. 11-154939

  However, in the above prior art, in order to synchronize the base stations, it is necessary to provide a delay difference detector for detecting the difference between the slot timing of the head of the data transmitted from the partner station and the slot timing of the data transmitted by the own station. There is a problem that the device configuration becomes complicated.

  The present invention has been made in view of the above, and synchronizes the master base station and each slave base station with a simple configuration and technique, and prevents transmission data collisions and interference with adjacent slots in time division multiple access. An object of the present invention is to obtain a wireless communication system that can prevent and effectively use frequency resources.

  In order to solve the above-described problems and achieve the object, the present invention is a wireless communication system in which a TDMA-type master wireless base station and a plurality of slave base stations are connected to a point multipoint via a wired transmission path. The master radio base station transmits a time division multiplex packet including synchronization information for slot synchronizing each slave radio base station to a plurality of slave base stations, and each slave radio base station The slot timing of a packet to be transmitted is changed based on the included synchronization information.

  According to the present invention, each slave radio base station synchronizes the master base station and each slave base station by changing the slot timing of the packet to be transmitted based on the synchronization information included in the packet received from the master radio base station. Therefore, it is possible to synchronize the master base station and each slave base station with a simple configuration and method, thereby preventing collision of transmission data and interference with adjacent slots in time division multiple access. It is possible to provide a wireless communication system that can effectively use the.

  Embodiments of a wireless communication system according to the present invention will be described below in detail with reference to the drawings. Note that the present invention is not limited to the embodiments.

Embodiment 1 FIG.
FIG. 1 is a diagram showing a configuration example of a wireless communication system according to the present invention. The first wireless communication system having the first cell 1020A as a communication zone includes a master base station (BSm) 1000A, a plurality of slave base stations (BSr) 1011A, 1012A, 1013A subordinate to the master base station 1000A, and these An optical network (NW) 1030A as a wired transmission path that connects the master base station 1000A and a plurality of slave base stations 1011A, 1012A, and 1013A in a point-to-multipoint connection is configured. The first cell 1020A is covered by a master base station 1000A and a plurality of slave base stations 1011A, 1012A, 1013A.

  The second wireless communication system using the second cell 1020B as a communication zone includes a master base station (BSm) 1000B, a plurality of slave base stations (BSr) 1011B, 1012B, 1013B subordinate to the master base station 1000B, and these masters. An optical network (NW) 1030B as a wired transmission path that connects the base station 1000B and a plurality of slave base stations 1011B, 1012B, and 1013B in a point-multipoint connection is configured. The second cell 1020B is covered by a master base station 1000B and a plurality of slave base stations 1011B, 1012B, 1013B.

  Each base station of the first and second wireless communication systems transmits and receives a TDMA frame with a terminal (UE) 1040 using a time division multiplexing (TDMA) system. In this case, one terminal is used for convenience. At 1040, a plurality of terminals are represented. The master base station 1000A and the master base station 1000B are connected by an IP network 1050.

  FIG. 2 shows a configuration example of the optical network 1030A (1030B). In this case, EPON (Ethernet (registered trademark) Passive Optical Network) is adopted. In FIG. 2, an optical network 1030A includes an accommodation device (OLT) 2000, a plurality of termination devices 2021 to 2023, an optical transmission line 2011 that connects between the accommodation device 2000 and the plurality of termination devices 2021 to 2023, and a signal It comprises a coupler 2010 as an optical branching unit that performs distribution and coupling. The accommodation device 2000 is connected to the master base station 1000A and performs data and clock transmission / reception processing with the master base station 1000A.

  The first termination device 2021 is connected to the first slave base station 1011A, and performs data and clock transmission / reception processing with the first slave base station 1011A. The second terminal device 2022 is connected to the second slave base station 1012A and performs data and clock transmission / reception processing with the second slave base station 1012A. The third terminal device 2023 is connected to the third slave base station 1013A, and performs data and clock transmission / reception processing with the third slave base station 1013A.

  Here, in the optical network 1030A (1030B), the clock synchronization between the accommodation device 2000 and the first to third termination devices 2021 to 2023 is achieved by using a well-known clock synchronization method in EPON. That is, the first to third end devices 2021 to 2023 are operated in synchronization with the operation clock of the accommodation device 2000. Similarly, the slot timings of the terminal devices 2021 to 2023 are also synchronized, but the slot numbers assigned to the terminal devices 2021 to 2023 are not uniform or regular, and the terminal devices 2021 to 2021 are included in the accommodation device 2000. The slot number 2023 is managed.

[Downlink operation]
First, with reference to FIG. 3, the downlink operation for transmitting a signal from master base station 1000A to terminal 1040 will be described in the case of first cell 1020A.

  The accommodating device 2000 manages the slot timing difference information of the first terminating device 2021, the second terminating device 2022, and the third terminating device 2023 with respect to the accommodating device 2000, to the first master base station 1000A. Notification is made in advance. In the case of FIG. 3, the multiplexing number is N (N is a natural number), and the slot timing is N repetitions. In this case, the first termination device 2021 is delayed by 3 slots relative to the accommodation device 2000, the second termination device 2022 is delayed by 1 slot relative to the accommodation device 2000, and the termination device 2023 is (N− 2) The slot delay is set, and the receiving apparatus 2000 sets the third slot delay as the slot timing difference information for the first terminal apparatus 2021, the one slot delay as the slot timing difference information for the second terminal apparatus 2022, and the third (N−2) slot delay is notified to the first master base station 1000A as slot timing difference information for the terminal device 2023. Also, the first slave base station transmission slot is transmitted at the slot timing “0” of the accommodating device 2000, the second slave base station transmission slot is transmitted at the slot timing “1” of the accommodating device 2000, and the accommodating device It is assumed that a transmission slot for the third slave base station is transmitted at a slot timing “2” of 2000, and these slot timings are also notified from the accommodating apparatus 2000 to the first master base station 1000A in advance.

(Processing in master base station 1000A)
The first master base station 1000A synchronizes the first slave base station 1011A, the second slave base station 1012A, and the third slave base station 1013A based on the timing difference information notified from the accommodating device 2000. The first slave base station synchronization information, the second slave base station synchronization information, and the third slave base station synchronization information are generated. That is, in this case, the timing difference information notified from the accommodating device 2000 is used as it is, and the first slave base station synchronization information of “+3” indicating that the delay is 3 slots and the delay of 1 slot. "+1" indicating the second slave base station synchronization information, and "+ (N-2)" indicating the third slave base station synchronization information indicating that there is a delay.

  The first master base station 1000A supplies a clock to the accommodating device 2000 in the optical network 1030A and transmits the first slave base station transmission packet including the first slave base station synchronization information described above, The second slave base station transmission packet including the slave base station synchronization information and the third slave base station transmission packet including the third slave base station synchronization information are time-division multiplexed and serially transmitted. . In this case, the transmission packet for the first slave base station is assigned to the slot with the slot number “0”, the transmission packet for the second slave base station is assigned to the slot with the slot number “1”, and the third slave base station The transmission packet for the station is assigned to the slot with the slot number “2”.

(Processing in the optical network)
The accommodating device 2000 transmits the time-division multiplexed data transmitted from the first master base station 1000A to the coupler 2010 based on the clock supplied from the first master base station 1000A. That is, the accommodating apparatus 2000 sends a transmission packet for the first slave base station at the timing of the slot number “0”, sends a transmission packet for the second slave base station at the timing of the slot number “1”, 3 is transmitted at the timing of the slot number “2”. Note that the accommodation device 2000 and the first to third termination devices 2021 to 2022 achieve clock synchronization by using a well-known clock synchronization method in EPON based on the clock supplied from the master base station 1000A. The coupler 2010 distributes the time division multiplexed data received from the first master base station 1000A to the first termination device 2021, the second termination device 2022, and the third termination device 2023. The coupler 2010 simply outputs the received time division multiplexed data as it is in parallel from the three output ports.

  The first terminal device 2021 transmits to the first slave base station including the synchronization information for the first slave base station, which is data of the slot number “0” assigned to itself among the received time division multiplexed data. The packet is selected, and the selected transmission packet for the first slave base station is transmitted to the first slave base station 1011A. Also, the first termination device 2021 supplies its own operation clock to the first slave base station 1011A. In the example shown in FIG. 3, the transmission slot timing of the first termination device 2021 is delayed by 3 slots with respect to the accommodation device 2000.

  Similarly, the second terminal device 2022 receives the second slave base station including the second slave base station synchronization information that is the data of the slot number “1” assigned to itself among the received time division multiplexed data. The transmission packet for the station is selected, and the selected transmission packet for the second slave base station is transmitted to the second slave base station 1012A. Also, the second terminal device 2022 supplies its operation clock to the second slave base station 1012A. In the example shown in FIG. 3, the transmission slot timing of the second terminal device 2022 is delayed by one slot with respect to the accommodating device 2000.

  Similarly, the third terminal device 2023 receives the third slave base station including the third slave base station synchronization information which is the data of the slot number “2” assigned to itself among the received time division multiplexed data. The transmission packet for the station is selected, and the selected transmission packet for the third slave base station is transmitted to the third slave base station 1013A. The third terminal device 2023 supplies its own operation clock to the third slave base station 1013A. In the example shown in FIG. 3, the transmission slot timing of the third termination device 2023 is delayed by (N−2) slots with respect to the accommodation device 2000.

(Processing of each slave base station)
When the first slave base station 1011A receives the first slave base station transmission packet including the first slave base station synchronization information from the first terminal device 2021, the first slave base station transmission packet The first slave base station synchronization information is extracted from the first slave base station synchronization information and the first slave base station transmission information after the first slave base station synchronization information is extracted is transmitted as a transmission packet to the required terminal 1040. However, at this time, the first slave base station 1011A has a slot obtained by subtracting the slave base station synchronization information (in this case, “+3”) from the multiplex number N based on the clock signal supplied from the first terminal device 2021. After delaying the first slave base station transmission packet by several minutes, the first slave base station transmission packet is transmitted to the required terminal 1040 as a transmission packet. That is, in this case, the first slave base station 1011A transmits the packet received from the first terminal device 2021 to the required terminal 1040 after delaying (N-3) slots.

  As a result, the first slave base station 1011A can transmit the transmission slot to the terminal 1040 at the same slot timing “0” as the accommodating apparatus 2000, that is, at the same slot timing “0” as the first master base station 1000A. The transmission slots of the first master base station 1000A and the first slave base station 1011A can be synchronized.

  Similarly, when the second slave base station 1012A receives the second slave base station transmission packet including the second slave base station synchronization information from the second terminal device 2022, the second slave base station 1012A receives the second slave base station transmission packet. The second slave base station synchronization information is extracted from the transmission packet for transmission, and the second slave base station transmission packet after the second slave base station synchronization information is extracted is transmitted to the required terminal 1040 as a transmission packet. Send. However, at this time, the second slave base station 1012A has a slot obtained by subtracting slave base station synchronization information (in this case, “+1”) from the multiplex number N based on the clock signal supplied from the second terminal device 2022. After delaying the second slave base station transmission packet by several minutes, the second slave base station transmission packet is transmitted to the required terminal 1040 as a transmission packet. That is, in this case, the second slave base station 1012A transmits the packet received from the second terminal apparatus 2022 to the required terminal 1040 after delaying (N−1) slots.

  As a result, the second slave base station 1012A can transmit the transmission slot to the terminal 1040 at the same slot timing “1” as the accommodating apparatus 2000, that is, at the same slot timing “1” as the first master base station 1000A. The transmission slots of the first master base station 1000A and the second slave base station 1012A can be synchronized.

  Similarly, when the third slave base station 1013A receives the third slave base station transmission packet including the third slave base station synchronization information from the third terminal device 2023, the third slave base station 1013A receives the third slave base station transmission packet. The third slave base station synchronization information is extracted from the transmission packet for transmission, and the third slave base station transmission information after the third slave base station synchronization information is extracted is transmitted to the required terminal 1040 as a transmission packet. Send. However, at this time, the third slave base station 1013A determines the slave base station synchronization information from the multiplexing number N based on the clock signal supplied from the third termination device 2023 (in this case, “+ (N−2)”). The third slave base station transmission packet is delayed by the number of slots obtained by subtracting (), and the third slave base station transmission packet is transmitted to the required terminal 1040 as a transmission packet. That is, in this case, the third slave base station 1013A transmits the packet received from the third terminal device 2023 to the required terminal 1040 after delaying (N− (N−2) = 2) slots.

  As a result, the third slave base station 1013A can transmit the transmission slot to the terminal 1040 at the same slot timing “2” as the accommodating apparatus 2000, that is, at the same slot timing “2” as the first master base station 1000A. The transmission slots of the first master base station 1000A and the third slave base station 1013A can be synchronized.

(Device processing)
Each terminal 1040 executes reception processing of the TDMA frame transmitted from each slave base station by receiving and demodulating the received data at the slot timing assigned to itself.

[Uplink operation]
Next, uplink operation will be described with reference to FIG. The terminal 1040 transmits a signal at its own slot timing according to time division multiple access. Each of the slave base stations 1011A to 1013A receives the signal transmitted from the terminal 1040, performs demodulation processing, and sends the demodulation processing result to the terminal devices 2021 to 2023 connected thereto.

  Each of the terminal devices 2021 to 2023 transmits a demodulation processing result including control information (CI) to the coupler 2010 at its own slot timing determined by the optical network 1030A. The coupler 2010 combines the demodulation processing results transmitted from the terminal devices 2021 to 2023 and transmits the combined result to the accommodating device 2000. Accommodating apparatus 2000 sends the result of coupling received from coupler 2010 to master base station 1000A. The master base station 1000A combines the demodulation results of the slave base stations 1011A to 1013A from the combination result received from the accommodating device 2000.

  As described above, according to the first embodiment, the master base station transmits to each slave base station, the slave base station synchronization information indicating the delay of the slot with respect to the master base station in each slave base station. Since the base station corrects each slot timing based on the slave base station synchronization information, the master base station and each slave base station can be synchronized with a simple configuration and method. Thus, it is possible to provide a radio communication system that can prevent collision of transmission data and interference with adjacent slots in time division multiple access and can effectively use frequency resources. Furthermore, the transmission signals from the terminal can be received by a plurality of slave base stations, and the demodulation results at each slave base station can be combined at the master base station, so that the reception performance can be improved.

Embodiment 2.
Next, a second embodiment of the present invention will be described with reference to FIG. In the first embodiment, the slot timing difference between the accommodation device 2000 and each terminal device is used as the synchronization information. However, in the second embodiment, the transmission timing slot information indicating the transmission timing slot in each slave base station is synchronized. It is used as information.

  In the case of FIG. 5 also, as in the case of FIG. 3, the first termination device 2021 is delayed by 3 slots with respect to the accommodation device 2000, and the second termination device 2022 is delayed by 1 slot with respect to the accommodation device 2000. Is delayed by (N−2) slots with respect to the accommodation device 2000. The accommodation device 2000 delays 3 slots as slot timing difference information for the first termination device 2021, and slot timing for the second termination device 2022. The first master base station 1000A is notified in advance of one slot delay as the difference information and (N-2) slot delay as the slot timing difference information for the third terminal device 2023. Also, the first slave base station transmission slot is transmitted at the slot timing “0” of the accommodating device 2000, the second slave base station transmission slot is transmitted at the slot timing “1” of the accommodating device 2000, and the accommodating device It is assumed that a transmission slot for the third slave base station is transmitted at a slot timing “2” of 2000, and these slot timings are also notified from the accommodating apparatus 2000 to the first master base station 1000A in advance.

(Processing in master base station 1000A)
Based on the timing difference information notified from the accommodation device 2000 and the slot timing value in the accommodation device of each slave base station, the first master base station 1000A, the first slave base station 1011A, the second slave base The first slave base station synchronization information, the second slave base station synchronization information, and the third slave base station synchronization information for synchronizing the station 1012A and the third slave base station 1013A according to the following equations Generate.
(Synchronization information) = {N− (number of delay slots)
+ (Slot timing value at the accommodation device)} N remainder

  Each slave base station synchronization information indicates a transmission timing slot in each slave base station. According to the above equation, the first slave base station synchronization information is N remainder of {(N−3) +0} = N−3. Further, the second slave base station synchronization information is N remainder of {(N−1) +1} = 0. Further, in the third slave base station synchronization information, N remainder = 4 of {(N− (N−2)) + 2} is set as the third slave base station synchronization information.

  The first master base station 1000A supplies a clock to the accommodating device 2000 in the optical network 1030A and is for the first slave base station including the first slave base station synchronization information “N-3” described above. For the second slave base station including the transmission packet, the second slave base station synchronization information “0”, and for the third slave base station including the third slave base station synchronization information “4” Transmit packets are time-division multiplexed and serially transmitted. In this case, the transmission packet for the first slave base station is assigned to the slot with the slot number “0”, the transmission packet for the second slave base station is assigned to the slot with the slot number “1”, and the third slave base station The transmission packet for the station is assigned to the slot with the slot number “2”.

(Processing in optical network)
The processing in the optical network 1030A is the same as the operation of the first embodiment described above. That is, the accommodating apparatus 2000 sends a transmission packet for the first slave base station at the timing of the slot number “0”, sends a transmission packet for the second slave base station at the timing of the slot number “1”, 3 is transmitted at the timing of the slot number “2”. The coupler 2010 distributes the time division multiplexed data received from the first master base station 1000A to the first termination device 2021, the second termination device 2022, and the third termination device 2023.

  The first terminal device 2021 transmits to the first slave base station including the synchronization information for the first slave base station, which is data of the slot number “0” assigned to itself among the received time division multiplexed data. The packet is selected, and the selected transmission packet for the first slave base station is transmitted to the first slave base station 1011A. Also, the first termination device 2021 supplies its own operation clock to the first slave base station 1011A. Similarly, the second terminal device 2022 receives the second slave base station including the second slave base station synchronization information that is the data of the slot number “1” assigned to itself among the received time division multiplexed data. The transmission packet for the station is selected, and the selected transmission packet for the second slave base station is transmitted to the second slave base station 1012A. Also, the second terminal device 2022 supplies its operation clock to the second slave base station 1012A. Similarly, the third terminal device 2023 receives the third slave base station including the third slave base station synchronization information which is the data of the slot number “2” assigned to itself among the received time division multiplexed data. The transmission packet for the station is selected, and the selected transmission packet for the third slave base station is transmitted to the third slave base station 1013A. The third terminal device 2023 supplies its own operation clock to the third slave base station 1013A.

(Processing of each slave base station)
When the first slave base station 1011A receives the first slave base station transmission packet including the first slave base station synchronization information “N-3” from the first terminal device 2021, the first slave base station 1011A receives the first slave base station transmission packet. The first slave base station synchronization information is extracted from the base station transmission packet, and the first slave base station transmission information after the first slave base station synchronization information is extracted is used as a transmission packet. To 1040. However, at this time, the first slave base station 1011A uses the first slave base station transmission packet as a transmission packet at the transmission slot timing “N-3” indicated by the first slave base station synchronization information. Transmit to the required terminal 1040.

  Since the first slave base station 1011A is delayed by 3 slots with respect to the first master base station 1000A, the transmission data is transmitted at the transmission slot timing “N-3” in the first slave base station synchronization information. As a result, the transmission data can be transmitted at the same slot timing as the slot timing “0” that is the slot timing of the transmission data to the first slave base station 1011A in the first master base station 1000A. The transmission slots of the first master base station 1000A and the first slave base station 1011A can be synchronized.

  When the second slave base station 1012A receives the second slave base station transmission packet including the second slave base station synchronization information “0” from the second terminal device 2022, the second slave base station 1012A receives the second slave base station transmission packet. The second slave base station synchronization information is extracted from the transmission packet for transmission, and the second slave base station transmission information after the second slave base station synchronization information is extracted is transmitted to the required terminal 1040 as a transmission packet. Send. However, at this time, the second slave base station 1012A uses the second slave base station transmission packet as a transmission packet at the transmission slot timing “0” indicated by the second slave base station synchronization information. Transmit to terminal 1040.

  Since the second slave base station 1012A is delayed by one slot with respect to the first master base station 1000A, the transmission data is transmitted at the transmission slot timing “0” in the second slave base station synchronization information. As a result, the transmission data can be transmitted at the same slot timing as the slot timing “1” that is the slot timing of the transmission data to the second slave base station 1012A in the first master base station 1000A. The transmission slots of the master base station 1000A and the second slave base station 1012A can be synchronized.

  When the third slave base station 1013A receives the third slave base station transmission packet including the third slave base station synchronization information “4” from the third termination device 2023, the third slave base station The third slave base station synchronization information is extracted from the transmission packet for transmission, and the third slave base station transmission information after the third slave base station synchronization information is extracted is transmitted to the required terminal 1040 as a transmission packet. Send. However, at this time, the third slave base station 1013A uses the third slave base station transmission packet as a transmission packet at the transmission slot timing “4” indicated by the third slave base station synchronization information. Transmit to terminal 1040.

  Since the third slave base station 1013A is delayed by (N−2) slots with respect to the first master base station 1000A, the transmission data is transmitted at the transmission slot timing “4” in the third slave base station synchronization information. As a result, the transmission data can be transmitted at the same slot timing as the slot timing “2” which is the slot timing of the transmission data to the second slave base station 1012A in the first master base station 1000A. The transmission slots of the first master base station 1000A and the third slave base station 1013A can be synchronized.

  As described above, according to the second embodiment, the master base station transmits the slave base station synchronization information indicating the transmission timing slot in each slave base station to each slave base station, and each slave base station Since the transmission data is transmitted based on the synchronization information for stations, the master base station and each slave base station can be synchronized with a simple configuration and method, thereby enabling transmission data in time division multiple access. It is possible to provide a radio communication system capable of preventing frequency collisions and interference with adjacent slots and effectively using frequency resources. Furthermore, the transmission signals from the terminal can be received by a plurality of slave base stations, and the demodulation results at each slave base station can be combined at the master base station, so that the reception performance can be improved.

  In the above-described embodiment, EPON (Ethernet (registered trademark) Passive Optical Network), which is one of optical networks, is taken as an example of the wired transmission path. However, the wired transmission path is not limited to this, and other It may be an optical line or an electric line.

  In the above embodiment, the case where the timing difference of each slave base station is at least one slot has been described. However, the present invention is not limited to this, and there may be a slave base station having no timing difference.

  In the above embodiment, the case where the first slave base station transmits at slot timing 0, the second slave base station transmits at slot timing 1, and the third slave base station transmits at slot timing 2, Based on the received power at each slave base station of transmission data from a desired terminal, the slave base station to be transmitted to the terminal may be determined. In this way, the reception performance of the terminal can be improved.

  Further, although cases have been described with the above embodiment where each slave base station transmits at different slot timings, a configuration may be adopted in which a plurality of slave base stations transmit at the same slot timing, such as transmission diversity. In this way, the reception performance of the terminal can be improved.

  In the above embodiment, the demodulating process is performed in each slave base station, and then the demodulation result is synthesized in the master base station. However, each slave base station outputs a received digital baseband signal, The base station may be configured to perform demodulation processing after synthesizing digital baseband signals output from the slave base stations. Since the master base station and each slave base station are synchronized, the clock frequency deviation between each slave base station and the terminal is the same. Therefore, by synthesizing the digital baseband signal output from each slave base station at the master base station and performing demodulation processing, the accuracy of clock frequency deviation estimation can be improved and the received signal power to noise power ratio can be improved. Therefore, base station reception performance can be improved. Also, since the base station reception performance can be improved, the terminal scale for obtaining the desired base station reception performance can be reduced. Further, since it is not necessary to perform demodulation processing in each slave base station, each slave base station can be miniaturized.

  As described above, the wireless communication system according to the present invention is useful for a wireless communication system having a plurality of TDMA wireless base stations.

It is a figure which shows the structural example of the radio | wireless communications system concerning this invention. It is a figure which shows an example of the wired transmission path used for the radio | wireless communications system concerning this invention. 3 is a time chart of a downlink signal in the wireless communication system according to the first embodiment. 3 is a time chart of an uplink signal in the wireless communication system according to the first embodiment. 6 is a time chart of a downlink signal in the wireless communication system according to the second embodiment.

Explanation of symbols

1000A, 1000B Master base station 1011A, 1012A, 1013A Slave base station 1011B, 1012B, 1013B Slave base station 1020A, 1020B Cell 1030A Optical network 1040 Terminal 1050 IP network 2000 Accommodating device 2010 Coupler 2011 Optical transmission path 2021-2023 Terminating device

Claims (5)

A wireless communication system in which a TDMA master wireless base station and a plurality of slave base stations are connected to a point-multipoint via a wired transmission line,
The master radio base station transmits a time division multiplex packet including synchronization information for slot synchronizing each slave radio base station to a plurality of slave base stations,
Each slave radio base station changes a slot timing of a packet to be transmitted based on synchronization information included in the received packet. The synchronization information indicates a slot timing difference between the master radio base station and each slave base station,
2. The wireless communication system according to claim 1, wherein each slave radio base station transmits a packet by delaying the packet by the number of slots obtained by subtracting the synchronization information from the multiplexing number. The wired transmission path includes a receiving device connected to a master radio base station, a plurality of termination devices connected to the plurality of slave radio base stations, and a point-multipoint connection between the accommodation devices and the plurality of termination devices. And an optical transmission line
The slot timing difference is a slot timing difference between the accommodation device and each termination device,
The radio communication system according to claim 2, wherein the master radio base station supplies a clock to the accommodating device, and each termination device supplies a clock to each slave base station. The synchronization information indicates slot timing to be transmitted by each slave base station,
The wireless communication system according to claim 1, wherein each slave radio base station transmits a packet at a slot timing indicated by the synchronization information. The wired transmission path includes a receiving device connected to a master radio base station, a plurality of termination devices connected to the plurality of slave radio base stations, and a point-multipoint connection between the accommodation devices and the plurality of termination devices. And an optical transmission line
The synchronization information is
{Multiplex- (Slot timing difference between accommodating device and each terminating device) + (Slot timing value at accommodating device)}}
The radio communication system according to claim 4, wherein the master radio base station supplies a clock to the accommodating apparatus, and each termination apparatus supplies a clock to each slave base station.

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