JP2010041355A - Radio communication system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide radio communication system in which data amount per time is adjusted, and when a mobile station under communication is present near the boundary of a communication range of an adjacent base station, influence on communication of the adjacent base station is reduced and influence on communication of an own station is also reduced. <P>SOLUTION: The radio communication system includes: the mobile station 1 which moves on a line; and a plurality of base stations 2 connected so that radio communication becomes possible in communication ranges different from each other to the mobile station 1, wherein a communication frame comprising a plurality of time slots obtained by performing time division of a predetermined frequency used in the communication ranges of each base station 2 has a plurality of communication channels, and time slot positions of the communication channels are optionally set so that the positions are different from each other in the adjacent communication ranges. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to wireless communication between a mobile station and a base station, and more particularly to a train wireless communication system in which a plurality of base stations are provided along a railway line.

  In a conventional wireless communication system, the frequency used in the communication range of all base stations is the same, the frequency is time-divided into slots, and communication is performed by assigning different time slots to each base station. Yes. Therefore, even when the mobile station moves in the call area, there is no need to switch between transmission and reception frequencies, and processing associated with frequency switching is not required. Therefore, the time required for handoff is greatly reduced and communication interruption is prevented. (For example, refer to Patent Document 1).

JP 11-289576 A (page 4-5, FIGS. 1 and 2)

  In Patent Document 1, there are problems that time slots that can be used are fixedly limited for each base station and the amount of data per time is reduced, so that it takes time to exchange a large amount of information.

  The present invention has been made to solve these problems, and can adjust the amount of data per hour, and when a mobile station in communication exists near the boundary of the communication range of an adjacent base station, It is characterized in that the influence on the communication of the base station is reduced and the influence on the communication of the own station is also reduced.

  In order to solve the above problems, a wireless communication system according to the present invention includes a mobile station moving on a track and a plurality of bases connected to the mobile station so that wireless communication can be performed in different communication ranges. A communication frame comprising a plurality of time slots obtained by time-division of a predetermined frequency used in the communication range of each base station has a plurality of communication channels, and the communication channel time slot positions are adjacent to each other. It is possible to set differently in the range.

  According to the present invention, a communication frame composed of a plurality of time slots obtained by time-division of a predetermined frequency used in the communication range of each base station has a plurality of communication channels, and the communication channel has time slot positions adjacent to each other. Since it is possible to set differently in the range, when the mobile station in communication exists near the boundary of the communication range of the adjacent base station, the influence on the communication of the adjacent base station is reduced, It is also possible to reduce the influence on the communication of the own station.

  Embodiments of the present invention will be described below with reference to the drawings.

  In the embodiment of the present invention, a train radio communication system will be described in particular. First, the technology that is the premise of the present invention will be described.

  FIG. 10 is a configuration diagram of a train radio communication system in the base technology. As shown in FIG. 10, the mobile station 1 (mobile station 1a, mobile station 1b) mounted on a train moving on the track and installed along the track so that wireless communication with the mobile station 1 is possible. LCX cable (Leaky Coaxial Cable: leaky coaxial cable) installed as an antenna of the base station 2 for communication between the base station 2 (base station 2a, base station 2b,..., Base station 2n) and the mobile station 1 ) 3 (LCX3a, LCX3b,..., LCX3n) and a central station 4 that controls the mobile station 1 and the base station 2, and the mobile station 1 is an interzone (zone) that is a communication range of each base station 2. a, zone b,..., zone n).

  FIG. 11 is a configuration diagram of a frame transmitted from the mobile station 1 to the base station 2 according to the related art. As shown in FIG. 11, one or more time slots are fixedly assigned to each CH (communication channel). That is, different time slots in the frame are fixedly assigned to each base station. Thus, since the frame of FIG. 11 is used for communication between the mobile station 1 and the base station 2 in each zone, the usable time slots are limited.

  Next, the operation in the conventional wireless communication system will be described using FIG. 10 and FIG.

  As shown in FIG. 10, the communication between the mobile station 1 and the base station 2 uses the same frequency in each zone, the frequency f1 from the mobile station 1 to the base station 2, and the mobile station from the base station 2 1 is communicating at the frequency F1. The mobile station 1 and the base station 2 exchange a signal for identifying the zone and a signal for specifying the mobile station 1, so that the mobile station 1 moves in the zone where the own station is located, and the base station 2 moves Recognizes the station 1 station. The base station 2 gives permission to use a communication channel (communication CH) that can be used to the mobile station 1 that is stationed on its own station, or is used by means for recognizing a communication channel that the mobile station 1 can use. A communication channel to be determined is determined, and data is transmitted to the base station 2.

  For example, when the mobile station 1a in communication with the base station 2a in the zone a moves to the vicinity of the boundary between the zone b and the zone b adjacent to the zone a, the base station 2a in the zone a that has been communicating until then is changed to the mobile station 1a. It is detected that the mobile station 1a has moved due to the disappearance of the identification signal received from the mobile station 1 and the time slots 1 and 2 used by the mobile station 1a are released. On the other hand, the mobile station 1a detects that its own station has entered the zone b by receiving a signal from the base station 2b that is the destination base station, or the base station 2b By receiving the signal, it is detected that the mobile station 1a has entered, and exchange of the zone identification signal and the mobile station identification signal is started between the base station 2b and the mobile station 1a. When the base station 2b gives the presence permission to the mobile station 1a that has entered the zone b, the use permission of the usable communication CH is given to the mobile station 1a, or the mobile station 1a can be used. The communication channel to be used is determined by means for recognizing the communication channel, and the mobile station 1a transmits data to the base station 2b using the determined communication channel.

  When a mobile station in communication moves to an adjacent zone, make sure that the time slot of the communication channel used by the mobile station does not overlap the time slot of the communication channel used in the destination zone. The base station of the destination zone blocks the time slot in advance so that it cannot be used, or the base station of the source zone blocks the time slot so that it cannot be used.

  As described in Patent Document 1, the wireless communication system of the base technology described above has the same frequency used in the communication range of all base stations, and assigns different time slots to each base station for communication. Like to do. Therefore, even when the mobile station moves between zones, it is not necessary to switch the frequency used for transmission / reception, so that the time required for handoff can be greatly shortened and communication interruption can be prevented.

  In addition, the base station grants the use permission of the usable communication channel to the mobile station existing in the own station, or determines the communication channel to be used by means for recognizing the usable communication channel by the mobile station. Since the data is transmitted to the base station, the usable time slots are not limited to each base station, and the data amount per time can be adjusted.

  However, when the mobile station in communication with the base station is near the boundary of the communication range of the adjacent base station, the communication quality of the mobile station communicating with the adjacent base station is affected by the overreach from the mobile station. There was a problem such as giving. Therefore, in order to avoid overreach, it is necessary to interrupt communication near the boundary of the communication range of adjacent base stations.

  Also, if there is a time slot that uses control information for on-line management in the communication range of each base station in a communication frame consisting of time slots with time-divided frequencies, the control information is normal at the base station. There was a problem such as being unable to receive.

  The present invention is for solving these problems, and the solution will be described in detail below.

<Embodiment 1>
FIG. 1 is a configuration diagram of a radio communication system according to Embodiment 1 of the present invention. As shown in FIG. 1, the wireless communication system according to the first embodiment includes a mobile station 1 (mobile station 1a, mobile station 1b, mobile station 1c,..., Mobile station 1n) moving on a track, and a mobile station. 1, a base station 2 (base station 2a, base station 2b, base station 2c,..., Base station 2n) connected so that wireless communication can be performed in different communication ranges, and mobile station 1 LCX cables 3 (LCX3a, LCX3b, LCX3c,..., LCX3n) installed as antennas for the base station 2 and the central station 4 for controlling radio communication between the mobile station 1 and the base station 2, The mobile station 1 passes through zones (zone a, zone b, zone c,..., Zone n) that are communication ranges of the base stations 2.

  As shown in FIG. 1, the communication between the mobile station 1 and the base station 2 uses the same frequency in each zone, the frequency f1 from the mobile station 1 to the base station 2, and the mobile station from the base station 2 1 is communicating at the frequency F1. In addition, a frame (communication frame) used at the time of communication is different in each adjacent zone (each base station).

  FIG. 2 is a block diagram of the mobile station 1 according to the first embodiment of the present invention. As shown in FIG. 2, the mobile station 1 includes a receiver 21 that receives radio data transmitted from the base station 2, a transmitter 22 that transmits radio data from the mobile station 1 to the base station 2, and a receiver 21. The reception data processing unit 23 that processes the data received by the mobile station 1, the transmission data processing unit 24 that processes the data transmitted from the transmitter 22, the control unit 25 that controls the mobile station 1, and the presence of the mobile station 1 A position detection unit 26 that detects a position and a frame control unit 27 that controls a data frame to be transmitted while holding a table that defines a frame to be used for each zone as shown in FIG.

  FIG. 3 is a block diagram of the base station 2 according to Embodiment 1 of the present invention. As shown in FIG. 3, the base station 2 receives a radio data from the mobile station 1 via the LCX 3 and a receiver 31 that transmits radio data from the base station 2 to the mobile station 1 via the LCX 3. Machine 32, reception data processing unit 33 for processing data received by receiver 31, transmission data processing unit 34 for processing data transmitted from transmitter 32, management of mobile station 1 on the line, and base station 2 And a frame control unit 36 that controls a data frame received by holding a table that defines a frame to be used for each zone as shown in FIG. 6 to be described later.

  FIG. 4 is a block diagram of the central office 4 according to Embodiment 1 of the present invention. As shown in FIG. 4, the central station 4 receives a data transmitted from the base station 2 and processes the data, and a transmission data processing unit 42 that processes data to be transmitted to the base station 2. And a control unit 43 that performs management of the mobile station 1, management of the base station 2, control of data, and the like in the entire wireless communication system.

  Next, the operation of the wireless communication system according to the first embodiment will be described. For example, description will be made assuming that each of the frame control unit 27 of the mobile station 1 and the frame control unit 36 of the base station 2 uses the frame shown in FIG. 5 and the table shown in FIG.

  In FIG. 1, when the mobile station 1a located in the zone a receives the signal identifying the zone a transmitted from the base station 2a, the frame control unit 27 of the mobile station 1a uses the frame table shown in FIG. A transmits data to the base station 2a. On the other hand, when the mobile station 1b located in the zone b receives the signal identifying the zone b transmitted from the base station 2b, the mobile station 2b changes the frame B to the frame B based on the frame table shown in FIG. To transmit data to the base station 2b.

  FIG. 5 is a configuration diagram of a frame transmitted from the mobile station 1 to the base station 2 according to Embodiment 1 of the present invention. As shown in FIG. 5, there are a frame A and a frame B as frames transmitted from the mobile station 1 to the base station 2. For example, as shown in FIG. 1, frame A is used in zone a, frame B is used in zone b, and different frames are used in adjacent zones. The frame has time-slotted time slots, and each time slot is assigned to each communication channel. In the present embodiment, the slots that can be used are not limited in the base station as in the prior art, and can be set by using or not using a communication channel. That is, a frame composed of a plurality of time slots obtained by time-division of a predetermined frequency used in the communication range (zone) of each base station 2 has a plurality of communication channels, and the time slot positions of the communication channels are adjacent to each other. It is possible to set differently in the communication range. It is assumed that communication channels are assigned to each zone in the same manner as in the above-described base technology.

  FIG. 6 is a diagram showing a frame table held in the mobile station 1 and the base station 2 according to Embodiment 1 of the present invention, held in the frame control unit 27 of the base station 1 and the frame control unit 36 of the base station 2. Has been. As shown in FIG. 6, for example, by setting the frame A in the zone a and the frame B in the zone b, the adjacent zones are set to use different frames.

  As shown in FIG. 5, CH1 is set in slots 1 and 2 in frame A, and is set in slots 3 and 4 in frame B. With this setting, even when the mobile station 1a approaches the boundary with the zone b and the transmitted wave of the mobile station 1a reaches the base station 2b (over reach), the mobile station 1a and the mobile station 1b Since the frames and time slots used by each of the mobile stations 1 and 2 are different, it is avoided that the communication of the mobile station 1a interferes with the communication of the mobile station 1b, and the influence on the communication of the own station is reduced.

  Further, when the mobile station 1a receives a signal for identifying the zone b from the base station 2b, that is, moves to the zone b, the mobile station 1a transmits it in the frame B. At this time, there may be an overreach from the moved mobile station 1a to the source zone a, but since the frames and time slots used in the zone b and the zone a are different, the mobile station 1a existing in the zone a is moved to. Communication interference can be avoided.

  From the above, it is possible to arbitrarily set the frames used in the adjacent zones to be different and the time slot positions of the communication channels assigned to the frames to be different in the adjacent zones. When the mobile station exists near the boundary of the communication range of the adjacent base station, the influence on the communication of the adjacent base station can be reduced, and the influence on the communication of the own station can also be reduced.

  In the first embodiment of the present invention, communication is performed using two types of frames. However, if the frames in adjacent zones are not the same, the same effect can be obtained even if communication is performed using a plurality of frames. . Further, the reserved CH shown in FIG. 5 is a reserved CH, and is used in the adjacent zone, so that it cannot be used in advance so as not to be affected by overreach.

<Embodiment 2>
The second embodiment of the present invention is characterized in that the central station 4 that controls the wireless communication between the mobile station 1 and the base station 2 can arbitrarily set the time slot position of the communication channel. Since other configurations are the same as those of the first embodiment, description thereof is omitted here.

  FIG. 7 is a block diagram of the central office 4 according to the second embodiment of the present invention. As shown in FIG. 7, the central station 4 of the present embodiment 2 includes a frame management unit 44 that manages and controls the frame table held by the mobile station 1 and the base station 2. Other configurations and operations are the same as those in the first embodiment.

  FIG. 8 is a diagram showing a frame table held in the mobile station 1 and the base station 2 according to Embodiment 2 of the present invention. As shown in FIG. 8, in the frame table, a frame type identifier and a frame are associated with each other. Each of the frame controller 27 of the mobile station 1 and the frame controller 36 of the base station 2 holds a frame table as shown in FIG.

  The frame management unit 44 transmits the frame type identifier of the frame table shown in FIG. 8 held by the frame control unit 36 of the base station 2 to each base station, thereby transmitting the frame from the mobile station 1 to the base station 2. Specify the frame to be used. Each base station 2 determines allocation of a time slot and a communication channel of a frame transmitted from a mobile station existing in the zone of the local station, based on the frame type identifier designated by the central station 4. The mobile station 1 receives the frame type identifier from each base station 2 for each zone, and transmits data to the base station 2 using a frame corresponding to the same frame type identifier.

  Further, the mobile station 1 may hold a frame table as shown in FIG. 9 in advance, and may use a frame type identifier corresponding to the zone where the line is located.

  FIG. 9 is a diagram showing a frame table held in the mobile station 1 according to the second embodiment of the present invention. As shown in FIG. 9, in the frame table, a frame type identifier corresponding to each zone is associated and held in the frame control unit 27 of the mobile station 1. In the zone a, the base station 2a receives data from the mobile station 1 in the frame A designated by the frame type identifier 1 from the central station 4 based on the frame table of FIG. On the other hand, the mobile station 1a transmits data in the frame A designated by the frame type identifier 1 based on the frame table of FIG.

  From the above, since the central station 4 can arbitrarily set the time slot position of the communication channel for each zone of the base station 2, the degree of freedom of communication channel assignment for reducing communication interference is increased. be able to.

It is a block diagram of the radio | wireless communications system by Embodiment 1 of this invention. It is a block diagram of the mobile station by Embodiment 1 of this invention. It is a block diagram of the base station by Embodiment 1 of this invention. 1 is a block diagram of a central office according to Embodiment 1 of the present invention. FIG. It is a block diagram of the flame | frame transmitted to the base station from the mobile station by Embodiment 1 of this invention. It is a figure which shows the frame table hold | maintained at the mobile station and base station by Embodiment 1 of this invention. It is a block diagram of the central office by Embodiment 2 of this invention. It is a figure which shows the frame table hold | maintained at the mobile station and base station by Embodiment 2 of this invention. It is a figure which shows the frame table hold | maintained at the mobile station by Embodiment 2 of this invention. It is a block diagram of the conventional wireless communication system. It is a block diagram of the frame transmitted to the base station from the conventional mobile station.

Explanation of symbols

  1 mobile station, 2 base station, 3 LCX cable, 4 central station, 21 receiver, 22 transmitter, 23 received data processing unit, 24 transmission data processing unit, 25 control unit, 26 position detection unit, 27 frame control unit, 31 receiver, 32 transmitter, 33 received data processing unit, 34 transmitted data processing unit, 35 control unit, 36 frame control unit, 41 received data processing unit, 42 received data processing unit, 43 control unit, 44 frame management unit.

Claims (2)

A mobile station moving on the track,
A plurality of base stations connected to the mobile station to enable wireless communication in different communication ranges;
In a wireless communication system comprising:
A communication frame composed of a plurality of time slots obtained by time-sharing a predetermined frequency used in the communication range of each base station has a plurality of communication channels, and the time slot positions of the communication channels are in the adjacent communication ranges. A wireless communication system, characterized in that each can be set differently.   The wireless communication system further includes a central station that controls the wireless communication between the mobile station and the base station, and the central station can arbitrarily set the time slot position of the communication channel. The wireless communication system according to claim 1, wherein:

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