JP2010034824A - Control station device, digital radio communication system, and control method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a control station device that widens a communication area using one carrier frequency, and enables a mobile station to receives transmission information normally even in an area wherein respective base stations have overlapping communication areas. <P>SOLUTION: The control station device is used for a digital radio communication system which includes a plurality of base station devices communicating with a plurality of mobile station devices using one carrier frequency, and the control station device controlling the plurality of base station devices, wherein each of the base station devices synchronizes frame timings of cluster frames for transmitting a synchronizing signal among the plurality of base stations, and transmits the synchronizing signal with cluster frames in each sequence previously allocated to the own base station among the synchronized cluster frames. The control station device includes a selection device which selects one of the plurality of base station devices and transmits a transmission signal through the selected base station device. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a digital radio communication system used for a taxi or the like, and more particularly to a technology of a digital radio communication system that can widen a service area, that is, a communication area using one carrier frequency.

In recent years, digital wireless communication systems using digital wireless communication wireless communication (see Non-Patent Document 1) have become widespread in wireless communication systems used for taxis and the like. In this digital wireless communication system, one or a small number of carrier frequencies are assigned to each taxi company. Note that the number of carrier frequencies allocated to a taxi company is determined by the number of taxis owned by the taxi company, that is, the number of mobile stations. For this reason, if the number of mobile stations owned is small, the taxi company has difficulty in obtaining a plurality of carrier frequencies even when the service area is large.
Therefore, in digital taxi radio, it is required to widen the service area, that is, the communication area, using one carrier frequency. Further, in a digital wireless communication system, it is required that a data signal indicating position information of a mobile station can be transmitted and received even during a period in which voice communication is performed between the mobile station and the base station.

  By the way, a half duplex method and a simplex method are known as communication methods used in digital taxi radio. In the half-duplex method, transmission from the base station (downlink) and transmission from the mobile station (uplink) use different frequencies. For example, the base station always transmits a downlink signal (the regular transmission type, which includes a continuous transmission type and an intermittent transmission type). The mobile station is a system that receives a signal from a base station and transmits an uplink signal in synchronization with the base station. Since the mobile station is synchronized with the base station, it can be received by the base station if it transmits only the minimum necessary data.

  On the other hand, in the simplex scheme, there are cases where the uplink and downlink frequencies are the same (ie, one frequency) and different (ie, two frequencies). Both base stations and mobile stations transmit only when necessary. That is, it is an emergency delivery type. Therefore, when receiving, the mobile station needs to synchronize with the transmission side every time. When transmitting, the mobile station needs to transmit a signal to synchronize prior to the data to be transmitted. is there. Therefore, communication traffic tends to be lower in the simplex scheme than in the half duplex scheme. Therefore, when transmitting a data signal, the half duplex method is more advantageous than the simplex method.

  Here, in order to widen the communication area, it is necessary to install a plurality of base stations. That is, since each base station has each communication area, this digital radio communication system has a wide communication area as a whole. For example, as shown in FIG. 6, the digital wireless communication system includes a base station A and a base station B. The base station A and the base station B are controlled by the control station.

Next, the problem when the half-duplex scheme is used in the case of two base stations will be described. In the case of the half duplex method, in order to always maintain synchronization between the base station and the mobile station, in the case of the continuous transmission type continuous transmission type, a downlink signal is always transmitted from the base station. In the case of the continuous transmission type of the continuous transmission type, if two base stations transmit at the same carrier frequency at the same time, the mobile station in the overlapping area (for example, the mobile station E in FIG. 6) is synchronized with the base station. It becomes impossible to take and communication becomes impossible. In the case of the half duplex method, even in the case of the intermittent transmission type, the same phenomenon as described above occurs when the timings of transmission from two base stations overlap. Therefore, there is a problem that the half-duplex scheme cannot be used when areas are overlapped by a plurality of base stations.
Therefore, when the communication area is widened and a plurality of base stations are installed, a simplex scheme that transmits only when necessary is used. And it communicated by the system shown to the following (A1) to (A3) using the simplex system.

(A1) The downlink signal transmitted from the base station is an emergency transmission. That is, the downlink signal from the base station is transmitted as necessary during voice call or data communication.
(A2) Similar to the base station, the mobile station transmits an uplink signal as necessary during a voice call or data call.
(A3) One control station controls signals transmitted from a plurality of base stations.

  In the digital wireless communication system satisfying the above conditions, when the carrier frequencies transmitted from two or more adjacent base stations are the same, and when each base station transmits at an independent timing, when the transmission timing overlaps, There arises a problem that the signals of each other interfere with each other. At this time, since the mobile station cannot receive the signal from the base station, there also arises a problem that it cannot transmit. In addition, there is also a problem that, in order to prevent the transmission signals from colliding with each other, the transmission of the other must be stopped during the transmission period of one.

For example, in FIG. 6, when base station A and mobile station A or base station B and mobile station H perform a voice call or data communication, the transmission time chart is as shown in FIG. Become. For example, the base station A transmits during the period from time t1 to t2. Next, mobile station A transmits during the period from time t3 to t4. Next, base station A transmits in the period from time t5 to t6. Next, the base station B transmits in the period from time t7 to t8. And the mobile station H transmits in the period from the time t9 to t10.
The Japan Radio Industry Association, “Narrowband Digital Communication System (SCPC / FDMA) Standard ARIB STD-T61 Version 1.2”, issued on November 30, 2005

Here, an example of the use of a frame when the base station A is transmitting is shown in FIG. In FIG. 8, numerals indicate frame numbers that repeat from 0 to 3. From FIG. 8, the base station A transmits in all frames. The method of using the frame when the mobile station is transmitting is the same as the method of using the base station in FIG.
As described above, since voice signals are transmitted and received using all frames, there is a problem that data communication cannot be performed during a voice call. There is also a problem that the other base station cannot transmit during the period in which the other base station is communicating with the mobile station. In addition, when a plurality of base stations transmit transmission information at independent timings and overlap occurs in the transmission information transmission period, there is a problem that the mobile station may not be able to receive the transmission information normally. there were.

  The present invention has been made in view of such circumstances, and the object thereof is to widen the communication area by using one carrier frequency, and even in a region where the communication areas overlap in each base station, the present invention can be moved. It is an object of the present invention to provide a control station apparatus, a digital radio communication system, and a control method that enable a station to normally receive transmission information. Also, to provide a control station apparatus, a digital radio communication system, and a control method capable of enabling data communication even during a period in which any base station is performing voice communication. Objective.

  The present invention has been made to solve the above-described problems. The invention according to claim 1 is directed to a plurality of base station apparatuses that communicate with a plurality of mobile station apparatuses using a single carrier frequency, and the plurality of base station apparatuses. A control station device that controls the base station device, and each of the base station devices synchronizes the frame timing of a cluster frame for transmitting a synchronization signal among the plurality of base station devices, and the synchronized cluster In a frame, a control station apparatus used in a digital radio communication system that transmits a synchronization signal in a cluster frame in each order assigned in advance to its own base station apparatus, and any one of the plurality of base station apparatuses A control station apparatus comprising: a selection apparatus that selects a base station apparatus and transmits a transmission signal via the selected base station apparatus.

  According to a second aspect of the present invention, the transmission signal includes a voice signal, and the selection apparatus selects a first base station apparatus that transmits a first voice signal from the plurality of base station apparatuses. An audio signal selection device, wherein the audio signal selection device selects the audio signal completion signal indicating that the selected first base station device has completed transmission of the first audio signal. In response to reception from the first base station apparatus, a second base station apparatus that transmits a second audio signal can be selected from the plurality of base station apparatuses. A control station apparatus according to claim 1.

  According to a third aspect of the present invention, the transmission signal includes a data signal, and the selection device selects a third base station device that transmits the first data signal from the plurality of base station devices. A data signal selection device, wherein the data signal selection device selects the data signal completion signal indicating that the selected third base station device has completed transmission of the first data signal. According to reception from the third base station apparatus, a fourth base station apparatus that transmits a second data signal can be selected from the plurality of base station apparatuses. A control station apparatus according to claim 1 or claim 2.

  According to a fourth aspect of the present invention, the cluster frame has a plurality of predetermined frames, and each of the plurality of base station apparatuses transmits the synchronization signal in a part of the plurality of frames. And transmitting a voice signal in which the amount of information is compressed in a part of the plurality of frames that do not transmit the synchronization signal, and any of the plurality of frames includes a synchronization signal and a voice signal. The data signal is transmitted in a frame that is not transmitted, or the data signal is transmitted together with the synchronization signal in a frame in which the base station apparatus transmits the synchronization signal. It is a control station apparatus of description.

  The invention according to claim 5 is a digital radio communication system having a plurality of base station apparatuses that communicate with a plurality of mobile station apparatuses using one carrier frequency, and a control station apparatus that controls the plurality of base station apparatuses. In each of the plurality of base station devices, a synchronization unit that synchronizes the frame timing of a cluster frame that transmits a synchronization signal between the plurality of base station devices, and a cluster frame that is synchronized by the synchronization unit A transmission unit that transmits a synchronization signal in a cluster frame in each order that is assigned to the base station device in advance, and the control station device is any one of the plurality of base station devices. A digital wireless communication system comprising: a selection device that selects a device and transmits a transmission signal via the selected base station device.

  The invention according to claim 6 includes a plurality of base station apparatuses that communicate with a plurality of mobile station apparatuses using a single carrier frequency, and a control station apparatus that controls the plurality of base station apparatuses, The base station device synchronizes the frame timing of a cluster frame for transmitting a synchronization signal among the plurality of base station devices, and in the synchronized cluster frame, for each order previously assigned to the own base station device. A control method used in a control station apparatus used in a digital radio communication system that transmits a synchronization signal in a cluster frame, wherein one of the plurality of base station apparatuses is selected, and the selected base station is selected. A control method comprising a selection procedure for transmitting a transmission signal via a station apparatus.

According to the present invention, a control station device that controls a plurality of base station devices that communicate with a plurality of mobile station devices using a single carrier frequency is selected by the selection device so that any one of the plurality of base station devices A station apparatus is selected, and a transmission signal is transmitted through the selected base station apparatus. Thereby, since only one base station transmits a transmission signal among a plurality of base station apparatuses, a plurality of base station apparatuses do not transmit a transmission signal redundantly. Therefore, the mobile station apparatus can normally receive the transmission signal transmitted from one base station apparatus.
In addition, each base station apparatus synchronizes the frame timing of a cluster frame for transmitting a synchronization signal among a plurality of base stations, and in the synchronized cluster frame, the base station apparatus for each order assigned to the base station in advance. A synchronization signal is transmitted in a cluster frame. As a result, the synchronization signals to be transmitted do not overlap between the base station apparatuses. Therefore, it is possible to widen the communication area using one carrier frequency, and it is possible to perform communication even in an area where the communication areas overlap in each base station apparatus.

<Outline of this embodiment>
First, an outline of the present embodiment will be described. The base station according to the present embodiment is a regular transmission type intermittent transmission type, in which two base stations alternately transmit a synchronization signal to maintain synchronization between the base station and the mobile station. In this embodiment, a case where there are two base stations will be described. The interval for transmitting the synchronization signal from the base station is set with a cluster frame as one unit. In the case of two base stations, one base station transmits, for example, a synchronization signal for each cluster frame (the interval may be one cluster frame or more). The other base station transmits a synchronization signal in an empty cluster frame.

  Each base station uses the GPS (Global Positioning System) PPS (Pulse Per Second) signal as a reference signal to correct the frame timing, that is, the boundary between the cluster frames so that the transmission timings do not overlap each other. To. As for the frame timing correction method using the PPS signal, the base station generates a symbol timing signal and a frame timing signal based on an internal oscillator. Further, the frame timing signal is corrected with the accuracy of the symbol interval at the timing of the PPS signal from the GPS. Further, when correcting the frame timing, it is performed at a timing when the base station does not transmit.

<Configuration of this embodiment>
Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic block diagram showing the configuration of a digital radio communication system according to an embodiment of the present invention. Here, a case will be described in which the digital radio communication system has the control station 1 and two base stations of the base station 2 and the base station 3. In addition, the control station 1 is an apparatus set to the control station demonstrated using FIG. 6, for example. Further, the base station 2 and the base station 3 are devices respectively installed in the base station A and the base station B described with reference to FIG. In this embodiment, a case of an FDMA (Frequency Division Multiple Access) system using an SCPC (Single-Channel Per Carrier) system will be described as a communication system of each base station.

  The control station 1 and the base station 2 are connected via a data communication line 4-2 and a voice communication line 5-2. The data communication line 4-2 and the voice communication line 5-2 are a dedicated line, an ADSL (Asymmetric Digital Subscriber Line) line, an optical communication line, and the like. Similar to the control station 1 and the base station 2, the control station 1 and the base station 3 are connected via a data communication line 4-3 and a voice communication line 5-3.

  The control station 1 includes a control device 11, a voice communication device 12-2, a voice communication device 12-3, and a selection device 13. The control device 11 communicates data signals with the base station 2 and the base station 3 via the data communication line 4-2 and the data communication line 4-3. The voice communication device 12-2 communicates voice signals with the base station 2 through the voice communication line 5-2. The voice communication device 12-2 has, for example, a microphone and a speaker. Similar to the voice communication device 12-2, the voice communication device 12-3 communicates voice signals with the base station 3 via the voice communication line 5-3. The selection device 13 selects any one of the plurality of base stations (here, the base stations 2 and 3), and transmits a transmission signal via the selected base station. The transmission signal is a signal including an audio signal or a data signal. Details of the selection device 13 will be described later.

  Since the base station 2 and the base station 3 have the same configuration, the configuration of the base station 2 will be described here. The base station 2 includes a synchronization unit (GPS unit) 21, a transmission unit (TX unit) 22, a reception unit (RX unit) 23, a reference signal generation unit (OXCO (Oven Controlled Xtal Oscillator) unit) 24, data The communication unit 25 includes a voice communication unit 26, a GPS antenna 201, a transmission antenna 202, and a reception antenna 203. The transmission unit 22 and the reception unit 23 are connected by a plurality of signal lines 27.

The synchronization unit 21 receives a GPS signal from a GPS satellite via the GPS antenna 201. The synchronization unit 21 outputs the received GPS signal to the transmission unit 22 and the reception unit 23 to synchronize the frame timing of the cluster frame among the plurality of base stations. The data communication unit 25 communicates data signals with the control station 1 via the data communication line 4-2. The voice communication unit 26 communicates voice signals with the control station 1 via the voice communication line 5-2.
The reference signal generation unit 24 outputs the generated reference signal to the transmission unit 22 and the reception unit 23. The reference signal generation unit 24 is, for example, a temperature controlled crystal oscillator (Oven Controlled Xtal Oscillator).

  The transmission unit 22 transmits the data signal received by the data communication unit 25 from the control station 1 or the voice signal received by the voice communication unit 26 from the control station 1 based on the reference signal generated by the reference signal generation unit 24. Via 202. That is, the transmission unit 22 transmits transmission information that is a data signal or a voice signal from the control station 1 to the mobile station. In the plurality of cluster frames synchronized by the synchronization unit 21, the transmission unit 22 transmits a synchronization signal in a cluster frame in each order assigned to the own base station in advance.

  The receiving unit 23 receives a data signal or an audio signal received via the receiving antenna 203 based on the reference signal generated by the reference signal generating unit 24. Then, the receiving unit 23 transmits the received data signal or audio signal to the control station 1 via the data communication unit 25 or the audio communication unit 26. That is, the reception unit 23 transmits reception information that is a data signal or a voice signal from the mobile station to the control station 1.

<Configuration of Transmitter 22>
Next, the configuration of the transmission unit 22 will be described in detail. The transmission unit 22 includes a transmission offset value storage unit 221. In this transmission offset value storage unit 221, an offset value from a reference frame is stored in advance so that transmission timing does not overlap among a plurality of base stations. That is, the transmission offset value storage unit 221 stores in advance offset values that do not overlap among a plurality of base stations.

  When transmitting, the transmission unit 22 transmits a cluster frame calculated by adding the offset value read from the transmission offset value storage unit 221 to a reference frame, thereby transmitting a synchronization signal between base stations. Make sure that the transmission timing does not overlap. That is, the transmission unit 22 transmits a synchronization signal in a cluster frame in each order based on the offset value read from the transmission offset value storage unit 221 in the cluster frame synchronized by the synchronization unit 21.

  The reference frame is determined in advance for each period defined in common for a plurality of base stations, for example, as frame 0 of the first cluster frame in that period. Further, this period is at least longer than the time length of the cluster frame corresponding to the number of base stations. Thereby, in this period, each base station can have at least one cluster frame corresponding to its own base station. Thereby, each base station can transmit a reference signal using a cluster frame corresponding to the base station. In this way, the transmission unit 22 uses a half-duplex method and transmits as a regular transmission type intermittent transmission type. And this transmission part 22 transmits as follows.

  The transmission unit 22 sets the interval at which the synchronization signal is intermittently transmitted from the base station to the mobile station as a unit of cluster frames, and transmits at least for each cluster frame of the number of base stations. For example, if the number of base stations is 2, the transmission unit 22 of the base station transmits at least every 2 cluster frames. That is, if the number of base stations is n (n is an arbitrary natural number), the transmission unit 22 of the base station transmits at least every n cluster frames.

  The transmission unit 22 sets the number of frames for intermittent transmission of the synchronization signal from the base station to at least one frame, and at most reduces the number of frames of one cluster frame to the number of frames used for voice communication. For example, when two frames are used for a voice call, the number of transmission frames for intermittent transmission is a maximum of two frames because one cluster frame is four frames. This is because, for example, intermittent transmission from the base station 3 is possible even when an audio signal is transmitted from the base station 2.

  Further, the transmission unit 22 corrects the frame timing at a timing at which the own station does not transmit (a timing at which another base station transmits). Further, when correcting the GPS PPS signal as a reference signal, the transmission unit 22 performs the above-described accuracy of correcting the frame timing on a symbol basis. Further, the transmission unit 22 corrects the frame timing error between the base stations so as to be within the range of the number of guard bits in the frame.

  In a plurality of base stations, it is not necessary to intermittently transmit synchronization signals from all the base stations, and it is possible to stop the transmission function of any base station and make the base station a reception-only base station (For example, to eliminate the up / down imbalance). At this time, the interval at which the synchronization signal is intermittently transmitted can be determined from the number of base stations having a transmission function.

<Operation of base station>
By the way, each cluster frame has four frames (refer to cluster frames and frames in FIG. 2 described later). The operation of the base station in the system using this frame configuration will be described. For example, frame 0 of cluster frame 0 at a certain timing is set as the synchronization signal reference timing (the reference frame described above), and the synchronization signal transmission interval is set to 8 frames (2 cluster frames). When the offset value of the base station A is “0” and the offset value of the base station B is “4”, the synchronization signal periodically transmitted from the base station A and the base station B (see reference numeral TX in FIG. 2) As shown in FIG.

  As shown in FIG. 2, the base station A transmits a synchronization signal using frame 0 of cluster frame 0 and frame 0 of cluster frame 2. On the other hand, the base station B transmits a synchronization signal using frame 0 of cluster frame 1 and frame 0 of cluster frame 3. That is, the base station A and the base station B each transmit a synchronization signal in a predetermined frame 0 of the cluster frame for every two cluster frames that do not overlap in each base station.

  As described above, the frame timings of the base stations using the same carrier frequency adjacent to each other are synchronized without stopping the transmission of the base stations of each other and preventing the transmission signals from colliding with each other. Also, in order to prevent the synchronization signal timing transmitted from each base station from overlapping, the synchronization signal reference timing and the synchronization signal transmission interval are determined, and each base station has a different offset value and is offset from the reference timing. The synchronization signal is transmitted in the frame with the value added. And the mobile station in the service area of base station A and base station B can transmit synchronizing with a base station.

  In the state shown in FIG. 2, when voice transmission is performed from the base station A to the mobile station, it is as shown in FIG. Here, the amount of information of the audio signal for one cluster frame time, that is, the amount of information of the audio signal that can be transmitted in 4 frames is compressed to the amount of information that can be transmitted in 2 frames, and frames 2 and 3 are transmitted. Shall be sent using As described above, a technique disclosed in Japanese Patent Application Laid-Open No. 2006-279778 is known as a technique for compressing and transmitting an audio signal.

  With reference to FIG. 3, a frame configuration as an example when an audio signal is transmitted will be described. Similar to FIG. 2, the base station A transmits a synchronization signal in frame 0 of cluster frame 0. That is, frame 0 of cluster frame 0 is a synchronization signal transmission frame of base station A. Base station B transmits a synchronization signal in frame 0 of cluster frame 1. That is, frame 0 of cluster frame 1 is a synchronization signal transmission frame of base station B. Thereafter, the base station A and the base station B alternately transmit a synchronization signal at frame 0 in the cluster frame alternately for each cluster frame. Then, in frames 2 and 3 of each cluster frame, the base station A can transmit an audio signal as indicated by the symbol V.

  As described above, according to the present embodiment, the synchronization signals of the base station A and the base station B do not interfere with each other. Therefore, even in a region where the communication area of the base station A and the communication area of the base station B overlap, the mobile station can communicate with the base station A or the base station B without interference. Therefore, the service area can be widened with one carrier frequency without reducing traffic.

  Next, a frame used for data transmission will be described with reference to FIG. When data is transmitted from the base station A to the mobile station in a state where voice transmission is not performed from the base station A and the base station B, the base station A transmits the synchronization signal of the base station A as shown in FIG. A transmission frame or frames 1 to 3 are used. Further, when data is transmitted from the base station B to the mobile station in a state where no voice is transmitted from the base station A and the base station B, the base station B, like the base station A, A transmission frame or frames 1 to 3 are used.

  Next, a frame used for data transmission at the time of voice transmission will be described (see FIG. 5). When data is transmitted from the base station A to the mobile station in a state where voice transmission is performed from the base station A, the synchronization signal transmission frame of the base station A or the frame 1 is used. Further, when data is transmitted from the base station B to the mobile station in a state where voice transmission is performed from the base station A, the synchronization signal transmission frame of the base station B or the frame 1 is used. That is, the transmission unit 22 of each base station transmits data in a frame in which none of the base stations transmits voice and a frame that becomes a synchronization signal transmission frame of the own base station.

  An example frame configuration will be described with reference to FIG. 5 (a) and 5 (b) have the same frame configuration as FIG. 2 or FIG. 5A and 5B show a state where voice transmission is performed from the base station A. FIG.

  FIG. 5A shows a frame in which the base station A can transmit data to the mobile station. For example, the base station A uses the frame 0 of the synchronization signal transmission frame of the base station A, such as the frame 0 of the cluster frame 0 and the frame 0 of the cluster frame 2, or the frame 1 of each cluster frame. Can transmit data to the mobile station (see symbol D in FIG. 5A).

  On the other hand, FIG. 5B shows a frame in which the base station B can transmit data to the mobile station. For example, the base station B uses the frame 0 of the synchronization signal transmission frame of the base station B, such as the frame 0 of the cluster frame 1 and the frame 0 of the cluster frame 3, or the frame 1 of each cluster frame. Can transmit data to the mobile station (see symbol D in FIG. 5B).

  As described with reference to FIGS. 5A and 5B, data transmission is also possible for each cluster frame between the base station and the mobile station. For this reason, for example, taxi position information, information indicating the status of a taxi such as renting, empty car, and forwarding (supersign) can be transmitted between the base station and the mobile station even during voice communication between the base station and the mobile station. Can be transmitted and received sequentially. In addition, data communication can be performed over a wide area using one carrier frequency.

As described above with reference to FIGS. 2 to 5, the transmission unit 22 uses the synchronization signal in some frames (for example, frame 0) among a plurality of frames (for example, four frames) included in the cluster frame. And a voice signal in which the amount of information is compressed is transmitted in some frames (for example, frames 2 and 3) that do not transmit a synchronization signal among a plurality of frames.
Moreover, the transmission part 22 transmits a data signal with the flame | frame (for example, flame | frame 1) in which any base station does not transmit a synchronizing signal and an audio | voice signal among several frames. Further, the transmission unit 22 is a frame in which the base station transmits a synchronization signal (for example, the transmission unit 22 of the base station A is the frame 0 of the cluster frame 0 or 2, and the transmission unit 22 of the base station B is the cluster frame 1 or 3 frame 0), the data signal is transmitted together with the synchronization signal.

In the above description, the transmission of the base station using the transmission unit 22 has been described. However, the reception of the base station using the reception unit 23 is the same. Here, the configuration of the receiving unit 23 will be described in detail. The reception unit 23 includes a reception offset value storage unit 231. As with the transmission offset value storage unit 221, the reception offset value storage unit 231 stores an offset value from a reference frame in advance so that transmission timing does not overlap among a plurality of base stations. Yes. The receiving unit 23 receives a transmission signal from the mobile station in a cluster frame based on the reception offset value read from the reception offset value storage unit 231.
In the same base station, the offset values stored in the transmission offset value storage unit 221 and the reception offset value storage unit 231 are the same. For this reason, the transmission offset value storage unit 221 and the reception offset value storage unit 231 may have the same configuration (storage unit).

In the above description of the embodiment, the case of the FDMA method using the SCPC method as the communication method has been described. However, the present invention is not limited to this. For example, as a communication method, a TDMA (Time Division Multiple Access) method may be used.
In the above description of the embodiment, as a correction method for matching the frame timing of each base station between a plurality of base stations, a method for correcting a GPS PPS signal as a reference signal has been described. However, the present invention is not limited to this. It is not a thing. For example, a method of correcting by receiving a reference signal using a network, a method of receiving a transmission signal of a reference base station, and the like may be used. That is, the start timing of the cluster frame may be synchronized among the plurality of base stations based on the reference signals received by the plurality of base stations in common.

  Next, details of the selection device 13 described with reference to FIG. 1 will be described. The selection device 13 includes a data signal selection device 14 and an audio signal selection device 15. Here, the audio signal selection device 15 is described as being configured integrally with the control device 11. In the following description, the base station 2 or the base station 3 will be referred to as a base station device. The control station 1 will be described as a control station device.

  The audio signal selection device 15 selects a first base station device that transmits a first audio signal from among a plurality of base station devices. Then, the audio signal selection device 15 sends an audio signal completion signal indicating that the selected first base station device has completed transmitting the first audio signal from the selected first base station device. In response to the reception, the second base station apparatus that transmits the second audio signal, that is, the next audio signal can be selected.

  For example, in the audio signal selection device 15, the user who manages the control station device manually operates the input unit or the selection unit, thereby transmitting the first audio signal from the plurality of base station devices. The first base station apparatus to be selected is selected. Further, the voice communication device 12-2 or the voice communication device 12-3 corresponding to the first base station device selected by the voice signal selection device 15 is selected, that is, the first voice communication device. And operation which inputs a user's voice as the 1st voice signal is performed with the microphone which this 1st voice communication apparatus has. The control station apparatus transmits the input first audio signal to the first base station apparatus selected by the audio signal selection apparatus 15. Then, the selected first base station apparatus transmits the first audio signal to the mobile station as described with reference to FIGS.

  Here, the audio signal selection device 15 is configured so that no other base station device can be selected during the period in which the selected first base station device transmits the first audio signal to the mobile station. ing. Alternatively, the audio signal selection device 15 selects the selected first base station device during the period in which the selected first base station device transmits the first audio signal to the mobile station. To keep going. Here, the period during which the first base station apparatus transmits the audio signal to the mobile station is the first base station apparatus in which the audio signal selection apparatus 15 transmits the audio signal from among the plurality of base station apparatuses. Corresponds to a period from when the audio signal selection device 15 receives the audio signal completion signal from the selected first base station device.

  Thereafter, the first base station apparatus selected by the audio signal selection apparatus 15 sends the audio signal completion signal to the control station apparatus via the data communication line 4 in response to the completion of transmission of the first audio signal. To send. The audio signal selection device 15 transmits the second audio signal, that is, the next audio signal in response to receiving the audio signal completion signal from the selected first base station device. Can be selected from a plurality of base station apparatuses. Alternatively, the voice signal selection device 15 cancels the selection of the selected first base station device in response to receiving the voice signal completion signal from the selected first base station device.

  Thereafter, in the voice signal selection device 15, the user who manages the control station device manually transmits the second voice signal again from the plurality of base station devices via the input unit or the selection unit. Two base station apparatuses are selected. The user inputs the user's voice as a second voice signal using the microphone of voice communication apparatus 12-2 or voice communication apparatus 12-3 corresponding to the selected second base station apparatus. In the digital wireless communication system, the input second audio signal is transmitted via the selected second base station apparatus, and the same operation as described above is repeated. Thereafter, the control station apparatus uses the third audio signal, the fourth audio signal,..., The nth audio signal (where n is an arbitrary natural number) in the same manner as the first audio signal and the second audio signal. Then, the data is transmitted via the base station device.

  Thereby, the digital wireless communication system according to the present embodiment has the following effects. In general, there is a delay time in communication between the control station 1 and the base station 2 or the base station 3. Therefore, for example, when the control station 1 completes transmission of the transmission signal via the base station 2 and then the control station 1 starts transmission of the transmission signal via the base station 3, the base station 2 There is a possibility that a period in which both base stations with the base station 3 are transmitting transmission signals may occur. In this case, the mobile station (for example, the mobile station E in FIG. 6) located in the area where the communication area with the base station 2 or the base station 3 overlaps is transmitted from both base stations 2 and 3. Since the transmission signal is received, there is a possibility that the transmission signal cannot be received normally.

  On the other hand, in the present embodiment, as described above, the audio signal selection device 15 transmits an audio signal completion signal indicating that the selected base station device has completed transmitting the audio signal. In response to reception from the selected base station apparatus, the base station apparatus that transmits the next audio signal can be selected. That is, in any period, only one of the plurality of base station apparatuses transmits a transmission signal that is an audio signal.

  Thus, even when there is a delay time in communication between the control station 1 and the base station 2 or the base station 3, for example, the control station 1 completes transmission of the transmission signal via the base station 2, and In addition, even when the control station 1 starts transmission of a transmission signal via the base station 3, there is no period during which both the base stations 2 and 3 transmit the transmission signal. . Therefore, a mobile station (for example, mobile station E in FIG. 6) located in an area where the communication areas with the base station 2 or the base station 3 overlap each other receives transmission signals from both the base station 2 and the base station 3. Since only the transmission signal from any one base station is received, this transmission signal can be received normally.

  Similarly to the audio signal selection device 15, the data signal selection device 14 selects a third base station device that transmits the first data signal from a plurality of base station devices. Then, the data signal selection device 14, like the audio signal selection device 15, transmits a data signal completion signal indicating that the selected third base station device has completed transmitting the first data signal. In response to reception from the selected third base station apparatus, the fourth base station apparatus that transmits the second data signal, that is, the next data signal, can be selected.

  The data signal selection device 14 operates on the data signal in the same manner as the audio signal selection device 15 for the audio signal described above, and thus is the same as the audio signal selection device 15 for the audio signal. The following effects are exerted on the data signal. Note that the data signal transmitted from the control device 11 to the mobile station via the base station device includes, for example, position information indicating a position that is a destination for dispatching a taxi that is a mobile station. In the digital wireless communication system according to the present embodiment, as described with reference to FIGS. 1 to 5, it is possible to independently transmit a transmission signal and a data signal from a base station apparatus. Therefore, the data signal selection device 14 and the voice signal selection device 15 can independently select a base station device that transmits a data signal or a voice signal from a plurality of base station devices.

  In the embodiment described above, since the digital wireless communication system includes the selection device 13, even when there is a delay in communication between the control station device and the base station device, only one of the base station devices can perform audio. Transmit signals and data signals. Therefore, this digital wireless communication system enables the mobile station to normally receive voice signals and data signals even when there is a delay in communication between the control station device and the base station device, It becomes possible to transmit.

  Note that the base station apparatus outputs to the control station apparatus a line state notification signal indicating whether or not the base station apparatus is transmitting a voice signal and whether or not the voice signal is being received. is doing. For example, the transmission unit 22 or the reception unit 23 of the base station device transmits this line state notification signal to the control station device via the data communication unit 25. Further, the control device 11 detects the line state of each base station device based on the line state notification signal received from each base station device, and any base station device based on the detected line state. It is also possible to determine whether to output a data signal from which frame and at which frame timing to output the data signal.

  The control device 11 may specify a base station device that transmits a data signal, specify a frame for transmitting the data signal, and output the data signal to the base station device. The designation of the frame for transmitting the data signal may be input by operating the input device connected to the control device 11 by the user, for example. For example, it is assumed that an input device, a display device, and the like (none of which are shown) are connected to the control device 11 as peripheral devices. Here, the input device refers to an input device such as a keyboard and a mouse. The display device refers to a CRT (Cathode Ray Tube), a liquid crystal display device, or the like.

The control device 11 may be realized by dedicated hardware. The control device 11 includes a memory and a CPU (central processing unit), and realizes the function of the control device 11. This function may be realized by loading the program into a memory and executing it.
The embodiment of the present invention has been described in detail with reference to the drawings. However, the specific configuration is not limited to this embodiment, and includes design and the like within the scope not departing from the gist of the present invention.

It is a block diagram which shows the structure of the digital radio | wireless communications system by one Embodiment of this invention. It is a block diagram which shows the frame structure as an example in the case of transmitting a synchronizing signal. It is a block diagram which shows the frame structure as an example in the case of transmitting an audio | voice signal. It is a block diagram which shows the frame structure as an example in the case of transmitting a data signal, when not transmitting the audio | voice signal. It is a block diagram which shows the frame structure as an example in the case of transmitting a data signal in the case of transmitting the audio | voice signal. It is a schematic diagram which shows the area which can transmit / receive the base station. It is a time chart which shows the conventional transmission / reception method. It is a block diagram which shows the structure of the cluster frame in the case of FIG.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Control station 2, 3, A, B ... Base station, 4-2, 4-3 ... Data communication line, 5-2, 5-3 ... Voice communication line, 11 ... Control apparatus, 12-2, 12 -3 ... voice communication device, 13 ... selection device, 14 ... data signal selection device, 15 ... voice signal selection device, 21 ... synchronization unit, 22 ... transmission unit, 23 ... reception unit, 24 ... reference signal generation unit, 25 ... Data communication unit, 26 ... Voice communication unit, 27 ... Multiple signal lines, 201 ... GPS antenna, 202 ... Transmission antenna, 203 ... Reception antenna, 221 ... Transmission offset value storage unit, 231 ... Reception offset value storage unit

Claims (6)

A plurality of base station apparatuses that communicate with a plurality of mobile station apparatuses using a single carrier frequency; and a control station apparatus that controls the plurality of base station apparatuses, and each of the base station apparatuses transmits a synchronization signal Digital that synchronizes the frame timing of the cluster frame to be transmitted among the plurality of base station apparatuses, and transmits the synchronization signal in the cluster frames in the order assigned to the base station apparatus in advance in the synchronized cluster frames A control station apparatus used in a wireless communication system,
A selection device that selects any one of the plurality of base station devices and transmits a transmission signal via the selected base station device;
A control station apparatus characterized by comprising: The transmission signal includes an audio signal;
The selection device is
An audio signal selection device that selects a first base station device that transmits a first audio signal from the plurality of base station devices;
Have
The audio signal selection device comprises:
In response to receiving from the selected first base station device an audio signal completion signal indicating that the selected first base station device has completed transmission of the first audio signal. The second base station device that transmits the second audio signal can be selected from the base station devices.
The control station apparatus according to claim 1. The transmission signal includes a data signal;
The selection device is
A data signal selection device that selects a third base station device that transmits a first data signal from the plurality of base station devices;
Have
The data signal selection device comprises:
In response to receiving from the selected third base station device a data signal completion signal indicating that the selected third base station device has completed transmission of the first data signal. The fourth base station device that transmits the second data signal can be selected from the base station devices.
The control station apparatus according to claim 1 or 2, characterized by the above. The cluster frame has a plurality of predetermined frames;
Each of the plurality of base station apparatuses is
Transmitting the synchronization signal in a part of the plurality of frames;
Transmitting an audio signal in which the amount of information is compressed in a part of the plurality of frames not transmitting the synchronization signal;
Among the plurality of frames, any base station device transmits a data signal in a frame that does not transmit a synchronization signal and a voice signal, or a data signal together with the synchronization signal in a frame in which the base station device transmits a synchronization signal. Send,
The control station apparatus according to any one of claims 1 to 3, wherein A digital wireless communication system having a plurality of base station devices that communicate with a plurality of mobile station devices using a single carrier frequency, and a control station device that controls the plurality of base station devices,
Each of the plurality of base station devices is
A synchronization unit that synchronizes the frame timing of the cluster frame that transmits the synchronization signal among the plurality of base station devices;
In the cluster frame synchronized by the synchronization unit, a transmission unit that transmits a synchronization signal in a cluster frame for each order assigned to the base station device in advance,
Have
The control station device is
A selection device that selects any one of the plurality of base station devices and transmits a transmission signal via the selected base station device;
A digital wireless communication system characterized by comprising: A plurality of base station apparatuses that communicate with a plurality of mobile station apparatuses using a single carrier frequency; and a control station apparatus that controls the plurality of base station apparatuses, and each of the base station apparatuses transmits a synchronization signal Digital that synchronizes the frame timing of the cluster frame to be transmitted among the plurality of base station apparatuses, and transmits the synchronization signal in the cluster frames in the order assigned to the base station apparatus in advance in the synchronized cluster frames A control method used in a control station apparatus used in a wireless communication system,
A selection procedure for selecting any one of the plurality of base station devices and transmitting a transmission signal via the selected base station device;
A control method characterized by comprising:

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