JP2021057748A - Relay station and radio communication system - Google Patents

Abstract

To provide a relay station which can change over an active and a standby apparatus in an arbitrary timing without regard to a communication state.SOLUTION: In a radio communication system 1, a control unit 17 controls antenna changeover units 15, 16 to connect either relay station#1 11 or relay station#2 12 to a to-higher-level station antenna 13 and a to-lower-level station antenna 14 to operate as an active apparatus, whereas to operate the other as a standby apparatus. The active apparatus inputs a radio frame from the to-higher-level station antenna 13 in synchronization with a clock signal CLK, to transmit it from the to-lower-level station antenna 14, and whenever inputting front information, which is arranged in a former region than a synchronous word SW in the radio frame, and rear information which is arranged in a latter region than the synchronous word SW, outputs the above information to the standby apparatus. The control unit 17 changes over the relay stations connected to the antenna changeover units 15, 16 in a period while the synchronous word SW is input to the active apparatus.SELECTED DRAWING: Figure 1

Description

The present invention relates to a redundant relay station and a wireless communication system.

Conventionally, the relay station of the disaster prevention radio has a dual configuration equipped with a spare machine in case of failure of the current machine.
As a system having a redundant configuration, for example, a system has been proposed in which both the current machine and the spare machine are operated, and the output of the current machine and the output of the spare machine are switched on the output side (transmission side) ( For example, see Patent Document 1.).
Further, when operating both the current machine and the spare machine, if the received signal is divided into two and supplied to both the current machine and the spare machine, the received signal level is lowered. Therefore, a method has also been proposed in which a switching means is provided on the receiving side of the system to switch between the current machine and the spare machine.

Japanese Unexamined Patent Publication No. 2008-177804

However, when the received signal is input by switching between the current machine and the spare machine, there are the following problems. For example, when a worker manually switches from a working machine to a spare machine during maintenance, if the switching is performed while the working machine is communicating, the spare machine is required to establish the communication included in the received signal. Since the synchronization signal is not received, even if the reception signal is received after switching, synchronization cannot be achieved and the received data is lost. Therefore, the worker needs to check the communication status of the current machine and switch when the current machine is not communicating. That is, the worker needs to switch in consideration of the communication status of the current machine. For example, in the case of disaster prevention radio, the worker calls the city hall or the like to tell the source of the disaster prevention radio whether or not some disaster prevention radio information is currently being communicated or is planned to be communicated in the future. After confirming that the disaster prevention radio information has not been announced at present, or that there is no plan to announce it in the future, it is necessary to switch between the current machine and the spare machine. Then, it is necessary to perform this confirmation operation for each relay station to be maintained, and there is a problem that the work efficiency at the time of maintenance is poor.
Therefore, the present invention has been made by paying attention to the above-mentioned conventional unsolved problems, and it is possible to switch between the current machine and the spare machine at an arbitrary timing without considering the communication situation. It is an object of the present invention to provide a relay station and a wireless communication system.

In order to achieve the above object, according to one aspect of the present invention, a receiving antenna, a transmitting antenna, a first relay and a second relay, the first relay and the first relay. The same clock signal as the first relay and the second switch that connect one of the two relays to the receiving antenna and the transmitting antenna, respectively, is relayed to the first relay. It outputs to the machine and the second relay, controls the first switch and the second switch, and controls one of the first relay and the second relay. A wireless frame having a control unit that connects to the receiving antenna and the transmitting antenna to operate as a working machine and the other as a spare machine, and includes a predetermined synchronization word and communication information. A relay station that transmits and receives by the receiving antenna and the transmitting antenna, and the control unit is the first switching device during the synchronization word period in which the synchronization word in the radio frame is transmitted. And a relay station characterized by switching by the second switch is provided.
Further, according to another aspect of the present invention, a wireless communication system including a higher-level station, a subordinate station, and a relay station of the above-described aspect in which information transmitted from the higher-level station is relayed to the subordinate station for transmission. Is provided.

According to one aspect of the present invention, it is possible to switch between the current machine and the spare machine at an arbitrary timing without considering the communication status, and it is possible to suppress a decrease in work efficiency during maintenance.

It is a schematic block diagram which shows an example of the wireless communication system which concerns on one Embodiment of this invention. It is a functional block diagram which shows an example of a receiving device. It is a functional block diagram which shows an example of a transmission device. It is a flowchart which shows an example of the processing procedure of a control part. This is an example of a synchronous burst frame configuration. This is an example of the frame configuration of the communication channel. It is a timing chart for explaining a signal flow.

The following detailed description describes many specific specific configurations to provide a complete understanding of embodiments of the present invention. However, it is clear that other embodiments can be implemented without being limited to such specific specific configurations. In addition, the following embodiments do not limit the invention according to the claims, but include all combinations of characteristic configurations described in the embodiments.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings. In the description of the drawings below, the same parts are designated by the same reference numerals. However, the drawings are schematic.
FIG. 1 is a configuration diagram showing an example of a wireless communication system 1 including a relay station having a redundant configuration according to an embodiment of the present invention, and is, for example, a disaster prevention wireless system. Here, the wireless communication system 1 will be described as conforming to the standard "ARIB STD-T115" of the municipal digital broadcast communication system, but the present invention is not limited to this, and is applied to other systems and other standards. May be good.
The wireless communication system 1 includes a higher-level station 2, a relay station 3, and a subordinate station 4, and the relay station 3 relays communication information from the higher-level station 2 to the subordinate station 4 and transmits the communication information to the subordinate station 4. ..

The relay station 3 has relay station No. 1 (first relay station) 11 and relay station No. 2 (second relay station) 12, one of which operates as a working machine and the other of which operates as a spare machine, and a higher-level station 2. High-level station antenna (reception antenna) 13 for wireless communication with, relay station antenna (transmission antenna) 14 for wireless communication with subordinate station 4, and relay station No. 1 11 Alternatively, an antenna switch (first switch) 15 of the relay station No. 2 12 that connects the relay station operating as the current machine and the relay station 13 of the higher-level station and disconnects the other relay station from the antenna 13 of the higher-level station. Control to control the relay station 3 and the antenna switch (second switch) 16 that connects the relay station operating as an active machine and the subordinate station antenna 14 and disconnects the other relay station from the subordinate station antenna 14. A unit 17 is provided.

The antenna switch 15 has a movable contact c, a fixed contact a, and a fixed contact b. The movable contact c is connected to the antenna 13 of the upper station, the fixed contact a is connected to the relay station No. 111, and the fixed contact is connected. b is connected to relay station No. 2-12. Similarly, the antenna switch 16 has a movable contact c, a fixed contact a, and a fixed contact b, the movable contact c is connected to the antenna of the subordinate station 14, and the fixed contact a is connected to the relay station No. 111. , The fixed contact b is connected to the relay station No. 2 12. The antenna switch 15 and the antenna switch 16 are controlled by the control unit 17, and by switching the antenna switch 15 and the antenna switch 16, the relay station No. 1 11 and the relay station No. 2 12 are superior to each other. The station antenna 13 and the subordinate station antenna 14 are selectively connected. The switching time of the antenna switch 15 and the antenna switch 16 is set to be shorter than the reception time of the synchronization word SW described later. For example, in the case of the wireless frames shown in FIGS. 5 and 6 described later, the period of the synchronization word SW is (96 bits / 900 bits) × 80 ms = 8.54 ms. As the antenna switches 15 and 16, for example, a high frequency relay having a switching time of 5 ms or less is applied.

The relay station No. 1 11 includes a receiving device 21 and a transmitting device 22. The receiving device 21 is connected to the fixed contact a of the antenna switch 15 and the transmitting device 22 is connected to the fixed contact a of the antenna switch 16. Similarly, the relay station No. 2 12 includes a receiving device 31 and a transmitting device 32, the receiving device 31 is connected to the fixed contact b of the antenna switching device 15, and the transmitting device 32 is a fixed contact b of the antenna switching device 16. Connected to.
The relay station No. 1 11 and the relay station No. 2 12 receive the same clock signal CLK from the control unit 17, and operate in synchronization with the clock signal CLK. Further, in the receiving devices 21 and 31 and the transmitting devices 22 and 32, a working spare signal instructing whether to operate as a working machine or a spare machine is input from the control unit 17, and the receiving devices 21 and 31 are used according to the input working spare signal. Operates as a machine or a spare machine.

When the relay station No. 1 11 operates as a working machine, the receiving device 21 receives the transmission data from the host station 2 via the antenna switch 15 and demodulates and decodes the receiving data to acquire the received data, which will be described later. Acquire the timing signal. Further, the acquired received data and timing signal are output to the transmitting device 22, the demodulated data and the timing signal are output to the receiving device 31 of the relay station No. 2 12 operating as a spare machine, and the timing signal is further output to the control unit. Output to 17.

Further, when the relay station No. 1 11 operates as a spare machine, the receiving device 21 receives demodulated data and a timing signal from the receiving device 31 of the relay station No. 2 12 operating as a working machine, and decodes the demodulated data. The received data is acquired, and the received data and the timing signal are output to the transmission device 22.
On the other hand, when the relay station No. 1 11 operates as a working machine, the transmission device 22 encodes the reception data input from the reception device 21, modulates the encoded reception data, and then transmits the coded reception data to the subordinate station 4. The transmitting device 22 transmits the received data to the subordinate station 4 at a timing synchronized with the timing at which the receiving device 21 receives the wireless frame from the timing signal and the clock signal input from the receiving device 21.

Further, when the relay station No. 1 11 operates as a spare device, the transmitting device 22 receives the received data and the timing signal from the receiving device 21 operating as the spare device, encodes and modulates the received data, and converts the modulated data. Generate and store in a predetermined storage area. In this way, even in the transmission device 22 when the relay station No. 1 11 operates as a spare machine, the sequential modulation data is generated and rewritten with the stored pre-modulation data, so that the relay station 2 of the current machine from the upper station 2 Preparations are made for transmitting the received data received by the receiving device 31 of No. 12 to the subordinate station 4.

The above description describes the operation of the receiving device 21 and the transmitting device 22 when the relay station No. 1 11 is a working machine or a spare machine, but the relay station No. 2 12 is a working machine or a spare machine. In this case, the receiving device 31 and the transmitting device 32 also perform the same operations as the receiving device 21 and the transmitting device 22.
The timing signal is a signal indicating the timing of starting reception of the synchronization word included in the reception signal described later. The control unit 17 switches the antenna by using the timing signal as a trigger. The receiving devices 21 and 31 detect the matching of the synchronization words, and output the timing signal from the detected timing to the period of the synchronization word.

FIG. 2 is a block diagram showing an example of the receiving device 21 and the receiving device 31.
Since the receiving device 21 and the receiving device 31 have the same function and configuration, the receiving device 21 will be described here.
The receiving device 21 includes a wireless receiving unit 41, an A / D conversion unit 42, a demodulation unit 43, a synchronization detection unit 44, and a decoding unit 45.
The reception signal consisting of the RF (Radio Frequency) signal from the upper station antenna 13 input via the antenna switch 15 is input to the radio reception unit 41 and becomes an intermediate frequency signal (IF signal) or a base band signal. The converted and converted received signal is converted into a digital signal by the A / D conversion unit 42. After that, demodulation is performed by the demodulation unit 43, and demodulation data is generated.

In the case of a relay station instructed to operate as a working machine by a working backup signal described later input from the control unit 17, the synchronization detection unit 44 outputs a timing signal from the demodulated data generated by the demodulating unit 43. The generation unit 45 decodes the demodulated data and acquires the received data. On the other hand, in the case of a relay station instructed to operate as a spare machine by a working spare signal, the synchronization detection unit 44 outputs a timing signal input from a receiving device 31 operating as a working machine to a transmitting device 32. Then, the decoding unit 45 decodes the demodulated data input from the receiving device 31 operating as the current machine and acquires the received data.

FIG. 3 is a block diagram showing an example of the transmitting devices 22 and 32.
Since the transmission devices 22 and 32 have the same function and configuration, the transmission device 22 will be described here.
The transmission device 22 includes a coding unit 51, a modulation unit 52, a D / A conversion unit 53, a wireless transmission unit 54, and a timing control unit 55.
The received data output from the receiving device 21 is modulated by the modulation unit 52 and stored in the storage unit 52a after being encoded and given a synchronization word by the coding unit 51.

In the case of a relay station instructed to operate as a working machine by a working backup signal input from the control unit 17, the D / A conversion unit 53 converts the modulated received data into an analog signal and performs timing. It is output to the wireless transmission unit 54 at the timing specified by the D / A output timing input from the control unit 55, and the wireless transmission unit 54 converts the received data converted into an analog signal into a transmission signal (RF signal). And send. On the other hand, in the case of a relay station instructed to operate as a spare machine by a working spare signal, the D / A conversion unit 53 does not perform analog conversion processing, and the wireless transmission unit 54 does not transmit received data. .. Further, the timing control unit 55 determines the transmission timing of the transmission signal transmitted from the wireless transmission unit 54 and the reception signal from the upper station 2 of the relay station operating as the current machine, based on the timing signal input from the reception device 21. The D / A output timing is adjusted so that it matches the reception timing of. That is, the D / A conversion unit so that the transmission start timing of the wireless frame transmitted by the transmitting device 22 to the subordinate station 4 and the reception start timing of the wireless frame received by the receiving device 21 from the higher station 2 are the same. By controlling the output timing in 53, the communication information of the wireless frame when switching from the current machine to the spare machine is not lost.

Returning to FIG. 1, the control unit 17 has an operation display unit 17a for operating the relay station. The control unit 17 outputs the same clock signal CLK to the relay station No. 1 11 and the relay station No. 2 12, and the timing signal is input from the receiving device 21 (or the receiving device 31) operating as the current machine. Further, when a switching instruction of the relay station operating as the current machine is input from the operation display unit 17a among the relay station No. 1 11 and the relay station No. 2 12, the relay station operates as the current machine at this point based on the timing signal. While the synchronization word is being output to the receiving device 21 (or receiving device 31), the antenna switching device 15 and the antenna switching device 16 for switching from the relay station of the current machine to the relay station of the spare machine are switched. At the same time, the relay station No. 1 11 and the relay station No. 2 12 are output with a working spare signal instructing switching for the spare machine to operate as a working machine.

FIG. 4 is a flowchart showing an example of the processing procedure of the control unit 17.
When the relay station 3 is performing the relay operation, the control unit 17 outputs a common clock signal CLK to the relay station No. 1 11 and the relay station No. 2 12, and also receives the receiving device 21 (or receiving) that operates as an active machine. A timing signal is input from the device 31).
During the relay operation, the input waits until the switching instruction is input from the operation display unit 17a (step S1-N), and when the switching instruction is input (step S1-Y), the control unit 17 steps from step S1. It shifts to S2, and it is determined whether it is a period during which the current machine can be switched to the spare machine based on the timing signal input from the receiving device of the current machine. That is, it is determined whether or not the synchronization word is input to the receiving device of the current machine. Then, if it is a period during which the synchronization word is input to the receiving device of the current machine (step S2-Y), the process proceeds to step S3, and if it is not during the period during which the synchronization word is input (step S2-N), synchronization is performed. Waiting for a word to be entered. In step S3, the switching signal is output to the antenna switching device 15 and the antenna switching device 16 to switch the antenna, and the active preliminary switching signal is output to the relay station No. 1 11 and the relay station No. 2 12. The spare machine switches the relay station that operates as the current machine. As a result, the relay operation is continued.

Next, in the wireless communication system 1, the configuration of a wireless frame of communication data exchanged by communication between the host station 2, the relay station 3, and the subordinate station 4 will be described.
The wireless frame includes a frame for a synchronization burst (SB0: Synchronous Burst0) and a frame for a communication channel (SC: Service Channel). Synchronous bursts and communication channels have different frame formats from each other. The radio frame lengths of the synchronous burst and the communication channel are 80 ms each, and data transmission is performed in units of radio frames. The radio frame length is not limited to 80 ms.

The synchronization burst is transmitted in front of the communication channel during communication and includes a synchronization word and a control channel so that the relay station 3 can synchronize. The communication channel is a channel used by the user for communication, and includes a traffic channel and a high-speed incidental control channel.
FIG. 5 is a diagram showing a radio frame configuration of the synchronous burst 71. The synchronization burst 71 includes a synchronization word (SW: Synchronous Word) 71a, a control channel (CCH: Control Channel) 71b, a preamble (Pa) 71c, and a preamble (Pb) 71d, and the synchronization word 71a is wireless. The control channels are arranged in the central region of the frame, before and after the synchronization word 71a, and the preamble (Pa) 71c and the preamble (Pb) 71d are arranged at the front and rear ends of the radio frame.

The synchronization word 71a is a fixed code pattern for synchronizing. The relay station 3 and the subordinate station 4 hold the same reference pattern as the synchronization word 71a in the radio frame of the synchronization burst, and when this reference pattern and the received signal match, the synchronization word 71a is detected and the synchronization word 71a is detected. By synchronizing at the timing of 71a, the relay station 3 and the subordinate station 4 can acquire information such as the control channel 71b included in the synchronization burst 71, and can detect the subsequent radio frame.
The control channel 71b is a channel for transmitting various control information. For example, the control channel 71b transmits a notification start instruction or the like as a ringing signal.
The preamble (Pa) 71c and the preamble (Pb) 71d notify the transmission of the radio frame.

FIG. 6 is a diagram showing a radio frame configuration of the communication channel 72. The communication channel 72 includes a synchronization word (SW) 72a and a high-speed associated control channel (FACCH: Fast Associated Control Channel) or a traffic channel (TCH: Traffic Channel) 72b, and the synchronization word 72a is the center of the wireless frame. A high-speed accompanying control channel or a traffic channel 72b is arranged in front of and behind the synchronization word 72a.
The synchronization word 72a is a code pattern for synchronizing with the receiving device of the relay station 3 like the synchronization word 71a included in the synchronization burst 71, and is different from the code pattern of the synchronization word 71a.

The high-speed accompanying control channel is a channel for high-speed transfer of control information in order to shorten the interruption time when the transfer of communication information such as voice data is temporarily interrupted and the control information is transferred. For example, the high-speed accompanying control channel transmits a signal for designating a plurality of subordinate station identification numbers, an end signal, an idle signal, and the like when calling the subordinate station 4.
The traffic channel is a channel for transmitting communication information such as voice data.
In the wireless frame of the synchronous burst 71 and the communication channel 72, the information included in the wireless frame as the control channel 71b, the high-speed incidental control channel, the traffic channel 72b, or the like is the communication information.

Next, the operation at the time of switching the relay station 3 will be described with reference to FIG. 7.
In FIG. 7, from the state where the relay station No. 1 11 operates as the working machine and the relay station No. 2 12 operates as the spare machine, the relay station No. 1 11 is switched to the spare machine and the relay station No. 2 12 is used as the working machine. The signal flow when operating is shown.
In FIG. 7, the upper row shows the signal flow at the relay station No. 1 11 and the lower row shows the signal flow at the relay station No. 2 12.
The host station 2 transmits the communication channel 72 following the synchronization burst 71.
The radio frame transmitted from the higher station 2 is received by the antenna 13 of the relay station 3 to the higher station, and is input to the relay station 1 11 via the antenna switch 15. When the receiving device 21 of the relay station No. 1 11 receives the wireless frame, it detects the synchronization word SW and outputs a timing signal to the control unit 17 and the transmitting device 22. Further, the data included in the wireless frame is the front part (front part information) composed of the data arranged in the area before the synchronization word SW and the rear part consisting of the data arranged in the area after the synchronization word SW. It is demodulated separately from (rear information), and the demodulated data is output to the relay station No. 2 12 which is a spare machine at the timing of demodulation.

Further, when the demodulation of the front part and the rear part of the wireless frame is completed, the receiving device 21 decodes them and outputs the decoded reception data to the transmitting device 22. In the transmission device 22, after encoding and modulating the decoded received data, the data corresponding to the front part of the wireless frame, the fixed code pattern held as the reference pattern of the synchronization word SW, and the data corresponding to the rear part. A radio frame composed of the above is transmitted from the subordinate station antenna 14 via the antenna switch 16.
When the radio frame is input from the relay station No. 1 11 in the receiving device 31 of the relay station No. 2 12 which is a spare machine, the front data and the rear data are decoded with the synchronization word SW of the radio frame in between. The received data is acquired, and the transmitting device 32 encodes the received data and modulates the received data to acquire the modulated data.

By repeating this operation frame by frame, the transmission data from the upper station 2 is input to the relay station No. 1 11 in order, demodulated and modulated, and then transmitted to the substation 4 in the input order. It is demodulated and modulated by relay station No. 2-12.
Here, in the current machine, the received wireless frame is demodulated once, then modulated again and transmitted. Generally, when transmitting a digital signal, noise is generated in the communication path, so that it is difficult for the receiving side to receive the exact same signal as the transmitting side. Even if some errors occur in the data due to noise, the technique of correcting the information on the receiving side is an error correction code. In order to correct errors, make the data you want to send redundant. This redundancy makes it possible to recover erroneous data. Normally, it is essential for a relay station to perform error correction relay. The data transmitted from the higher station 2 can be corrected for an error occurring between the higher station 2 and the relay station 3 by duplicating the data when the data is received by the relay station 3. Then, when transmitting from the relay station 3 to the subordinate station 4, the subordinate station 4 can correct the error occurring between the relay station 3 and the subordinate station 4 by again encoding the error and transmitting.

Further, in the receiving device 31 of the relay station No. 2 12 as a spare machine, the demodulated data received and obtained by the relay station No. 1 11 as the working machine is input, the demodulated data is decoded, and the decoded received data is used. Modulation data is generated by encoding with the transmission device 32. Then, the relay station No. 1 11 decodes the demodulated data acquired by the receiving device 21 and encodes the decoded received data by the transmitting device 32 to generate modulation data. Therefore, the modulation data obtained by the relay station No. 2 12 is the same as the modulation data generated by the relay station No. 1 11. Therefore, if the relay station No. 1 11 can acquire the demodulated data, even if the relay station No. 2 12 is switched to the current machine, the communication data can be continuously transmitted to the subordinate station 4 under the control. The station 4 can receive communication data from the higher-level station 2 regardless of the switching between the current machine and the spare machine at the relay station 3.

FIG. 7 shows the timing of switching from the above-mentioned working machine to the spare machine. Radio frames are transmitted from the higher-level station 2 in the order of the synchronous burst SB0, the communication channel SC1, the communication channel SC2, the communication channel SC3, and the communication channel SC4 in FIG. 7, and are used for communication to the receiving device 21 of the relay station No. 111. When the user performs an operation instructing the switching of the current machine on the operation display unit 17a at the time t5 when the channel SC3 starts to be input, the control unit 17 performs the synchronization word SW based on the timing signal from the receiving device 21. Is determined whether or not it is the period during which the is being received (synchronous word period). Then, the control unit 17 switches the antenna switch 15 and the antenna switch 16 at the time t8 while receiving the synchronization word SW of the communication channel SC3, and switches the relay station No. 2 12 from the spare machine to the current machine. The backup signal is output to relay station No. 1 11 and relay station No. 2 12.

Here, at the time point t8, the synchronous burst SB0 has been transmitted to the subordinate station 4 by the relay station No. 111, but the transmission device 22 transmits the communication channel (corresponding to the wireless frame) SC1 to the subordinate station 4. During the process, the current machine will be switched to the spare machine. Therefore, in the transmission device 22, after the wireless transmission unit 54 transmits the front portion of the wireless frame of the communication channel SC1 to the subordinate station 4, switching is performed at the time point t8, and the communication channel is communicated to the subordinate station 4. The rear part of the radio frame of SC1 is not transmitted.

On the other hand, in the relay station No. 2-12, the demodulation data is received from the relay station No. 111 at the timing when the relay station No. 111 acquires the demodulation data of the front part and the rear part of the communication channel SC1, that is, the time point t1 Therefore, the demodulation data of the front part of the communication channel SC1 is received from the relay station No. 111, and the demodulation data of the rear part of the communication channel SC1 is received from the relay station No. 111 at the time point t2. Therefore, the relay station No. 2-12 receives the front part and the rear part of the radio frame of the communication channel SC1 from the relay station No. 111, and then decodes the front part and the rear part of the radio frame to decode the communication channel SC1. The received data of the above is acquired, the acquired received data is encoded, and the modulation data is acquired at the time point t4. Then, at the relay station No. 2-12, the synchronization word SW of the radio frame of the communication channel SC1 is switched from the spare machine to the current machine at the time when the synchronization word SW of the radio frame of the communication channel SC1 should be transmitted to the subordinate station 4, that is, at the timing of the time point t8. Of the modulation data acquired in, the data corresponding to the rear part of the radio frame of the communication channel SC1 is transmitted to the subordinate station 4 at the timing (time point t9) when the rear part of the frame of the communication channel SC1 should be transmitted. To do. At this time, in the relay station No. 2 12, the front part of the communication channel SC1 in the relay station No. 1 11 is based on the clock signal CLK and the timing signal common to the relay station No. 1 11 and the relay station No. 2 12. The data at the rear of the communication channel SC1 is transmitted to the substation 4 at a timing corresponding to the period corresponding to the synchronization word SW from the data transmission end timing of. At this time, the synchronization word SW in the wireless frame of the communication channel SC1 is not transmitted.

Therefore, in the wireless frame configuration of FIG. 6, the subordinate station 4 has a front portion of the communication channel SC1 transmitted from the relay station No. 1 11 and a rear portion of the communication channel SC1 transmitted from the relay station No. 2 12. Each is arranged as a high-speed accompanying control channel (FACCH) or a traffic channel (TCH) 72b, which is equivalent to transmitting a radio frame having a predetermined frame length (80 ms in this case). In this case, the subordinate station 4 is equivalent to receiving a radio frame that does not include the synchronization word SW as the radio frame of the communication channel SC1, but the subordinate station 4 once receives the synchronization word SW and synchronizes. When the processing is started as a state, the processing is continued as a synchronization state even if the normal synchronization word SW cannot be received during the predetermined protection period. Therefore, with the switching between the current machine and the spare machine, even if one wireless frame does not include the synchronization word SW, it can be determined that the synchronization state is achieved and the wireless frame can be continuously received.

Next, the communication channel SC2 is demodulated at the time point t6 at the relay station No. 111, the received data of the communication channel SC2 is decoded, and the received data is output to the transmission device 22. Then, at a time point t8 after the received data is output to the transmission device 22, the relay station No. 1 11 is switched from the current machine to the spare machine. The transmitting device 22 encodes and modulates the received data of the communication channel SC2 regardless of the current device and the spare device. However, since the transmitting device 22 is the spare device at the time point t8, the received data of the communication channel SC2 is encoded. Is not transmitted to the subordinate station 4.

On the other hand, the relay station No. 2 12 decodes the demodulated data of the communication channel SC2 input from the relay station No. 1 11 at the time point t3 and the time point t6 to obtain the received data, and then encodes and modulates the received data. Since the relay station No. 2 12 is switched to the current machine at the time t10 when the modulation data is acquired, the radio frame composed of the received data of the communication channel SC2 is transmitted from the relay station No. 2 12 to the subordinate station 4.
Next, in the communication channel SC3, since the antenna switch 15 and the antenna switch 16 are switched from the current machine to the spare machine at the time point t8, the front part of the communication channel SC3 is input to the relay station No. 1 11. , The rear part is input to the relay station No. 2-12.

The relay station No. 1 11 demodulates the front part of the communication channel SC3 and outputs the demodulated data to the relay station No. 2 12 at the time point t7, but the demodulated data is not processed thereafter.
Since the relay station No. 2-12 switches to the current machine at the time point t8, the reception of the radio frame from the higher station 2 is started, and the rear part of the communication channel SC3 is received at the time point t9.
Then, at the time point t11, the demodulated data obtained by demodulating the rear part of the communication channel SC3 is output to the relay station No. 111 which is a spare machine, and at the time point t7, the front part of the communication channel SC3 input from the relay station No. 111. The demodulated data of the above and the demodulated data (time point t11) obtained by demodulating the rear part of the communication channel SC3 input from the upper station antenna 13 via the antenna switch 15 are decoded to acquire the received data of the communication channel SC3. Then, this is encoded, modulated, and a radio frame of the communication channel SC3 is generated and transmitted to the subordinate station 4 (time point t12).

Next, the communication channel SC4 is received by the relay station No. 2 12 which is the current machine at this time, and the demodulation data of the front portion and the demodulation data of the rear portion are output to the relay station No. 1 11. Relay station No. 1 11 decodes the received data of the communication channel SC4 from the input demodulated data of the front and rear of the communication channel SC4, encodes it, and then modulates it, but does not transmit it to the subordinate station 4. ..
The relay station No. 2 12 decodes the received data of the communication channel SC4 from the demodulated data in the front portion and the demodulated data in the rear portion, encodes the data, modulates the data, and transmits the data to the subordinate station 4 (time point t13).

As described above, even when the current machine is switched from the relay station No. 1 11 to the relay station No. 2 12, the synchronous burst SB0 and the communication channels SC1 to SC4 transmitted from the upper station 2 are not missing. , Can be transmitted to the subordinate station 4.
In this way, the control unit 17 switches between the current machine and the spare machine when receiving the synchronization word SW regardless of the timing at which the switching instruction is input. Therefore, the upper station 2 The data of the traffic channel (TCH) 72b of the communication channel, which is the transmission data from the above, can be transmitted to the subordinate station 4 without being lost. Therefore, the user can switch between the current machine and the spare machine at an arbitrary timing without considering the data transmission timing of the higher-level station 2. As a result, for example, when switching between the current machine and the spare machine for maintenance or the like, the worker switches at any timing without considering the data transmission timing of the upper station 2 or the like. Can be done. Therefore, the work efficiency at the time of maintenance can be improved.

In the above embodiment, the case where the switching is performed at the timing when the operation display unit 17a gives the switching instruction and the next time when the synchronization word SW is received has been described, but the present invention is not limited to this. For example, if the interval between the timing at which the switching instruction is given on the operation display unit 17a and the timing at which the synchronization word SW is received next is short, the second synchronization word SW is displayed after the switching instruction is given. Switching may be performed at the timing of receiving, and if switching is performed during the period of the synchronization word SW, switching may be performed at the timing of receiving the synchronization word SW immediately after the switching instruction is given, and the switching instruction is given. After being broken, switching may be performed at the timing when two or more synchronization word SWs are received.

Further, in the above embodiment, the case where the switching instruction is given while receiving the communication channel SC3 has been described, but there is also the case where the switching instruction is given while receiving another communication channel. The operation is the same.
Further, when the switching instruction is given while receiving the synchronization burst SB0, the synchronization word SW has never been transmitted, so that the current machine and the spare machine cannot acquire the timing signal. Therefore, in this case, the switching may be performed after the timing signal can be received, that is, when the current machine and the spare machine can be synchronized with each other. According to the communication standard "ARIB STD-T115", the radio frame of the synchronous burst SB0 is transmitted multiple times. Therefore, if a switching instruction is given while receiving the synchronous burst SB0, the wireless frame is transmitted multiple times. After receiving the synchronization burst SB0, switching may be performed during the period of the synchronization word SW.

Further, in the above embodiment, the case where the worker switches between the current machine and the spare machine at the time of maintenance has been described, but it is not limited to the time of maintenance, and for example, in the current machine, it may affect the processing for the wireless frame. It can also be applied when switching the current machine when a minor abnormality occurs.
Further, in the above embodiment, the case where the synchronization word SW is located in the center of the wireless frame has been described, but the present invention is not limited to this, and the application is applied even when the synchronization word SW is located in the portion from the center of the wireless frame. It can be applied if the information of the wireless frame can be divided into a front part and a rear part with the synchronization word SW as a boundary.

Further, in the above embodiment, the case where the antenna switch 15 and the antenna switch 16 are switched at the timing when the start of reception of the synchronization word is detected when the timing signal is output has been described, but the present invention is not limited to this. Absent. If the switching between the antenna switch 15 and the antenna switch 16 is completed within the synchronization word period from the start of reception of the synchronization word to the end of reception, the switching may be performed at any timing within the synchronization word period.

Although the embodiment of the present invention has been described above, the above-described embodiment illustrates an apparatus or method for embodying the technical idea of the present invention, and the technical idea of the present invention is a component component. It does not specify the material, shape, structure, arrangement, etc. of The technical idea of the present invention may be modified in various ways within the technical scope specified by the claims stated in the claims.

1 Wireless communication system 2 Upper station 3 Relay station 4 Subordinate station 11 Relay station No. 1 (first relay)
12 Relay station No. 2 (second relay)
13 vs. upper station antenna 14 vs. subordinate station antenna 15 antenna switch (first switch)
16 Antenna switch (second switch)
17 Control unit 17a Operation display unit 21, 31 Reception device 22, 32 Transmission device 41 Wireless reception unit 42 A / D conversion unit 43 Demodulation unit 44 Synchroscope unit 45 Decoding unit 51 Code unit 52 Modulation unit 53 D / A conversion unit 54 Wireless transmitter 55 Timing control

Claims (6)

The antenna for reception and the antenna for transmission,
The first repeater and the second repeater,
A first switch and a second switch that connect any one of the first repeater and the second repeater to the receiving antenna and the transmitting antenna, respectively.
The same clock signal is output to the first repeater and the second repeater, and the first switch and the second switch are controlled to control the first repeater and the second repeater. A control unit that connects one of the repeaters to the receiving antenna and the transmitting antenna to operate as a working machine and the other as a spare machine.
Have,
A relay station that transmits and receives a wireless frame containing a predetermined synchronization word and communication information by the receiving antenna and the transmitting antenna.
The control unit is a relay station characterized in that switching is performed by the first switch and the second switch during the synchronization word period in which the synchronization word in the radio frame is transmitted. The first repeater and the second repeater each include a receiving device and a transmitting device.
When operating either one of the first repeater and the second repeater as the working machine,
The receiving device of the working machine receives the wireless frame from the receiving antenna in synchronization with the clock signal, and synchronizes the communication information included in the wireless frame with the timing of receiving the wireless frame. To output to the transmitting antenna via the transmitting device of the working machine, and
The relay station according to claim 1, wherein the receiving device of the working machine outputs the communication information included in the received wireless frame to the spare machine. In the wireless frame, the communication information is arranged in the regions before and after the synchronization word.
The receiving device of the working machine receives each time the front information in the area before the synchronization word and the rear information in the area after the synchronization word in the radio frame are input. The relay station according to claim 2, wherein the front information and the rear information are output to the spare machine. When operating any one of the first repeater and the second repeater as the spare machine,
The spare machine includes a storage unit that stores the communication information input from the receiving device of the working machine in association with the wireless frame containing the communication information.
When the control unit switches from the current machine to the spare machine, the other relay of the first relay and the second relay, which are newly used as the current machine, is switched. The rear information of the communication information included in the radio frame previously output to the transmission antenna is extracted from the storage unit, and the radio frame output to the transmission antenna before switching is performed. The relay station according to claim 3, wherein the extracted rear information is output to the transmission antenna at a timing when the synchronization word period is considered to have ended. When operating either one of the first repeater and the second repeater as the working machine,
The first relay or the second relay operated as the working machine detects the start timing of the synchronization word and outputs a timing signal, and the control unit outputs the timing signal based on the timing signal. The relay station according to any one of claims 1 to 4, wherein the machine is switched to a spare machine. It is characterized by including a higher-level station, a subordinate station, and the relay station according to any one of claims 1 to 5, which relays and transmits information transmitted from the higher-level station to the subordinate station. Wireless communication system.

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