JP2003199172A - Digital wireless relay system and wireless relay system - Google Patents

Abstract

(57) [Summary] In a digital wireless relay system including a control station, a relay station, and a mobile station, when the control station and the relay station are connected by a wireless line, the connection between the control station and the relay station is established by the wireless line. Takes a long time to perform signal processing, a difference occurs in the ease of line connection between the mobile station in the communication zone of the control station and the mobile station in the relay station zone. An object of the present invention is to eliminate the difference in ease of line connection. The control station includes a timing control unit that adjusts communication timing when communication is performed between a mobile station in a communication zone of the control station and a mobile station in a relay station zone. The difference between the line connection time with the mobile station in the station zone and the line connection time between the control station and the mobile station in the relay station zone is adjusted.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a digital wireless communication system, and more particularly to a digital wireless relay system having a relay station and a wireless relay system using the digital wireless relay system.

[0002]

2. Description of the Related Art Currently, a digital radio relay system which has been put into practical use has a plurality of mobile stations within a control station 51 and a communication area 52 (or also called a communication zone) of the control station 51, as shown in FIG. Communication connection service with the stations M1, M2, ... Or a communication area 54 of the relay station 53
A plurality of mobile stations m1, m2, ... Inside the control station 51
Alternatively, it is a system configured to provide a communication connection service with a plurality of mobile stations M1, M2, .... The base station 55 may be installed near the control station 51 or may be installed in a remote place. When installed at distant places, the control station 51 and the base station 55 are generally connected by a wire or a micro line. In the case of FIG. 6, the control station 51 and the base station 55 are installed in the same place. Control station 5
1 performs communication connection between a base station, a relay station and a plurality of mobile stations and maintenance and management of a service area in the digital wireless relay system. A line control device is installed in the control station 51, and control of calling from a mobile station or setting of a communication route is performed. In FIG. 6, the relay station 53
Is located within the communication area 52 of the control station 51,
It does not necessarily have to be located within the communication area 52. That is, when the control station 51 and the relay station 53 are connected by a micro multiplex line or a digital dedicated line, the relay station 53 does not need to be located in the communication area 52.

FIG. 7 shows radio carrier frequency allocation permitted for use in a narrow band digital radio system (including a digital radio relay system) including a local disaster prevention radio system using digital radio technology in Japan. . In FIG. 7, in the up direction, that is, mobile station → relay station →
In the direction of the control station, 4 MHz with 262 MHz as the reference
The z band has a width of 25 kHz and 160 waves (f1, f2, ...
・) Is recognized. In the downstream direction, that is, in the direction of control station → relay station → mobile station, 262 MHz in the upstream direction.
4MH based on 271MHz, which is 9MHz away from
The z band has a width of 25 kHz and 160 waves (F1, F2, ...
・) Is recognized. Therefore, in the communication of the digital wireless relay system, the upstream directions f1, f2, ...
Each frequency in the downlink directions F1, F2, ... Is used.
Then, each system can use one or a plurality of wireless carriers as control carriers and the rest as communication carriers according to the scale. Needless to say, such frequency allocation varies depending on regions and countries, but the standard for digital radio systems in Japan is ARIB (Association of Radio Industries and
Businesses) Standard-T79 (Published September 2001, Publisher
Association of Radio Industries and Businesses) (hereinafter abbreviated as ARIB STD)
Stipulated in.

In such a digital wireless relay system, when wireless communication is performed between mobile stations in different zones such as a control station zone and a relay station zone, the mobile station is in the relay station zone like an analog wireless communication system. Mobile station,
For example, the mobile station m1 is controlled by the control station 5 via the relay station 53.
A wireless communication is performed with a mobile station within the zone 1 such as mobile station M1. A wireless communication line controlled by the line control device of the control station is used for this wireless communication.

FIG. 4 shows the configuration of a conventional digital radio relay system. FIG. 4 shows the mobile station M in FIG.
The operation when 1 calls the mobile station m1 will be described. First, the operation will be described in the down direction, that is, in the direction of control station → relay station → mobile station. When a call (connection request) is issued from the mobile station M1, the control station 51 (or sometimes via the base station 55) detects the call and the control station 51 moves via the relay station 53. It is necessary to establish a call route with the station m1. First, the control station 5 sends a call from the mobile station M1.
1 is detected, the control station 51 determines that the line control device 401 and the line I / F (interface) 404 of the relay station 400.
And are connected via a transmission line 415 using a digital dedicated line or a micro multiplex wireless line.

The transmission signal TS propagating through the transmission line 415 is a frame-structured digital signal and is shown by the transmission signal TS in FIG. In FIG. 8, one frame is 40 msec, and the transmission signal TS is formed by repeating this frame. One frame is composed of 8 channels (CH1, CH2, ... CH8).
The channel length is 5 msec. And CH1 is
For example, it is a control channel, and CH2 to CH8 are used as communication channels, for example.

First, the line I / F 4 using the control channel
The signal received at 04 is applied to the data rearrangement unit 406 (hereinafter referred to as the data conversion unit 406). This data conversion unit 406 converts the transmission format in order to establish a wireless connection with a mobile station located in the relay station zone. That is, it operates in synchronization with the line control device 401 at the timing obtained from the timing generation unit 405, and is converted into a control channel signal in the wireless section under the control of the control unit 407. That is, as shown in FIG. 8, one frame,
The transmission signal TS of 8 channels is converted into two types of transmission signals C1 and C2 of 1 frame and 4 channels. here,
One frame of the transmission signals C1 and C2 is one frame of the transmission signal TS.
Although the length is 40 msec which is the same as the frame, the length of each channel of the transmission signals C1 and C2 is 10 msec.
Is.

The control channel whose format has been converted by the data conversion unit 406 is erroneous according to a preamble, a synchronization word, a control signal and a standard by a coder / decoder circuit 414 (hereinafter, the coder / decoder circuit is abbreviated as a channel codec). A correction code or the like is added and coding (encoding) is performed. The encoded control channel signal is applied to the transmission modulator 411-1 and converted into a signal capable of digital wireless communication with the mobile station. In ARIB STD, this control channel is a radio channel composed of commonly used slots and is defined as a control channel.

On the other hand, the line I / F 4 using the communication channel
The signal received at 04 is applied to the data conversion unit 406 as in the case of the control channel described above. The signal of the communication channel applied to the data conversion unit 406 operates in synchronization with the line control device 401 at the timing obtained from the timing generation unit 405, and is transmitted under the control of the control unit 407 as shown in FIG. Only audio data is extracted from the signal TS, and CH2 to CH4 are transmitted to the transmission signal C1 and C
H5 to CH8 are converted into a transmission signal C2 and supplied to the channel codec 414. Channel codec 414
Then, a preamble, a synchronization word, an error correction code, and the like are added to the communication channels of the transmission signals C1 and C2 and coded to become a baseband signal in the wireless section. The transmission signals C1 and C2 are respectively transmitted to the transmission modulator 411-
1, 411-2. Transmission modulator 411-1,
The transmission signals C1 and C2 applied to 411-2 are converted into signals capable of digital wireless communication with a mobile station, amplified by power amplification units 410-1 and 410-2, and then transmitted via a transmission filter 409. Are supplied to the antenna 408. As a result, the transmission signals C1 and C2 are output from the antenna 408 at frequencies F1 and F2 as downlink communication waves, as described above. As a result, the antenna 408 of the relay station and the antenna 402 of the mobile station are connected by a digital wireless line. In the mobile station, the transmitter / receiver 40
3 makes it possible to receive the control channel signal and the communication channel signal from the relay station. Here, in ARIB STD, the communication channel is a radio channel composed of individual allocation slots, and this is defined as a communication channel.

The transmission modulators 411-1 and 411-2 are provided.
There are various digital modulation methods used in the above, and a predetermined modulation method suitable for a digital wireless communication system is used. For example, the π / 4 shift QPSK modulation method and the like are frequently used modulation methods.

Next, in the upstream direction, that is, mobile station → relay station →
The operation in the direction of the control station will be described. Transmitter / receiver 40
The signals of the above-mentioned frequencies f1 and f2 transmitted from the antenna 3 through the antenna 402 are received as reception information by the antenna 408 of the relay station, frequency-separated by the reception filter 413, band-limited, and then the reception demodulator. 415
-1 and 415-2. Reception demodulator 415
-1 and 415-2 demodulate the received information by a predetermined demodulation method, and further, the channel codec 414
Is output to. In the channel codec 414, decoding (decoding) including error correction according to the standard is performed (signal processing opposite to the downlink direction is performed), so that the reception information is the transmission signal C1 and the transmission signal C1 in FIG. C2 is obtained, and the control channel signal and the communication channel signal are obtained. The control channel signal and the communication channel signal are applied to the data conversion unit 406, and the conversion reverse to the above-mentioned downlink channel conversion is performed to obtain the transmission signal TS of FIG. The control unit 407 selects necessary data and then sends a selection signal from the line I / F 404 to the transmission line 4
It transmits to the line control apparatus 401 via 15, and a communication route is established.

[0012]

The conventional digital wireless relay system described above has the following problems. (1) When connecting the line control device of the control station and the relay station with a digital leased line, you will be renting a digital line of another company, and you will be charged a usage fee. It becomes big and becomes a problem. (2) When the line control device of the control station and the relay station are connected by a digital leased line, the digital leased line may be disconnected due to external factors such as a disaster. Especially, in the case of a disaster prevention digital wireless communication system. In addition, the unavailability of the system is a serious reliability drawback. (3) When the line control device of the control station and the relay station are connected by micro multiplex radio, the cost of the micro multiplex radio equipment is high, and the ratio of the cost of the micro multiplex radio equipment to the cost of the private radio communication system equipment However, there is a drawback that it is difficult for self-employed users to introduce because it requires a high degree of worker qualification to handle micro multiplex radio equipment.

The above-mentioned problems (1) to (3) can be solved by connecting the control station and the relay station by a wireless line. As a result, it is possible to provide a digital wireless system that is highly reliable and has low maintenance costs in the event of a disaster. However, if the control station and the relay station are connected by a wireless line, it takes time to process the signal for connecting to the relay station by the wireless line, as will be described later. A new problem arises in that there is a difference in ease of line connection between a mobile station and a mobile station within the relay station zone.

In view of the above, it is an object of the present invention to provide a digital wireless relay system that can easily connect to a line by making it possible to eliminate this problem.

[0015]

In order to achieve the above object, a digital radio relay system according to the present invention comprises a control station having a line controller and at least one first station existing in a communication zone of the control station. Mobile station, a relay station connected to the control station via a wireless line, and at least one second mobile station existing in the communication zone of the relay station, and the first and second mobile stations communicate with each other. In this case, the line controller is provided with a timing controller for adjusting the communication timing between the first and second mobile stations.

More specifically, the line control unit is provided with a storage unit for storing the communication area positions where the first and second mobile stations are located, and the first unit is based on the position information of the first mobile station from the storage unit.
The communication timing of the mobile station is delayed.

Further, the digital wireless relay system of the present invention has a base station, and the base station is located in the control station,
Since the communication zone of the base station and the communication zone of the control station are common, the line control unit controls communication between the base station and the relay station.

Further, in the digital wireless relay system of the present invention, the predetermined frequency band assigned to the communication between the control station and the first mobile station is the same as the predetermined frequency band assigned to the communication between the control station and the relay station. It is designed to be

Further, the control station of the digital wireless relay system of the present invention comprises a line control unit, a data conversion unit which is connected to the line control unit and converts the data of a transmission signal, and which is connected to the data conversion unit to determine a transmission signal. A first channel codec that is encoded / combined in the H.264 format and a first wireless transmission / reception unit that is coupled to the first channel codec and that transmits / receives a transmission signal to / from a first mobile station. It was done.

Further, the relay station of the digital radio relay system of the present invention comprises a second radio transmitter / receiver section for transmitting / receiving a transmission signal between the control section and the relay station, and a transmission signal connected to the second radio transmitter / receiver section. A second channel codec for encoding / decoding the data in a predetermined format, a channel conversion unit coupled with the second channel codec for channel conversion of the transmission signal, and a transmission signal coupled with the channel conversion unit for transmitting the transmission signal in a predetermined format. Comprising a third channel codec for encoding / decoding by the mobile station and a third radio transmitting / receiving unit which is coupled to the third channel codec and transmits / receives a transmission signal to / from a second mobile station. Is.

Further, the line control unit used in the control station of the digital radio relay system of the present invention is the position information of the mobile station located in the communication area of the control station and the mobile station located in the communication area of the relay station. It has a storage unit for storing the position information of the station, and the timing control unit adjusts the timing of communication between the first and second mobile stations based on the position information of the storage unit.

Further, in the digital wireless relay system of the present invention, the wireless relay system when the first and second mobile stations communicate with each other includes a step of detecting the positions of the first and second mobile stations,
The position of the first and second mobile stations is adjusted on the basis of the detection information to adjust the timing of communication between the first and second mobile stations.

Further, in the wireless relay system when the first and second mobile stations communicate with each other in the digital wireless relay system of the present invention, the line control device is provided in the communication area where the first and second mobile stations are located. By having a storage unit that stores the position and a timing control unit that adjusts the timing of communication between the first and second mobile stations, the step of adjusting the timing is the first step from the storage unit. The step is to delay the communication timing of the first mobile station based on the position information of the mobile station.

Further, in the wireless relay system when the first and second mobile stations communicate with each other in the digital wireless relay system of the present invention, the steps of detecting the positions of the first and second mobile stations are the first and the second. The second mobile station has a step of determining whether or not the line exists with the control station depending on whether or not the line is connected to the control station, and the step of adjusting the timing is such that the mobile station communicates with the control station. When existing in the area, the transmission timing of the control station is delayed by a predetermined time.

Furthermore, in the wireless relay system in which the first and second mobile stations communicate with each other in the digital wireless relay system of the present invention, the predetermined time is the first time when the control station is in the communication zone of the control station. The difference is between the line connection time with the mobile station and the line connection time with the control station via the relay station and the second mobile station located in the communication zone of the relay station.

[0026]

BEST MODE FOR CARRYING OUT THE INVENTION In a digital wireless relay system,
As described in FIG. 6, the service area 5 of the control station 51
2 (or it may be the communication area of the base station 55), communication between mobile stations, for example, between mobile stations M1 and M2, and installation of a relay station 53 at a high place such as a mountain peak. , Outside the service area 52 of the control station 51 and within the service area 54 of the relay station 53, for example, the mobile station m1 and the mobile station M in the service area 52 of the control station 51.
There is a case where 1 communicates with. In the latter case, control station 5
It is necessary to connect the transceiver device 1 and the transceiver device of the relay station. In such a case, since the number of channels of the relay station is generally plural, as described above, the relay station is generally connected by a digital leased line or a micro multiplex wireless line. However, if a digital leased line or a micro multiplex wireless line is adopted, the system may become unusable in the event of a disaster and the maintenance cost will increase. In order to solve this problem, the present invention adopts a method of connecting a transmitting / receiving device of a control station and a transmitting / receiving device of a relay station by a wireless line.
That is, by installing a transmitting / receiving device in the control station, a sufficient service is ensured for the mobile station within the communication area of the control station, and a wireless line is connected to the mobile station outside the communication area of the control station. It provides sufficient service via the relay station. Further, in the disaster prevention wireless communication system, users strongly request such a connection method using a wireless line. Although a new problem arises in that the mobile stations have different easiness of line connection due to the wireless line connection, the present invention is also a digital wireless relay system that solves this problem. .

A digital wireless relay system which is an embodiment of the present invention will be described below with reference to FIGS. 1, 2, 3, 5, 8 and 9. FIG. 1 is a block diagram showing the configuration of a digital wireless relay system that is an embodiment of the present invention. FIG. 2 is a time chart showing the operation of the digital wireless relay system of this embodiment. FIG. 3 shows a control station (control station 51 in FIG. 6) and a mobile station in the control station zone (mobile station M in FIG. 6) in the digital wireless relay system of this embodiment.
It is a block diagram which shows the structure of 1). FIG. 5 is a block diagram showing the configuration of the control station (control station 51 in FIG. 6) in the digital wireless relay system of this embodiment. 8 and 9 are diagrams showing frame configurations of transmission signals.

First, the configuration of the control station shown in FIG. 5 will be described. In FIG. 5, a line control unit 501 performs line connection control of a base station, a relay station, and a mobile station, such as call control and call route establishment control. In addition, this line control unit 501
Has a memory 504, always monitors in which communication area the mobile station is located, and stores the position of each mobile station in the memory 504. This monitoring method is, for example, an ID No. different for each mobile station. Is attached to this ID No. And the position information of the mobile station, it is determined whether the mobile station is located in the control station zone or the relay station zone and stored in the memory table 506 of the memory 504. Of course, this position information is updated appropriately. The transmission / reception unit 502 is used for transmission / reception with the mobile station and the relay station in the control station. The control unit 505 controls call origination from the mobile station, communication route setting, and the like. Command desk 50
Reference numeral 3 denotes an operator console of the digital wireless relay system according to the present embodiment, which has a function of selecting voice and non-voice and operating and managing the system.

Next, the operation between the control station and the mobile station in the control station zone will be described with reference to FIG. Reference numeral 300 is a control station, 301 is an antenna, and 302 is a transmitting / receiving unit of a mobile station located in the control station zone. 303 is a line control unit,
Reference numeral 304 is a line I / F (interface) of the control station. The line control unit 303 and the line I / F 304 are directly connected by wire, and communication is performed using a control channel and a plurality of communication channels. The transmitting / receiving unit 3 of the control station 300 and the mobile station
Since the transmission / reception operation between the relay station 400 and the mobile station 02 is the same as the transmission / reception operation between the relay station 400 and the transmission / reception unit 403 of the mobile station shown in FIG. 4, a brief description will be given here.

In FIG. 3, the operation in the down direction (control station → mobile station in control station zone) will be described first. A transmission signal TS (same as TS in FIG. 8) including a control channel and a communication channel sent from the line control unit 303 is applied to the data conversion unit 306 via the line I / F 304. Then, the signal received using the control channel of the transmission signal TS is applied to the data rearrangement unit 306 (hereinafter referred to as the data conversion unit 306). The data conversion unit 306 converts the transmission format in order to establish a wireless connection with a mobile station located in the control station zone.
That is, it operates in synchronization with the line control unit 303 at the timing obtained from the timing generation unit 305, and is converted into a control channel signal in the wireless section under the control of the control unit 307. That is, as shown in FIG. 8, it is converted into two types of transmission signals C1 and C2. Here, two types of transmission signals C1 and C
2 adopts a 4-multiplex TDMA (time division multiple access) system, and 4 slots form 1 frame. Details are specified in ARIB STD.

The control channel whose format has been converted by the data conversion unit 306 is a coder / decoder circuit 314 (hereinafter, the coder / decoder circuit is abbreviated as a channel codec) which complies with a preamble, a synchronization word, a control signal and a standard. An error correction code or the like is added, and coding (coding) is performed. The encoded control channel signal is applied to the transmission modulator 311-1 and converted into a signal that enables digital wireless communication with the mobile station.

On the other hand, the line I / F 3 is used by using the communication channel.
The signal received at 04 is applied to the data conversion unit 306. The signal of the communication channel applied to the data conversion unit 306 is based on the control of the control unit 307, as shown in FIG.
To 4 are converted into the transmission signal C1, and CH5 to CH8 are converted into the transmission signal C2, and are supplied to the channel codec 314. The channel codec 314 adds a preamble, a synchronization word, an error correction code, etc. to the communication channels of the transmission signals C1 and C2, encodes them, and
It is applied to the transmission modulators 311-1 and 311-2. Transmission signal C applied to the transmission modulators 311-1 and 311-2
1 and C2 are converted into signals capable of digital wireless communication with the mobile station, amplified by the power amplifiers 310-1 and 310-2, and then transmitted through the transmission filter 309 to the antenna 308.
Is supplied to. After being supplied to the antenna 308, the transmission signals C1 and C2 are output from the antenna 308 as downlink communication waves at frequencies F1 and F2. As a result, the antenna 308 of the control station and the antenna 3 of the mobile station
01 is connected by a digital wireless line. In the mobile station, the transmission / reception unit 302 can receive the control channel signal and the communication channel signal from the control station.

The transmission modulators 311-1 and 311-2 are provided.
There are various digital modulation methods used in the above, and a predetermined modulation method suitable for a digital wireless relay system is used. For example, the π / 4 shift QPSK modulation method and the like are frequently used modulation methods.

Next, in the upstream direction (mobile station in control station zone →
The operation of the control station will be described. The signals of the above-mentioned frequencies f1 and f2 transmitted from the transmission / reception unit 302 via the antenna 301 are received as reception information by the antenna 308 of the control station, frequency-separated by the reception filter 313, band-limited, and then received. It is output to the demodulation units 315-1 and 315-2. The reception demodulation units 315-1 and 315-2 demodulate the reception information by a predetermined demodulation method, and further output to the channel codec 314. In the channel codec 314, decoding (decoding) including error correction according to a standard or the like is performed,
Signal processing opposite to that in the downlink direction is performed, and the transmission signals C1 and C2 shown in FIG. 8 are obtained, and a control channel signal and a communication channel signal are obtained. The control channel signal and the communication channel signal are applied to the data conversion unit 306, and the conversion reverse to the above-mentioned downlink channel conversion is performed, and the transmission signal TS of FIG. 8 is obtained. The control unit 407
After selecting the necessary data from the transmission signal TS, the line I /
It is transmitted to the line control unit 303 from F304, and the communication route is established.

As described above, the control station 300 and the control station 30
Although the operation has been described for the mobile station in the communication area of 0, the timing when the control station 300 calls a mobile station in the communication area of the control station 300 will be described with reference to FIG. FIG. 2 is a schematic representation of the call timing between the control station, the relay station and the mobile station, and represents the same transmission signal as the transmission signal C1 or C2 shown in FIG. That is, the first frame, the second frame, ... Are repeated. Each frame has 4
Composed of channels. In addition, the channel is referred to as a slot here.

In FIG. 2, if the control station 300 calls a mobile station within the communication area of the control station using slot 1 of the downlink transmission signal DS1 (first slot of FLAME1), transmission / reception of the mobile station The section 302 indicates that the slot 302 of the uplink transmission signal US1 (the third slot of FLAME1) is used to respond to the control station 300. This is because the control station 300 of FIG.
This is because the signal processing such as data conversion is performed and the response is delayed by two slots, as is clear from the explanation of the operation. However, the mobile stations located in the communication area of the control station 300 all have the same conditions, and therefore there is no difference in the call timing between the mobile stations located in the communication area of the control station 300. Therefore, no trouble will occur in the line connection.

Next, the line connection of the mobile station located within the communication area of the relay station via the relay station will be described with reference to FIG. FIG. 1 shows a control station 300 (details are shown in FIG. 3).
From the relay station 100 to the relay station 100 using a wireless line, and further from the relay station 100 to the transceiver unit 105 of the mobile station within the communication area of the relay station 100. In FIG. 1, operation in the downlink direction (control station → relay station → relay station zone mobile station) will be described first. The signal transmitted by the antenna 308 of the control station 300 is
Similar to the communication between the control station 300 and a mobile station within the communication area of the control station 300 described with reference to FIG. 3, as downlink communication waves, the frequencies F1 and F2 are output from the antenna 308 and received by the antenna 106. To be done.

The transmission signals of the frequencies F1 and F2 are separated by the reception filter 107 and band-limited, and then output to the reception demodulators 111-1 and 111-2, respectively. Furthermore, the reception demodulation units 111-1 and 111-2 demodulate the reception information by a predetermined demodulation method, and the coder / decoder 1
13 (hereinafter, coder / decoder 113 is abbreviated as channel codec 113). The channel codec 113 performs error correction according to the standard and the like, decodes the received information, and obtains a control channel signal and a communication channel signal (becomes signals shown as transmission signals C1 and C2 in FIG. 8). The control channel signal and the communication channel signal are applied to the slot rearrangement unit 115 (hereinafter, simply referred to as the slot conversion unit 115).

The control channel signal and the communication channel signal applied to the slot conversion unit 115 are relay station 1 based on the synchronization timing of the timing generator 114 in the slot conversion unit 115 and the control of the control unit 116.
00 wireless channel control channel signals and communication channel signals. That is, as shown in FIG. 9, the two-system transmission signals C1 and C2 are converted into one-system transmission signal C3. As is apparent from FIG. 9, signals of 2 channels and 8 channels are appropriately selected and converted into signals of 1 channel and 4 channels. For example, when the channel CH1 of the transmission signal C1 is a control signal and the channels CH3, CH6, CH8 are communication channel signals, the transmission signal C3 includes channels CH1, CH3, CH6, CH8. The reason why the number of channels is small is that the control station needs to respond to calls from a large number of mobile stations or relay stations, so that eight channels are required. This is because only four mobile stations are targeted, so that four channels are sufficient.

Next, the transmission signal C3 generated by the slot converter 115 is applied to a coder / decoder 123 (hereinafter, the coder / decoder 123 is abbreviated as a channel codec 123). In the channel codec 123,
As in the case described above, the control channel signal and the communication channel signal are respectively added with a preamble, a synchronization word, a control signal, an error correction code according to the standard, etc.
Encoding is performed. The encoded transmission information is digitally modulated by the transmission modulator 119, and is output as a transmission signal of frequency F3 from the antenna 120 via the power amplifier 118 and the transmission filter 117. The transmission modulator 1
There are various digital modulation methods used in 19, and a predetermined modulation method suitable for a digital wireless communication system (including a digital wireless relay system) is used.
For example, the π / 4 shift QPSK modulation method and the like are frequently used modulation methods.

Antenna 120 of relay station 100 and relay station 1
It is connected to the antenna 104 of the mobile station in the 00 zone by a digital wireless line. In the mobile station within the communication area (relay zone) of the relay station 100, the transmission / reception unit 105 can receive the control channel signal and the communication channel signal from the control station.

Next, in the upstream direction (mobile station in relay station zone →
The operation of the relay station → control station) will be described. Relay station 10
Transmitter / receiver unit 1 of the mobile station in the communication area (relay station zone) of 0
The information signal transmitted from 05 as the transmission signal of frequency f3 from the antenna 104 is transmitted to the antenna 120 of the relay station 100.
After being received by and band-limited by the reception filter 122,
It is input to the reception demodulation unit 124. The reception demodulation unit 124 demodulates the input signal by a predetermined demodulation method. The demodulated information signal is output to the channel codec 123. In the channel codec 123, the information signal is subjected to error correction and the like according to the standard and the like, and is decoded to obtain a control channel signal and a communication channel signal. The control channel signal and the communication channel signal are applied to the slot conversion unit 115. The slot conversion unit 115 performs slot conversion reverse to the above-described downlink direction. That is, as shown in FIG. 9, the transmission signal C3 is converted into the transmission signals C1 and C2 and applied to the channel codec 113.

In the channel codec 113, the control channel signal and the communication channel signal are coded by adding a preamble, a synchronization word, a control signal and an error correction code in accordance with the standard, etc., and used as a baseband signal in the upstream radio section. , Transmission modulator 112-1
And 112-2. This baseband signal is digitally modulated by transmission modulators 112-1 and 112-2 and output to power amplifiers 110-1 and 110-2. There are various digital modulation methods used in the transmission modulator, and a predetermined modulation method suitable for a digital wireless communication system (including a digital wireless relay system) is used. For example, π / 4 shift QPSK The modulation method is a frequently used modulation method. The transmission signal that has been digitally modulated and amplified is band-limited by the transmission filter 109 to become transmission signals of frequencies f1 and f2, and output from the antenna 106. The transmission signals of the frequencies f1 and f2 are received by the antenna 308 of the control station 300, and the communication route is established.

The operation of the control station 300, the relay station 100 and the mobile station in the relay station area has been described above. In this case, however, the control station 300 calls a mobile station in the communication area of the relay station 100. The timing will be described based on FIG. As mentioned above, FIG.
Is a schematic representation of the call timing between the control station, the relay station, and the mobile station. In FIG. 2, the control station 300 uses the slot 1 of the downlink transmission signal DS1.
A case where a mobile station within the communication area of the relay station 100 is called by using (first slot of FLAME1) will be described. First, the control station 300 transmits the downlink transmission signal D
If the relay station 100 is called using the slot 1 of S1 (the first slot of FLAME1), the relay station 1
00 is a slot 33 (F of the downlink transmission signal DS2
The third slot of LAME1) is used for the relay, which is delayed by two slots. The reason for this delay is due to the delay due to the reception processing at the relay station, as described above.

Next, when the relay station 100 calls the mobile station within the communication area of the relay station 100 using the slot 33 of the transmission signal DS2, the mobile station within the communication area (relay station zone) of the relay station 100 is called. The transmission / reception unit 105 responds using the slot 41 (first slot of FLAME2) of the uplink transmission signal US3. That is, there is a delay of two slots. This is due to a delay for receiving processing inside the mobile station. Furthermore, the relay station 100
When the response of the mobile station in the communication area (relay station zone) is performed using the slot 41 of the upstream transmission signal US3, the relay station 100 causes the relay station 100 to receive the slot 27 of the upstream transmission signal US2 (FLAME2 The third slot) will be used to respond to the control station 300. That is, there is a delay of two slots. This delay is due to the reception processing in the relay station 100. As a result, the control station 30
The response time when a mobile station within the communication area of the relay station 100 is called from 0 via the relay station 100 is
This means that it is delayed by 4 slots, that is, by 1 frame, compared with the response time when a mobile station in the communication area of 0 is called.

As described above, when the control station 300 calls the mobile station in the communication zone of the control station 300 and the mobile station in the communication zone of the relay station 100 using the first slot in the downlink direction, the response signal is received. The timing is the third slot delayed by two slots in the mobile station in the communication zone of the control station 300, while it is the seventh slot delayed by six slots in the mobile station in the communication zone of the relay station 100. Therefore, the incoming timing of the response signal is delayed by 4 slots, that is, by 1 frame, when the mobile station in the relay station zone is called as compared with when the mobile station in the control station zone is called. This delay is 40 msec, which is a serious problem in connection with the line. Also, when a call is made, the call is uncomfortable.

In order to solve this problem, in the digital wireless relay system of this embodiment, as shown in FIG. 5, the line control section 501 of the control station 51 is provided with a memory table 506, for example. It stores in which communication zone each mobile station is located. A call is made from a mobile station within the communication area of the relay station 100, for example, the mobile station m1.
When calling a mobile station within the communication area of the control station 300, for example, the mobile station M1, the control unit 505 of the line control unit 501.
Can be realized by delaying the timing of calling the mobile station M1 by one frame. It should be noted that the method of delaying by one frame can be easily realized by delaying by 4 slots during data conversion, for example.

As a method for specifying the position of the mobile station, an ID number is given to each mobile station, and the control station controls the ID number of the mobile station in the control station zone and the ID of the mobile station in the relay station zone. The numbers may be stored in the memory table 506 of the memory 504, and the contents of the memory table may be updated every time the mobile station moves its position.

Further, in the digital wireless relay system of this embodiment, as described above, if the radio frequency is assigned, the frequency can be effectively used. That is, in the case of the digital wireless relay system of the present embodiment, two sets of frequencies, for example, frequencies in the up direction are f1 and f2, and frequencies in the down direction are F1 and F2. Then, f1 / F1 and f2 / F2 are set when communication is performed between the transmission / reception unit of the control station and the mobile station in the control station zone, and when communication is performed between the transmission / reception unit of the control station and the transmission / reception unit of the relay station. assign. Then, when communication is performed between the transmission / reception unit of the relay station and the transmission / reception unit of the mobile station in the relay station zone, the frequency f3 in the up direction is used and the frequency in the down direction is set to F3. Since the same frequency is assigned to the transmission / reception unit of the control station, the transmission / reception unit of the relay station to / from the control station, and the transmission / reception unit of the mobile station in the communication area of the control station, the frequency can be effectively used.

Further, in the digital radio relay system shown in FIG. 1, the frequencies (frequency within a predetermined band) assigned to the transmitting / receiving section of the relay station are (f1 / F1, f2 / F2) and f3 / F3, f1 / F1, f2 / F
2) and f3 / F3 need to be separated from each other as much as possible. Therefore, the transmission filter 109 in the relay station
And 117, and the attenuation characteristics of the reception filters 107 and 122 must be sufficiently ensured. In order to reduce the influence of the transmission frequency (f1, f2) of the relay station 100 on the reception frequency f3, and to reduce the influence of the transmission frequency F3 of the relay station 100 on the reception frequency (F1, F2), it is usually 1 MHz. It is desirable to separate from each other. In addition, it is necessary to secure sufficient vertical and horizontal distances between the antennas to secure the amount of coupling attenuation.

[0051]

As described above, according to the present invention,
Since it provides a digital wireless relay system in which the control station and the relay station are connected by a wireless line using a plurality of frequencies within a predetermined band, a digital dedicated line between the control station and the relay station as in the past is provided. Alternatively, the frequency can be effectively used as compared with the method using the micro multiplex line.

Further, compared to the system in which the control station and the relay station are connected by a digital leased line, there is less possibility of line disconnection due to a disaster, and a highly reliable digital wireless relay system can be realized.

Further, the running cost of the system can be remarkably reduced as compared with the method of connecting with the digital leased line or the micro multiplex wireless line.

Further, although the control station and the relay station are connected by a wireless line, even when the mobile station in the control station zone and the mobile station in the relay station zone are connected, the same timing is used. Since it is possible to respond, good connection control can be performed.

[Brief description of drawings]

FIG. 1 is a block diagram showing the configuration of a digital wireless relay system that is an embodiment of the present invention.

FIG. 2 is a time chart showing the operation of the digital wireless relay system that is an embodiment of the present invention.

FIG. 3 is a block diagram showing a configuration of a control station and a mobile station in a control station zone in the digital wireless relay system which is an embodiment of the present invention.

FIG. 4 is a block diagram showing the configuration of a conventional digital wireless relay system.

FIG. 5 is a block diagram showing a configuration of a control station of the digital wireless relay system that is an embodiment of the present invention.

FIG. 6 is a diagram showing a schematic configuration of a digital wireless relay system.

FIG. 7 is a diagram showing allocation of wireless carrier frequencies used in a digital wireless relay system.

FIG. 8 is a diagram showing a frame configuration of a transmission signal in the digital wireless relay system which is an embodiment of the present invention.

FIG. 9 is a diagram showing a frame structure of a transmission signal in the digital wireless relay system which is an embodiment of the present invention.

[Explanation of symbols]

100: relay station 104: antenna 105: transmission / reception unit 106: antenna 107: reception filter 109: transmission filter 110-1: power amplification unit 110-2: power amplification unit 111-1: reception demodulation unit 111-2: reception demodulation unit 112-1: Transmission Modulation Section 112-2: Transmission Modulation Section 113: Coder / Decoder 114: Timing Generator 115: Slot Conversion Section 116: Control Section 117: Transmission Filter 118: Power Amplification Section 119: Transmission Modulation Section 120: Antenna 122: reception filter 123: coder /
Decoder 124: reception demodulator DS1: downlink (control station → relay station or mobile station) transmission signal DS2: downlink (relay station → mobile station) transmission signal US1: uplink (mobile station → control station) Transmission signal US2: Upstream (relay station → control station) transmission signal US3: Upstream (mobile station → relay station) transmission signal 1 to 7: Downward direction (control station → relay station or mobile station) transmission signal Slot 11: Upstream (mobile station → control station) transmission signal slot 21 to 27: Uplink (relay station → control station) transmission signal slot 31 to 37: down direction (relay station → mobile station) Transmission signal slot 41: Upstream (mobile station → relay station) transmission signal slot 300: control station 301: antenna 302: transmission / reception unit 303: line control unit 304: line I / F (interface) 305: timing Generation unit 306: Data transfer unit 307: Control unit 308: Antenna 309: Transmission filter 310-1: Power amplification unit 310-2: Power amplification unit 311-1: Transmission modulation unit 311-2: Transmission modulation unit 313: Reception Filter 314: coder / decoder circuit 315-1: reception demodulation unit 315-2: reception demodulation unit 400: relay station 401: line control device 402: antenna 403: transmission / reception unit 404: line I / F (interface) 405: timing generation Part 406: Data replacement part 407: Control part 408: Antenna 409: Transmission filter 410-1: Power amplification part 410-2: Power amplification part 411-1: Transmission modulation part 411-2: Transmission modulation part 413: Reception filter 414: Coder / decoder circuit 415: Transmission path 415-1: Reception demodulation unit 415-2: Reception demodulation unit 501: Line control unit 502: Transmission / reception unit 503: Command console 504: Memory 505: Control unit 506: Memory table 51: Control station 52: Control station communication area 53: Relay station 54: Relay station communication area 55: Base station M1, M2: Mobile stations m1, m2 in the communication area of the control station: Mobile stations TS, C1, C2 in the communication area of the relay station: Transmission signals

Claims (14)

[Claims] 1. A control station having a line control unit, at least one first mobile station located in a communication zone of the control station, and a relay station connected to the control station by a wireless line, At least one second mobile station is located in the communication zone of the relay station, and the line control unit is provided between the first and second mobile stations when the first and second mobile stations communicate with each other. A digital wireless relay system having a timing control unit that adjusts the timing of the communication. 2. The digital wireless relay system according to claim 1, wherein the line control unit has a storage unit that stores a communication area position in which the first and second mobile stations are located. Relay system. 3. The digital radio relay system according to claim 2, wherein the timing control unit of the line control unit is based on position information of the first mobile station from the storage unit, and communication timing of the first mobile station. The digital wireless relay system characterized by delaying. 4. The digital wireless relay system according to claim 1, further comprising a base station, the base station being located in the control station, and the communication area of the base station and the communication area of the control station being common. A digital wireless relay system characterized in that 5. The digital wireless relay system according to claim 1, further comprising a base station, the first mobile station is located within a communication area of the base station, and the line controller is the base station and the relay. A digital wireless relay system characterized by controlling communication between stations. 6. The digital wireless relay system according to claim 1, wherein a predetermined frequency band assigned to communication between the control station and the first mobile station and a predetermined frequency band assigned to communication between the control station and the relay station. A digital wireless relay system having the same frequency band. 7. The digital radio relay system according to claim 1, wherein the control station includes the line control unit, a data conversion unit that is coupled to the line control unit and converts data of a transmission signal, and the data conversion unit. A first channel codec coupled with and encoding / decoding the transmission signal in a predetermined format;
A first radio transmitter / receiver coupled to a first channel codec and transmitting / receiving the transmission signal to / from a first mobile station, wherein the relay station is provided between the controller and the relay station. A second wireless transceiver for transmitting and receiving the transmission signal; a second channel codec coupled to the second wireless transceiver for encoding / decoding the transmission signal in a predetermined format; and a second channel codec And a channel conversion unit for converting the transmission signal into a channel, and encoding the transmission signal in a predetermined format in combination with the channel conversion unit.
A digital radio having a third channel codec for decoding, and a third radio transmitter / receiver unit coupled to the third channel codec for transmitting / receiving the transmission signal to / from a second mobile station. Relay system. 8. The digital wireless relay system according to claim 7, wherein the line control unit includes position information of a mobile station located within a communication area of the control unit and a mobile station located within a communication area of the relay station. Characterized in that the timing control unit adjusts the timing of communication between the first and second mobile stations based on the position information from the storage unit. Digital wireless relay system. 9. A control station, at least one first mobile station located in a communication zone of the control station, a relay station connected to the control station by a wireless line, and a communication zone of the relay station. In a control station of a digital wireless relay system in which at least one second mobile station is located, the control station includes a line control unit, and a data conversion unit coupled with the line control unit for converting data of a transmission signal. A first channel codec coupled to the data converter for encoding / decoding the transmission signal in a predetermined format; and a first channel codec coupled to the mobile station via a wireless line. A control station comprising: a wireless transmission / reception unit for transmitting / receiving the transmission signal. 10. The control station according to claim 9, wherein the line control unit stores a position information of a mobile station in a communication area, and communication between mobile stations based on the position information of the storage unit. And a timing control unit that adjusts the timing of the control station. 11. A control station having a line control unit, at least one first mobile station located in a communication zone of the control station, and a relay station connected to the control station by a wireless line, In a wireless relay system of a digital wireless relay system in which at least one second mobile station is located within the communication zone of the relay station, the first and second mobile stations are used when the first and second mobile stations communicate with each other. A step of detecting the position of the station, and a step of adjusting the timing of communication between the first and second mobile stations based on the detection information of the positions of the first and second mobile stations. Wireless relay system. 12. The wireless relay system according to claim 11, wherein the line control unit stores a communication area position where the first and second mobile stations are located, and first and second mobile stations. A timing control unit that adjusts the timing of communication between the first mobile station and the step of adjusting the timing delays the communication timing of the first mobile station based on the position information of the first mobile station from the storage unit. A wireless relay system characterized by being steps. 13. A control station having a line control device, at least one relay station, and at least one mobile station, wherein the mobile station is in a communication zone of the control station and in a communication zone of the relay station. In a wireless relay system of a moving digital wireless relay system, a step of determining whether the mobile station exists in a communication area of the control station when the mobile station makes a line connection with the control station; And a step of delaying the transmission timing of the control station by a predetermined time when it is determined that the control station exists within the communication area of the control station. 14. The wireless relay system according to claim 13, wherein the predetermined time is a line connection time of the control station to a first mobile station in a communication zone of the control station, and the control station performs the relay. A wireless relay system characterized by being equal to a difference with a line connection time with a second mobile station located in a communication zone of the relay station via the station.