JPS6331976B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a relay system in a time division multiplex multiple access communication system.

[Conventional technology]

FIG. 1 shows an example of a system configuration of a time division multiple access communication system. That is, one central station B and the slave stations S ₁ to _{S o} scattered outside the service zone of the central station B can communicate through relay stations R ₁ to _{R o} .

Next, the operation of a conventional example of this system will be explained.

FIG. 2 shows the configuration of a time-divided channel (hereinafter referred to as time slot TS). That is, central station B, relay stations R ₁ to R _o , slave station S ₁
The information signals used between ~S _o are transmitted using one of the time-divided time slots TS ₀ ~ _{TS o} . Also, from the central station B to the relay stations R ₁ to _{R o}
or to slave station S ₁ via this relay station R ₁ ~ _{R o}
A synchronization signal is sent to ~S _o from the first time slot TS ₀ in one frame, and relay stations R ₁ ~ _{R o} and slave stations S ₁ ~ _{S o} are all synchronized with this synchronization signal. It receives and sends signals. Then, central station B sends out the time slot TS _o in the downstream direction, and after a certain period of time sends out the same time slot in the upstream direction.
A time relationship is set to receive TS _o .

FIG. 3 is a diagram explaining the time relationship between each station. In other words, the time relationship is such that when central station B sends a signal in time slot TS ₁ to relay station R ₁ , it receives a signal in the same time slot TS ₁ from lower relay station R ₁ after time ty (0) has elapsed. It is becoming. Therefore, the relay station _R1 must send out a time slot TS so that the signal is received at the central station B at the correct time.

[Problem that the invention seeks to solve]

Conventionally, in this type of relay device, as shown in FIG. . The signal demodulated by the demodulator 12 is reproduced by the signal processing circuit 13, then modulated by the modulator 14, and sent from the antenna 16 via the transmitter 15 to a lower-order relay station or slave station. On the other hand, the information signal from the lower station is
It is received by the antenna 20, passed through the receiver 21, demodulated by the demodulator 22, further regenerated by the signal processing circuit 23, modulated by the demodulator 24, and transmitted to the transmitter 2.
5 from the antenna 26 to a higher-order relay station or central station.

Now, the time relationship of the system including this relay station will be explained, assuming that the delay time of the signals at the transmitters 15, 25 and the receivers 11, 21 is not considered.

In Fig. 3, the signal sent from the central station B reaches the relay station R ₁ after the propagation delay time T _L due to the distance has elapsed.
The received signal is received by the signal processing circuit 13 in FIG. 4, and after a delay of time td required for regenerative relay occurs, it is sent to the lower station. Similarly, the signal from the lower station is delayed by the time td in the signal processing circuit 23, and then sent to the central station B after the propagation delay time _tL due to distance has elapsed.
reach. In this case, the propagation time t _L and the signal processing time td are constant, and the transmission time and reception time at the relay station cannot be adjusted. Therefore, in order for relay station _R1 , which has received the signal from the lower station, to send the signal accurately at the signal reception time of central station B,
A timing signal indicating the position of each time slot for recognizing and processing a signal received from a lower station after time ty(1) has passed since the time adjustment circuit 31 in FIG. 4 sends the signal to the lower station. It is necessary to send the signal to the signal processing circuit 23 and perform a signal relay operation. That is, with this timing signal, the signal processing circuit 23 of the relay station R ₁ opens a window for recognizing the time slot TS ₁ that is received after time ty(1) has elapsed since the signal was sent to the lower station. Processes the signal of time slot TS ₁ to create a constant delay time td.
Later, time slot TS ₁ is sent to central station B.

Further, in FIG. 1, transmission and reception are performed at another relay station Rm with the same delay time as above. In addition, except that the slave station does not have the fixed delay time td shown in Fig. 3, the time slot signal is sent to the upper station after adjusting the time of the sending signal in consideration of the delay time t _L and td at the relay station mentioned above. It is possible to send .

In such a case, for example, central station B and relay station R ₁
If an obstacle is created in the radio wave propagation path between relay station R1 and the radio wave propagation time changes, then relay station _R1
must readjust the time ty(1) from sending the signal to the lower station to receiving the received signal from the lower station. As a result, relay stations or slave stations lower than relay station _R1 must similarly readjust the time ty for transmitting signals to the upper station. In this readjustment, the time to send the signal to the upper station is ty
When determining ty(n), a similar time ty(n
-1) must be determined based on the formula ty(n)=ty(n-1)-2t _L -2td, which has the drawback of complicating time adjustment.

The present invention provides that, in a relay station, the time from when a signal divided into time slots is sent to a lower station to when a signal of the same time slot is received from a lower station is the same when counted from one central station or from the central station. The time from receiving a signal from a higher station to transmitting it to a lower station, or from the time a signal received from a lower station to transmitting to a higher station, is determined so that it is all constant within the service range of the relay station in the ranking. The above disadvantages are solved by configuring the relay station or slave station to change the time, and the time adjustment performed when transmitting a signal to a higher-level station at a relay station or slave station is performed when the relay station or slave station's higher-level station transmits a signal to a higher-level station. It is an object of the present invention to provide a wireless relay system for a time division multiplex multiple access communication system that does not affect the time adjustment performed when transmitting signals with the wireless communication system.

[Means for solving problems]

In a time division multiplex multiple access communication system having one central station, multiple relay stations, and multiple slave stations, the present invention conventionally provides a method for transmitting signals between one relay station and the central station or a station higher than the relay station. This solves the problem that when the delay time is changed, the amount of change in time also affects relay stations or slave stations that are lower stations than the relay station.

In other words, zone numbers are assigned in order of order counting from the central station, and a fixed time is set for each wireless zone.In other words, one relay station transmits a signal from a higher-level station to a lower-level station, and then receives the same signal sent from a lower-level station. Adjustment of time for receiving and transmitting signals between adjacent stations by uniquely determining the time it takes to receive a time slot signal and making the maximum delay between adjacent stations constant regardless of the wireless zone. is made to relate only to the distance between adjacent stations.

The present invention is characterized by a time-division multiplexing system having one central station, a plurality of relay stations connected in cascade around the central station, and a plurality of slave stations scattered around the relay station. In the access communication system, the above-mentioned relay stations are counted in the order of their installation locations away from the above-mentioned central station, and the counted number is assigned as the relay station's wireless zone number, and the propagation time of radio waves corresponding to the maximum distance between adjacent relay stations. and the signal processing time within the station, regardless of the wireless zone number, and set a limit to the sum, and at one relay station for each wireless zone number,
From the time when a time-divided signal is sent to a lower-level relay station or slave station, to the time when a signal in the same time slot as that transmitted by the relay station to the lower-level station is received from the lower-level station or slave station of the relay station. In the same way, the relay station transmits the signal received from the upper station with a delay to the lower station. , adding a delay to the signal received from the lower station and sending it to the upper station.If we focus on one relay station, the signal is received from the higher station in the same time slot as when it is received by the lower station. The delay time from the time when the signal is sent out to the above-mentioned time slot, and the delay time from the time when the signal of the same time slot as above is received from the lower station to the time when the signal is sent to the higher-order station are determined in the respective sections. The transmission time shall be determined by subtracting the propagation time of radio waves between adjacent relay stations from the time taken by the relay station.

〔Example〕

Next, embodiments of the present invention will be described with reference to the drawings.

FIGS. 5 and 6 are diagrams for explaining the time relationship between the central station and relay stations according to the present invention.

In FIG. 5, _the time slot transmitted from the central station B is received at the relay station _R1 after the radio wave propagation time tL has elapsed. Now, the time from when a signal of a certain time slot is sent to a lower station to when a signal of the same time slot is received from this lower station is fixed to a constant time. That is, in FIG. 6, the above times are expressed as time tz(1) at relay station R ₁ , time tz(2) at relay station R ₂ , and time tz(n) at relay station R _o . Fixed at a certain level. Therefore, when a relay station or a slave station that is a lower-level station sends a signal to a relay station or central station B that is a higher-level station than the relay station or slave station, the higher-level station transmits the signal. In order to ensure that the signal is accurately received by the upper station at the reception time slot determined by the fixed time from when the signal at the same time slot is received from the lower station,
The lower station sends a signal to the upper station. In this case, the time it takes for one central station to receive a signal from a higher-level station and send the signal to a lower-level station
tx, or the time tx from receiving a signal from a lower station to transmitting a signal to an upper station, is determined as follows. In other words, in FIG. 5, tx=1/2(tz(0)-2t _L -tz(1)). Furthermore, considering the maximum propagation distance in the service zone range and the time inevitably caused by the transmitter, receiver, modem, or signal processing in the relay station, the fixed time tz(0) of the central station B and the fixed time of the lower stations are determined. If the difference from the delay time tz(1) is determined as a _fixed time _t0 , then tx= _t0−2tL . This time relationship is shown in FIG. Therefore, the time tx from when a signal is received until it is sent out at one relay station can be determined as long as the propagation time of the radio wave with the upper station is known.

Next, a relay station device according to the present invention will be explained using FIGS. 7 and 8.

FIG. 7 is a block diagram of the relay station apparatus according to the embodiment of the present invention, and FIG. 8 is a detailed block diagram of the signal delay circuit 100 in FIG.

In FIG. 7, a signal sent from an upper station is received by an antenna 10, passed through a receiver 11, demodulated by a demodulator 12, delayed by a signal delay circuit 100, and then modulated by a modulator 14. Transmitter 1
5 to the lower station from the antenna 16.
On the other hand, a signal from a lower station is received by an antenna 20, passed through a receiver 21, and demodulated by a demodulator 22.
The signal is further delayed by the signal delay circuit 100, modulated by the modulator 24, and sent via the transmitter 25 from the antenna 26 to the upper station.

Signal delay circuit 100 is shown in FIG. now,
The signal of time slot TS ₁ is detected by start code detector 102 . The detection signal is input to the timing generation circuit 103, and the timing generation circuit 103 causes the storage circuit 1 to
A timing signal instructing the writing of the received signal to the memory circuit 101 is sent via the signal line a, and the data is stored in the memory circuit 101. Furthermore, the timing generation circuit 1
The timing signal from 03 is input to the timing generation circuit 105 after being delayed by the delay circuit 104, and a timing signal instructing the storage circuit 101 to read the signal is sent from the timing generation circuit 105 to the signal line b. Data is read from the memory circuit 101. The read signal is
Sent to lower station. Further, the timing signal from the timing generation circuit 105 is input to the timing generation circuit 112 after being delayed by a fixed delay circuit 106 for a time determined by the service zone. The timing generation circuit 112 sends a timing signal of a write command to the storage circuit 111 via the signal line c, and the storage circuit 111 stores the signal received from the lower station. Furthermore, the timing generation circuit 112
The timing signal from is delayed by the delay circuit 113 and then inputted via the signal line d to the timing generation circuit 114 for reading out the signal stored in the storage circuit 111. Data is read and sent to the upper station. At this time, the delay amount tx (tx=t ₀ −2t _L ) set in the delay circuits 104 and 113 is set by the delay amount setter 115.

As explained above, according to the present invention, by giving a delay amount specific to each relay station, a signal is sent from an upper station to a lower station between adjacent stations, and then the lower station further transmits a signal to a lower station. The time it takes to send out a signal, or the time from when a relay station receives a signal from a lower-level station to when that signal is received at a higher-level station of that relay station, is constant; The delay time when a station sends a signal to a higher-level station is determined simply by the propagation time of the radio wave depending on the distance to the higher-level station, which not only makes time adjustment easier, but also allows for easier time adjustment between one relay station and its higher-level station. Even if the signal transmission time at the relay station is readjusted because the delay time of the radio wave changes due to an obstacle or the like, there will be no effect on the relay stations or slave stations lower than the relay station.

In the above embodiment of the present invention, as shown in FIG. 6, after one relay station transmits a signal,
Although the time taken until the next lower station sends a signal is set constant, the present invention is not limited to this. In other words, as shown in FIG. 9, even if a relay station receives a signal from a higher-level station and transmits it to a lower-level station, even if the time is constant, the relay station receives a signal from a lower-level station and transmits a signal to a lower-level station. The time tx until sending to is expressed as tx=tz(0)−tz(1)−td−2t _L , and if we set tz(0)−tz(1)=t ₀ , then tx=t ₀ -td-2t _L , and is determined only by the propagation delay time depending on the distance between adjacent stations, so the same effect as in the previous embodiment can be obtained. Such an operation can be realized by keeping the delay circuit 104 constant in FIG. 8.

〔Effect of the invention〕

As explained above, by changing the delay time of the signal delay circuit provided in each relay station in accordance with fluctuations in the radio wave propagation time between stations, the present invention enables each relay station to reach the lower level at a predetermined correct time slot time. Can receive signals from stations. Therefore, even if the radio wave propagation time between stations fluctuates, each station can easily make time adjustments to correct this, and furthermore, lower stations are not affected by this time adjustment. As described above, according to the present invention, there is an effect that the time relationship of the time division multiple access method is stabilized.

[Brief explanation of the drawing]

FIG. 1 is a block diagram illustrating a time-division multiple access system. FIG. 2 is a diagram explaining time-divided time slots. FIG. 3 is a diagram explaining signal delay time. FIG. 4 is a block diagram of a conventional relay station device. FIGS. 5 and 6 are diagrams illustrating signal delay times. FIG. 7 is a block diagram of a relay station device according to an embodiment of the present invention. FIG. 8 is a block diagram of the signal delay circuit portion shown in FIG. 7. FIG. 9 is a diagram illustrating signal delay time. 10, 16, 20, 26... aerial, 11, 2
1... Receiver, 12, 22... Demodulator, 13, 2
3... Signal processing circuit, 14, 24... Modulator, 1
5, 25...Transmitter, 31...Time adjustment circuit, 1
00... Signal delay circuit, 101, 111... Memory circuit, 102... Start code detector, 10
3, 105, 112, 114... timing generation circuit, 104, 106, 113... delay circuit.

Claims (1)

[Claims] 1. Time division multiplexing multi-access system comprising a central station, a plurality of relay stations that relay communications from the central station in cascade, and a plurality of slave stations scattered around these relay stations. In the communication system, each of the relay stations described above is equipped with a delay means for delaying a communication signal, and the delay means is such that after an upper station transmits a signal in a certain time slot to its lower station, the lower station transmits a signal in the same time slot. The time it takes to receive a signal is determined by a time unique to each relay station, which becomes shorter in the order of communication relay from the central station, and each relay station responds to fluctuations in radio wave propagation time between it and its higher-level station. A radio relay system for a time division multiple access communication system, characterized in that the wireless relay system for a time division multiple access communication system is further provided with an adjusting means that adjusts the delay time of the delay means of the own station to always keep the unique time of the upper station constant.