JP2904261B2 - Digital wireless relay system - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a radio communication system, and more particularly, to a relay system used in microwave digital radio communication.

[0002]

2. Description of the Related Art Generally, a regenerative relay system is used in microwave digital radio communication, and a regenerative relay system shown in FIG. 2 is known as a regenerative relay system.

[0003] Referring to FIG. 2, the relay system shown includes a transmitting terminal station 11, relay stations 12 and 13, and a receiving terminal station 14.
Is sent to the receiving terminal station 14. For example, a control signal used for maintenance and inspection is superimposed on the main signal. The control signal is transmitted to the transmitting terminal station 11 and the relay station 12.
And 13 are superimposed on the main signal as necessary. In addition,
In the illustrated regenerative relay system, the transmitting terminal station 11, the relay stations 12 and 13, and the receiving terminal station 14 each have an active system and a standby system.

In the example shown in the figure, a transmitting terminal station 11 includes a supervisory control device (AS) 11a, and has an active modulator (MOD) 11b, a transmitter (T) 11c, and a standby modulator (MOD) 11d. And a transmitter (T) 11e. Modulators 11b and 11d each have an input terminal 1
11 and 112 are connected.

[0005] The relay station 12 includes a monitoring control device 12a,
Further, the working system receiver (R) 12b and the demodulator (DE)
M) 12c, a modulator 12d, a transmitter 12e and a standby receiver 12f, a demodulator 12g, a modulator 12h, and a transmitter 12i. Similarly, the relay station 13 includes a monitoring control device 13a, and further includes a working receiver 13b,
It includes a demodulator 13c, a modulator 13d, and a transmitter 13e, and a standby receiver 13f, a demodulator 13g, a modulator 13h, and a transmitter 13i.

[0006] The receiving terminal station 14 is provided with a supervisory control device 14a.
And a working receiver 14b and a demodulator 14b.
c, a standby receiver 14d and a demodulator 12e. Output terminals 141 and 142 are connected to the demodulators 14c and 14e, respectively.

Here, paying attention to the working system, a control signal including a transmission clock and control data is given from the monitoring control device 11a to the working system modulator 11b. The control data includes an ID indicating a relay station or a receiving terminal to which the control data is to be sent.
The code has been added.

An input terminal 111 is connected to an external device (not shown).
Is supplied with a main signal (baseband digital main signal). The modulator 11b superimposes a control signal on the main signal, that is, multiplexes the control signal to generate a modulated signal. Then, this modulated signal is transmitted as a transmission signal from the transmitter 11c.

In the relay station 12, a transmission signal from the transmission terminal station 12 is received by the receiver 12b as a reception signal, and given to the demodulator 12c. The demodulator 12c demodulates the received signal to obtain a demodulated signal, sends the main signal to the modulator 12d, and provides a control signal to the monitoring control device 12a. When the ID code in the control data indicates its own station, the monitoring control device 12a takes in the control data and sends a control signal to the modulator 12d. The modulator 12d superimposes (multiplexes) the control signal on the main signal and supplies the modulated signal to the transmitter 12e. The transmitter 12e sends out the modulated signal as a transmission signal.

[0010] The relay station 13 receives a transmission signal from the relay station 12. The relay station 13 operates similarly to the relay station 12, and the relay station 13 transmits a transmission signal from the transmitter 13e.

The transmission signal from the relay station 13 is received by the receiver 14b as a reception signal, and is provided to the demodulator 14c. The demodulator 14c demodulates the received signal, outputs a main signal from the output terminal 141, and provides a control signal to the monitoring control device 14a. When the ID code in the control data indicates its own station, the supervisory control device takes in the control data, but ignores the control data when the ID code is different.

[0012]

As described above, in the conventional wireless relay system, since a control signal is superimposed on a main signal for transmission, it is inevitable that each relay station reproduces the signal once. Therefore, non-regenerative relay cannot be used for transmission of the main signal. That is, when the non-regenerative relay method is used, there is a problem that the control signal cannot be superimposed on the main signal and transmitted.

An object of the present invention is to provide a digital radio relay system capable of transmitting a main signal by non-regenerative relay.

[0014]

According to the present invention, a transmitting terminal and a receiving terminal are connected via at least one relay station, and a main signal is transmitted between the transmitting terminal and the receiving terminal. In the digital wireless relay system adapted to transmit, the transmitting terminal station and the relay station generate control data as transmitting terminal station control data and relay control data, respectively. A first modulating data to generate a first modulated signal and transmitting it as a first transmission signal;
A second modulating means for modulating a transmission clock signal in synchronization with the first modulating means to generate a second modulated signal and transmitting the generated second modulated signal together with the main signal as a second transmitted signal; First transmitting means for operating the first modulating means at the time of transmitting the transmitting terminal control data, wherein the relay station receives the second transmitting signal and returns to the third transmitting signal again; A first receiving / transmitting means for transmitting the second transmission signal, a first reproducing means for receiving the second transmission signal and reproducing the transmission clock signal and the carrier signal, and the first reception means using the transmission clock signal and the carrier signal. A first demodulation means for demodulating the transmission signal of the first step to obtain the control signal, and a third modulation for generating a third modulation signal by modulating relay station control data using the transmission clock signal and the carrier signal Means,
A second control unit for operating the third modulation unit when transmitting the relay station control data; and receiving the first transmission signal and transmitting the same together with the third modulation signal as a fourth transmission signal. A second receiving / transmitting means, wherein the receiving terminal station has a second demodulating means for demodulating the main signal from the third transmitting signal, and a transmitting clock signal and a second transmitting signal from the third transmitting signal. Second reproducing means for reproducing the carrier signal; and third reproduction for reproducing the transmission terminal control data and the relay station control data from the fourth transmission signal using the transmission clock signal and the carrier signal. And a digital radio relay system characterized by comprising:

At this time, when the second control means receives the transmission terminal control data and the relay station control data from another relay station, the second control means stops the operation of the third modulation means.
Further, the transmission terminal station control data and the relay station control data each include an ID indicating a destination station to which the control data is to be sent.
When a D code is added, and each of the relay station and the receiving terminal station indicates that the ID code indicates its own station,
The control data is taken.

[0016]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the drawings.

Referring to FIG. 1, the digital radio relay system shown in FIG. 1 includes a transmitting terminal station 21, relay stations 22 and 23, and a receiving terminal station 24. The main signal is sent from the station 21 to the receiving terminal 24.

In the transmitting terminal station 21, a supervisory control device (AS)
21a sends out control data and a transmission clock. When sending the control data (DATA), the monitoring control device 21a controls the modulator (M) 21b to put the modulator 21b into an operating state. That is, the modulator 21b is connected to the monitoring control device 21.
and is turned on only when transmitting control data of the own station (transmission terminal station).

The modulator 21b is supplied with its own control data and a transmission clock signal from the monitoring control device 21a (here, the control data and the transmission clock signal are called AS transmission control signals). This AS transmission control signal is transmitted to the modulator 2
1b, and as a first modulated signal, a transmitter (T) 2
1c. On the other hand, the transmission clock signal is given to a pattern generator (PG) 21d,
d generates a pseudo random pattern according to the transmission clock signal. Then, the pseudo random pattern is provided to the modulator 21e. The modulator 21e is provided with a transmission clock signal, and the modulator 21e modulates a pseudo-random pattern according to the transmission clock signal and sends out a second modulation signal. Then, the second modulated signal is provided to the transmitter 21f. Note that a local oscillator signal is supplied from the modulator 21e to the modulator 21b, and the modulator 21b performs a modulation operation using the local oscillator signal.

The first main signal (data signal) is a modulator 21
g, where it is modulated and provided as a first main modulation signal to the transmitter 21f. On the other hand, the second main signal (empty signal) is supplied to the modulator 21h, where it is modulated and
Is given to the transmitter 21c.

The transmitter 21c combines the second main modulation signal and the first modulation signal and sends out the combined signal as a first transmission signal.
Similarly, the transmitter 21f combines the first main modulation signal and the second modulation signal and transmits the combined signal as a second transmission signal.

In the relay station 22, the receivers (R) 22a and 22b transmit the first and second transmission signals to the first
And a second received signal. The second received signal is branched by the hybrid circuit (H) 22c and provided to the demodulator (D) 22d and to the transmitter 22e. The transmitter 22e sends out the second reception signal again as a transmission signal (third transmission signal).

The demodulator 22d demodulates the second received signal and provides the resulting carrier signal and transmission clock signal to the demodulator 22f and the modulator 22g. Further, the demodulator 22d provides a transmission clock signal to the monitoring control device 22h.

The first received signal is provided to a transmitter 22i and to a demodulator 22f.

The demodulator 22f performs demodulation using the carrier signal and the clock signal, and supplies control data to the monitoring control device 22h. An ID code is added to this control data, and when the ID code indicates its own station, the monitoring control device 22h takes in the control data. On the other hand, if the ID code does not indicate the own station, the monitoring control device 22h ignores the control data.

Further, when receiving the control data, the supervisory control device 22h controls the modulator 22g to stop its operation. When transmitting the control data of itself (relay station), the supervisory control device 22h controls the modulator 22g to be in the operating state, but when the control data is transmitted from the transmission terminal station 21, the modulator 22g is activated. Will stop. Therefore, when the control data is not sent from the transmitting terminal station 21, the monitoring control device 22f gives its own control data to the modulator 22g, and the modulator 22g performs modulation using the carrier signal and the transmission clock signal, and performs the modulation. The signal (third modulated signal) is provided to the transmitter 22i. Then, the transmitter 22i combines the first received signal (in this case, control data is not included) and the above-described modulated signal and sends out the combined signal as a fourth transmission signal. If there is no third modulated signal, the transmitter 22i will transmit the first received signal as a fourth transmitted signal.

The relay station 23 has the same configuration as the relay station 22. The relay station 23 includes receivers 23a and 23b, a hybrid circuit 23c, a demodulator 23d, a transmitter 23e, a demodulator 23f, a modulator 23g, Device 23h, transmitter 2
2i.

The operation of the relay station 23 is the same as that of the relay station 22 and will not be described again. However, even in the relay station 23, when the supervisory control device 23h receives the control data, the operation of the modulator 22g is stopped. I do.

At the receiving terminal 24, the receivers 24a and 24b
Receiving the third and fourth transmission signals transmitted from the relay station 23 as third and fourth reception signals, respectively.

The fourth received signal is demodulators 24c and 24d
The demodulator 24c demodulates the fourth received signal to obtain a first main signal, and outputs the first main signal.
On the other hand, the demodulator 24d demodulates the first received signal, reproduces the transmission clock signal, and provides it to the monitoring control device 24e.

The third received signals are demodulators 24f and 24g.
The demodulator 24f demodulates the third received signal to obtain a second main signal (empty signal), and outputs the second main signal. On the other hand, the demodulator 24g demodulates the third received signal and provides control data to the monitoring control device 24e.

The monitoring control device 24e uses the I
When the D code represents the own station, the control data is taken in, and when the ID code is different, the control data is ignored.

As described above, the monitoring and control devices 21a, 22
Since h and 23h transmit control data in a time-division manner by polling, when the monitoring control device 21a transmits control data to any of the monitoring control devices 22h, 23h and 24e, monitoring control is performed. Devices 22h and 23
h controls the modulators 22g and 23g, respectively, to stop the operations of the modulators 22g and 23g.

Similarly, when the monitoring control device 22h transmits the control data (at this time, the monitoring control device 21a does not transmit the control data, that is, the monitoring control device 21a The operation of the modulator 21b is stopped), and the monitoring control device 23h controls the modulator 23g to stop the operation of the modulator 23g.

Further, a modulator 21e and demodulators 22d, 2d,
By 3d and 24c, the carrier signal and the transmission clock signal are kept in a synchronized state in each station, so that the synchronization is not lost even when the transmission timing is switched in each of the monitoring control devices 21a, 22h, and 23h.

[0036]

As described above, in the present invention, the carrier signal and the transmission clock signal are synchronized in each station, so that the main signal (first main signal) is transmitted by the non-regenerative relay system, and There is an effect that control data can be transmitted to each station in a time-division manner.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating an embodiment of a digital wireless relay system according to the present invention.

FIG. 2 is a block diagram for explaining a conventional digital wireless relay system.

[Explanation of symbols]

 21 transmitting terminal station 22, 23 relay station 24 receiving terminal station

Claims (3)

(57) [Claims] 1. A digital radio relay system in which a transmitting terminal and a receiving terminal are connected via at least one relay station and a main signal is transmitted between the transmitting terminal and the receiving terminal. , The transmitting terminal station and the relay station generate control data as transmitting terminal station control data and relay control data, respectively. The transmitting terminal station modulates the transmitting terminal station control data to generate a first modulated signal. And a first modulating means for generating a second transmission signal as a first transmission signal, and a second modulation signal generated by modulating a transmission clock signal in synchronization with the first modulation means to generate a second modulation signal together with the main signal. A second modulation means for transmitting the transmission terminal station control data, and a first control means for operating the first modulation means at the time of transmitting the transmission terminal station control data. And the third transmission signal is received again. First receiving and transmitting means for transmitting as a transmission signal, and the transmission clock for receiving the second transmission signal
First reproducing means for reproducing a signal and a carrier signal, and the first reproducing means using the transmission clock signal and the carrier signal.
A first demodulation means for demodulating the transmission signal of the first step to obtain the control signal, and a third modulation for generating a third modulation signal by modulating relay station control data using the transmission clock signal and the carrier signal Means, second control means for operating the third modulation means at the time of transmission of the relay station control data, and a fourth transmission signal together with the third modulation signal upon receiving the first transmission signal. A second receiving and transmitting means for transmitting the main signal from the third transmitting signal; and a transmitting means for transmitting the main signal from the third transmitting signal. A second reproducing means for reproducing a clock signal and the carrier signal; and a second reproducing means for reproducing the transmission terminal control data and the relay station control data from the fourth transmission signal using the transmission clock signal and the carrier signal. 3 of the playback means Digital radio relay system, characterized in that is provided. 2. The digital radio relay system according to claim 1, wherein the second control means receives the transmission terminal station control data and relay station control data from another relay station, and A digital radio relay system, wherein the operation of the third modulation means is stopped. 3. The digital wireless relay system according to claim 1, wherein an ID code indicating a destination station to which the control data is to be transmitted is added to each of the transmitting terminal control data and the relay station control data. And wherein each of the relay station and the receiving terminal station takes in the control data when the ID code indicates its own station.