JPH0744493B2 - 1 + 1 Frequency Diversity Radio Transmitter / Receiver for Fixed Communication - Google Patents

Description

TECHNICAL FIELD The present invention relates to a 1 + 1 frequency diversity radio transceiver in fixed communication, and more particularly to a 1 + 1 frequency diversity radio transceiver in fixed communication capable of stable transmission and reception with low power consumption. Regarding

[Prior Art] In the field of wireless communication, a 1 + 1 frequency diversity system in fixed communication is well known as a fading prevention measure.

This is a method that can always obtain a stable reception level by utilizing the fact that radio channels of different frequencies have a small correlation with fading. For this reason, the wireless transmission / reception device is widely used for fixed communication when forming a wireless relay line.

FIG. 2 is a block diagram of a conventional 1 + 1 frequency diversity radio transmitting / receiving apparatus in fixed communication.

In the figure, 101,111, are radio signal input terminals, 102,112
Is a wireless signal output terminal.

Further, 103, 104, 113, 114 are different frequencies f1
Transmitting circuits for a, f2a, f1b and f2b, and 105, 106, 115 and 116 are receiving circuits corresponding to these frequencies f1a, f2a, f1b and f2b.
And 107 and 117 are switching devices.

In the above configuration, the signal input from the wireless signal input terminal 101 is divided into two by the hybrid circuit, and the same signal is input to the two transmission circuits 103 and 104, respectively. Then, in each of the transmission circuits 103 and 104, it is converted into two radio frequencies f1a and f2a and sent out to the game.

In the receiving circuit 105, 106 of the game, two radio frequencies f1a, f2a
Are received separately. Then, of the two received signals, the normally received radio frequency signal is selected to always enable normal signal reception.

That is, the reception signal of the receiving circuit 105, which is the active system, is always selected as the wireless signal by the switch 107. Then, when the effect of frequency diversity occurs due to fading or the like, the receiving circuit 106 which is the backup system is selected.

Specifically, the transmission quality of the current system is significantly degraded,
The signal received by the receiving circuit 106 that is the standby system is
When the level becomes better than the signal received by the receiving circuit 105 of the working system, the receiving circuit 10 of the standby system 10
Switch to 6.

The above has described the uplink, but the same operation is performed for the downlink.

As a result, it is possible to configure a wireless transmission / reception device in fixed communication that can always output a stable reception level.

[Problems to be Solved] The above-described conventional 1 + 1 frequency diversity radio transmitter / receiver in fixed communication always operates two radio transmitter / receiver circuits even in a normal and stable propagation state. On the other hand, there is a problem that power is consumed to operate the two wireless transmission / reception circuits.

Although it varies depending on foreign countries, regions, distances, etc., the number of unstable propagation states (when fading occurs) is extremely small in terms of time compared to stable propagation states throughout the year.
It is usually about several percent. In spite of this, the conventional 1 + 1 frequency diversity radio transmitter / receiver in fixed communication must always operate two transmitter circuits having different frequencies.

In particular, at a relay station without a commercial power source, a highly reliable, long-term maintenance-free power source facility is desirable. However,
In order to supply more power, you have to use unreliable generators or large-scale photovoltaic power sources, which makes maintenance difficult and construction costs high. There was a problem.

The present invention has been made in consideration of the above problems, and it is possible to realize a fixed communication which is capable of stable transmission and reception with low power consumption.
An object is to provide a +1 frequency diversity radio transceiver.

[Means for Solving Problems] In order to achieve the above object, in the fixed communication of the present invention,
The +1 frequency diversity radio transmitter / receiver includes a transmission circuit and a reception circuit that form radio lines of two different frequencies, respectively, and a reception signal selection circuit that switches the reception signal output based on the reception level of the reception circuit. In a 1 + 1 frequency diversity radio transmitter / receiver in fixed communication, transmission and stop of at least one transmission circuit of the transmission circuits of the game transmitting the reception signal are controlled based on the reception level of at least one reception circuit. It has a configuration including a transmission control circuit.

[Embodiment] An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 shows 1 in fixed communication according to an embodiment of the present invention.
FIG. 3 is a block diagram of a +1 frequency diversity wireless transceiver.

In the figure, 1 and 11 are input terminals for wireless signals, 2 and 12 are output terminals for wireless signals, and 3, 4, 13, and 14 are frequencies f1a, f2a, and f, respectively.
1b, f2b transmitter circuit, 5,6,15,16 are frequency f1a, f2 respectively
The receiving circuits a, f1b, and f2b, and 7 and 17 are switching devices. And 2
0,21 is a reception signal judgment circuit (transmission control circuit) that also has a function of controlling ON / OFF of the power supply of the transmission circuits 3, 4, 13, 14; 30 and 40 are reception signal level information of the reception circuits 5 and 15 , 31,
Reference numeral 41 is a control signal for turning on / off the power supply of the transmission circuits 4 and 14.

In the above configuration, the signals input from the wireless signal input terminals 1 and 11 are two transmitter circuits 3, 4 or 13, respectively, of the own station.
Entered in 14. However, in normal times, the radio frequencies f1a and f1b
Only the power supply of the transmission circuits 3 and 13 using is turned on, and a radio signal is transmitted to the game. Then, the power supplies of the transmission circuits 4 and 14 for the other radio frequencies f2a and f2b are turned off.

Also, the signal is input from the input terminal 1 and is transmitted by the transmission circuit 3.
The signal of the radio frequency f1a transmitted to the game is received by the receiving circuit 5 of the game. Then, as the output of the reception signal, the switch 7 selects the signal of the reception circuit 5 of the active system.

The received signal level information (for example, received electric field information) 30 received by the receiving circuit 5 of the active system is sent to the received signal determination circuit 20. The received signal determination circuit 20 compares and determines a level (for example, a squelch level) preset based on the received signal level information. When the comparison result is large (that is, when fading has not occurred and the reception level is stable), the control signal 31 is set to the service baseband 50.
Is transmitted to the reception signal determination circuit 21 of the game, and the power supplied to the transmission circuit 4 of the game is continuously turned off. Then, the state in which the operation of the transmission circuit 4 is stopped is maintained.

On the other hand, when this comparison result is small (that is,
Conversely, the control signal
31 turns on the power supply of the transmission circuit 4. For this reason,
The transmission circuit 4 sends out a signal of the radio frequency f2a, and constitutes a 1 + 1 frequency diversity radio line in normal fixed communication for the uplink.

Further, in exactly the same manner, the reception signal determination circuit 21 determines the signal input from the input terminal 11 and passed through the transmission circuit 13 and transmitted toward the game, and the power supply of the transmission circuit 14 of the game is determined by the determination result. Turn supply on or off.

Therefore, when the received signal level is low, a 1 + 1 frequency diversity wireless line in normal fixed communication can be configured, and a stable received signal level can be obtained by the frequency diversity effect.

INDUSTRIAL APPLICABILITY As described above, the present invention monitors at least one received signal for two wireless transmission / reception circuits constituting a 1 + 1 frequency diversity wireless transmission / reception device in fixed communication,
When this level is higher than a preset level (eg, squelch level) (that is, when there is no fading in a stable propagation state), it is operated by means such as turning off the power of the radio transmission / reception circuit of the opposite station. On the other hand, when it is smaller than the set level (when fading occurs in an unstable propagation state), turn on the power of the power supply to activate the two radio transceiver circuits of the game. The control function is added.

This operation is the same as the operation of the device of the partner station that constitutes the 1 + 1 frequency diversity wireless line in fixed communication. In other words, for the devices of the two stations that make up the wireless link, most of the time during stable propagation is
Only one wireless transceiver circuit is operated. Therefore, the power consumed by the wireless relay device can be reduced to about half.

The specific effects of reducing power consumption according to the present invention are as follows.

As an example, the power consumption of one wireless transmitter / receiver manufactured by NEC Corporation, which has a radio frequency of 7 GHz, a transmission capacity of 34 Mb / s, and a transmission output of 1 W, is approximately 47 W. Then, it is assumed that 5% of fading occurs in one day. When the 1 + 1 frequency diversity radio transmitter / receiver in fixed communication according to the present embodiment is used in such a radio line, the power consumption of the standby system is 47 × 0.05 = 2.35 W. Comparing this with two relay stations that the 1 + 1 frequency diversity radio line opposes, 47 × 4 = 188 W in the conventional system, and 47 × 2 + 2.35 × 2 = when the system according to the present embodiment is used. It becomes 98.7W.

As described above, according to the present embodiment, it is possible to significantly reduce the power consumption.

[Effects of the Invention] As described above, according to the present invention, when the wireless transmission path is normal, fixed communication is performed by means such as turning off the power supply for operating one of the two wireless transmission / reception devices in the game. There is an effect that it is possible to reduce the power consumption of the transmission / reception device that constitutes the wireless relay circuit.

The propagation state of the wireless transmission path is bidirectional, and when the reception signal level of the local station is low, the reception signal level of the opposing station that opposes is also generally low. Therefore, the present invention also has an effect of improving the transmission quality.

[Brief description of drawings]

FIG. 1 shows 1+ in fixed communication according to an embodiment of the present invention.
A block diagram of a one-frequency diversity radio transceiver device,
FIG. 2 is a block diagram of a conventional 1 + 1 frequency diversity wireless transceiver in fixed communication. 3,4,13,14: Transmission circuit 5,6,15,16: Reception circuit 7,17: Switch 20,21: Reception signal judgment circuit (transmission control circuit)

Claims (1)

[Claims] 1. Fixed communication comprising a transmission circuit and a reception circuit which form radio lines of two different frequencies, respectively, and a reception signal selection circuit which switches the reception signal output based on the reception level of the reception circuit. At 1 + 1
In the frequency diversity radio transmitter / receiver, a transmission control circuit for controlling transmission and stop of at least one transmission circuit of the transmission circuits of the game transmitting the reception signal is provided based on the reception level of at least one reception circuit. A 1 + 1 frequency diversity radio transmitting / receiving apparatus in fixed communication characterized by the above.