JPH0334629A - Transmitting power control system for fixed microwave communication - Google Patents

Abstract

PURPOSE:To sufficiently follow a receiving level fluctuation of a receiving side by a concise control circuit by executing a control so as to raise transmitting power by one step by a quantity set in advance, in the case a receiving level becomes lower than a certain set level. CONSTITUTION:In a receiving level detector 10 of a receiving side, a receiving level is monitored, and information corresponding to its result is transferred to a transmitting side. In the case the receiving level of the receiving side becomes lower than a certain set value, the transmitting side executes a control so as to raise transmitting power by one step by a certain set quantity by a transmitting power control circuit 9. In such a way, the control circuit is simplified, and also, it does not occur that a hunting operation caused by a time delay of a receiving level fluctuation information transfer is derived, and the improvement effect becomes large.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to fixed microwave communications, and particularly to a method for controlling transmission power on a transmitting side in response to changes in reception level on a receiving side.

[Technology in the US]

In fixed microwave communication systems, the transmission power can only be output at a constant value within the range permitted by law.

Therefore, during normal times, communication is performed using a transmission power that is stronger than necessary, which may cause interference with the standardization route.However, when the received electric field decreases due to aging, etc., the transmission power is sufficiently strong to compensate for this. In some cases, it may not be possible to perform communication with a high transmission power. In order to prevent this, control can be considered in which the transmission power is kept low during normal times, and the transmission power is increased when the received electric field decreases due to aging or the like. Conventionally, as such a transmission power control method, there is a method in which received power information is transferred to a partner station and the transmission power is continuously controlled so that the received power becomes an appropriate value.

[Problem to be solved by the invention]

As mentioned above, conventional microwave communication transmitters always transmit with a fixed transmission power, which has the problem of wasting a lot of power and causing a large amount of interference to other stations. Ta.

In addition, the above-mentioned transmission power control method, which was devised to solve this problem, continuously changes the transmission level according to the reception level, but it cannot completely follow the actual rate of change of the seven asons. First, it is difficult to obtain a sufficient improvement effect, and in particular, the control circuit becomes complicated.

SUMMARY OF THE INVENTION An object of the present invention is to overcome these conventional problems and provide a practical transmission power control system that can sufficiently follow reception level fluctuations on the receiving side using a simple control circuit.

[! Means for Solving the Problem] According to the present invention, the above-mentioned object is achieved by the means described in the claims.

That is, the present invention sets reception level thresholds A, B, C')7ttf with the relationship A>B>C in a fixed microwave communication transmission/reception system, and receives (!
! On the side, the reception level is monitored, and if the reception level becomes higher than threshold A, information a is sent to the reception level.
When the reception level becomes lower than threshold B, the information is continued until the reception level becomes higher than threshold A or lower than threshold C. In this case, a means for transmitting information a to the transmitting side is provided, and when the transmitting side receives the information, the transmitting power is increased to a predetermined value, and when information a is received, the transmitting power is increased. This is a transmission power control method for fixed microwave communications that is equipped with a means to control the power back to the specified value.

[For production]

In a fixed microwave communication transmission/reception system, the present invention increases the transmission power by a preset amount -aW! when the reception level becomes lower than a certain set level. This is to control to increase the I.

That is, the receiving level detector on the receiving side monitors the receiving level, and information according to the result is transferred to the transmitting side. On the transmitting side, when the reception level on the receiving side becomes lower than a certain set value, control is performed to raise the transmission power by one level by a certain set amount.

Since the present invention employs such a control method, the control circuit is extremely simple, and since there is no disturbance caused by the time delay in transmitting received level fluctuation information, the improvement effect is also better than that of the conventional method. This can be expected to be thicker than when using this control method.

〔Example〕

Hereinafter, the present invention will be described in detail based on examples.

FIG. 1 is a block diagram showing an embodiment of a wireless communication device to which the present invention is applied.

In the figure, 1 is an antenna, 2 is a duplexer, 3 is a receiving high frequency filter, 4 is a frequency conversion section, 5 is an intermediate frequency amplification section, 6 is an AC 3 section, 7 is a converter 11 section, and 8 is a Tfi II
1 a signal separation section, 9 a transmission power control circuit, 10 a reception level detector, 11 a transmission high frequency filter, 12 a power amplification section, 13 a frequency conversion section, 14 a modulation section, and 15 a control signal insertion section. It represents.

The wireless communication device of this embodiment includes a transmitter/receiver duplexer 2, a reception high frequency filter 3, a frequency conversion section 4, an intermediate frequency amplification section 5, an AGC section 6, a demodulation section 7, a control signal separation section 8, and a reception level detector. 10 constitutes a receiving section, and a transmitter/receiver duplexer 2
, a transmission power control circuit 9, a transmission high frequency filter 11, a power tank@ section 12, a frequency conversion section 13, a variable a section 14, and a control signal insertion section 15 constitute a transmitting section.

The operation of the wireless communication device shown in FIG. 1 will be described below.

The reception input signal received by antenna 1 is sent to duplexer 2
, a reception high frequency filter 3, and a frequency converter 4, and are converted into an intermediate frequency band (IF band). This received MM signal in the intermediate frequency band is then inputted to the demodulation section via the intermediate frequency amplification section 5 and the AGC section 6. At this time, the reception level detector 10 detects the AGC voltage I: therefore, the reception level, compares it with a predetermined threshold, and sends a control signal for controlling the transmission power of the transmitting side of the other station according to the result. Output.

Then, in order to send this control signal to the other station,
The control signal is input to a control signal insertion section 15 located before the first section 14.

The control signal insertion section 15 inserts this control signal into the main signal and sends it to the other station via the modulation section 14, the frequency conversion section 13, the power amplification section 12, the high frequency transmission filter 11, the duplexer 2, and the antenna 1. Transfer to. The other station side also has the same equipment configuration as shown in Fig. 1, and the control signal sent from the transmitting side shown in Fig. 1 is separated from the main signal by the control signal separation section 8 located after the demodulation section 7, and then transmitted. Power is supplied to the power control circuit 9.

If the control signal is a request to increase the transmission power, the transmission power circuit 9 controls the power amplifier 12 to increase the transmission power by a set level.

FIG. 2 is a diagram for explaining the transmission power control algorithm of the present invention, where (&) indicates the operation on the receiving side, and (b) indicates the operation on the transmitting side of the partner station.

In the same figure, as thresholds of the reception level, A, B
, C are set, of which A corresponds to the transmission power control release level, B corresponds to the transmission power control start level, and C corresponds to the reset level indicating an abnormal state such as power cut off of the receiving device. It was established as

At the receiving side, the received level R(t) is compared with these thresholds to generate the corresponding transmit power control information.

That is, when R(t) > A, R(t) > B, or R'(t) > C, control information I is set to a'', which indicates that the transmission power is normal. , R(t)
>B but not R(t) >C, the control signal I
As "b" indicating that an increase in transmission power is requested,
Send this to the other station. That is, the reception level R(t
) is smaller than the threshold B, the reception level R(
The control information is set to 'b' until t) becomes higher than the threshold value A or smaller than the threshold value C.

In response to this, the transmitting side of the partner station performs control such that when I=a, the transmit power is returned to the original specified value, and when I=b, the transmit power is increased to a predetermined value.

〔Effect of the invention〕

As explained above, according to the present invention, in fixed microwave communication, it is possible to improve the reception condition more than the conventional method with respect to fluctuations in the reception electric field level due to aging and the like.

And since the control circuit can be made very simple,
This has the advantage that the device can be realized economically.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing an embodiment of a wireless communication device to which the present invention is applied, and FIG. 2 is a diagram illustrating an algorithm for controlling transmission power according to the present invention. 1... Antenna, 2... Transmitter/receiver duplexer, 3... Receiving high frequency filter, 4... Frequency, converter,
5...Intermediate frequency amplification section, 6...
... AGC section, 7 ... Demodulation section,
8... Separation unit that receives control, 9 ・
...Transmission power control circuit, 10 ... Reception level detector, 11 Transmission high frequency filter, 1 Power amplification section, frequency conversion section, modulation section, control signal insertion section

Claims (1)

[Claims] In a transmission/reception system of fixed microwave communication, reception level thresholds A, B, and C having the relationship A>B>C are set respectively, and the reception level is monitored on the reception side. When the reception level becomes higher than threshold A, information a is sent, and when the reception level becomes lower than threshold B, the reception level becomes higher than threshold A or the threshold A means is provided for transmitting information b to the transmitting side until the received level becomes lower than threshold C, and information a when the reception level becomes lower than threshold C, and when the transmitting side receives the information b. A transmission power control system for fixed microwave communication, characterized in that the transmission power is controlled to increase the transmission power to a predetermined value, and to return the transmission power to the specified value when information a is received.