JPS63301629A - Transmission power control method - Google Patents

Abstract

PURPOSE:To execute communication under a low transmitting power as much as possible by increasing the transmitting power of a transmitting station in response that the variation of a receiving signal to accompany a fading to be given to a line is increased and a receiving signal differential coefficient in a receiving station is over a prescribed value. CONSTITUTION:When the differential coefficient of a receiving signal received by a receiving station 16 comes to be larger against a prescribed value by a fading, control information are generated from a transmitting power control information output means 13 and inputted from an antenna 12 through an antenna 10 of a transmitting station 4 and a receiver 18 to a transmitting level control means 7. The transmitting level control means 7 responds to the control information and generates the change of a setting level of a transmitting power change means 6 so that the transmitting power level can be raised. With the recovery of the fading, by the transmitting level control means 7, the setting level of the transmitting power change means 6 is changed to a low transmitting power level. Thus, the transmitting power can be reduced.

Description

[Detailed description of the invention] [Summary] The transmission power of the transmitting station is set to a value sufficient to maintain sufficient line quality in normal times, and the degree of change in the received signal due to fading applied to the line increases, In response to the differential coefficient of the received signal at the receiving station exceeding a predetermined value, the transmitting station's transmission power is set to a value sufficient to maintain normal reception at the receiving station even if there is line loss due to the above-mentioned fading. increase to

[Industrial application field]

The present invention relates to a transmission power control method, and more specifically,
This invention relates to a transmission power control method that uses a differential coefficient of a received signal to control transmission power for power reduction, etc.

In wireless communication networks such as digital multiplex wireless communication, when attempting to transmit desired information from the transmitter to the receiver,
This information will be transmitted over radio waves. In order for the receiving side to successfully receive the radio waves, the radio waves must be radiated from the transmitting side to the receiving side with the necessary transmission power. For the transmission, the transmission power must be determined taking into account not only the transmission capacity of the transmitting and receiving system but also the state of the transmission medium. In addition, it is important to take into consideration the situation of other transmitting and receiving systems, whether existing or uninstalled, in the area where the transmitting and receiving system is being constructed, in order to maintain the various wireless communication systems in the area as they should be. It is a matter.

[Conventional technology]

A conventional digital multiplex wireless communication system was configured as shown in FIG. The transmission signal modulated by the modulator 2 on the transmitting side is frequency-converted from the IF band to the RF band by the transmitter 4. The output signal of the transmitter 4 is transmitted to the power amplifier 14
The power is amplified from the transmitting antenna 16 to the receiving antenna 3.
It is radiated towards 0. The signal received by the receiving antenna 30 is frequency-converted from the RF band to the IF band by the receiver 32, and then AGC-amplified by the AGC amplifier 34 and sent to the demodulator 36.
It is used for reproducing the transmitted signal.

The transmission power in such a transmission/reception system is determined by the AG on the receiving side.
Even when the gain adjustment function of the C amplifier 34 reaches its upper limit, the transmitting antenna 16 can still radiate radio waves of sufficient strength to maintain line quality. Previously, it was set.

[Problem that the invention seeks to solve]

However, although the above-mentioned transmission power setting is acceptable from the perspective of maintaining line quality, from the perspective of saving power, it may result in unnecessary large transmissions over a long period of time. This means that information is transmitted using electricity. This is because the transmission power set as described above is due to the large line loss (mainly loss due to fading) that only occurs for about 5 to 10 hours a year, and such large transmission power is not available at other times of the year. This is because, although this is not necessary, it is intended to maintain the desired line quality during the time period when large line losses as described above occur.

Further, the above-mentioned large transmission power does not pose a problem if there are no other transmitting/receiving systems in the area where the transmitting/receiving system is installed, but if this is not the case, it causes an inconvenience.

The present invention was created in view of such problems, and an object of the present invention is to provide a transmission power control method for performing communication at the lowest possible transmission power.

[Means for solving problems]

FIG. 1 shows a basic configuration diagram of the present invention. In this diagram,
2 is a transmitter of the transmitting station 4, 6 is a transmission power changing means for changing the transmission power level, and 7 is a transmission level control means. 10.12 is a transmitting/receiving antenna. 1
Reference numeral 3 denotes a transmission power control information output means connected to the receiver 18 of the receiving station 16 for outputting transmission power control information based on the relationship that the received signal differential coefficient exhibits with respect to a predetermined value.

The present invention is configured such that the transmission power of the transmission power changing means 6 is adjusted by the transmission level control means 7 which responds to transmission power control information from the transmission power control information output means 13.

[For production]

During communication with a relatively low fading rate, the transmission power changing means 6 transmits control information fed back from the transmission power control information output means 13 so as to perform transmission at a predetermined relatively low level of transmission power. The receiving transmission level control means 7 sets the level to that level, and radio waves are radiated from the transmitting antenna 10 of the transmitting station 4 toward the receiving antenna 12 of the receiving station 16, thereby performing the required communication.

When the differential coefficient of the received signal received by the receiving station 16 via the communication line becomes larger than a predetermined value due to fading, control information for increasing the transmission power is generated from the transmission power control information output means 13, and the reception The signal is input from the antenna 12 to the transmission level control means 7 via the transmitting antenna IO1 receiver 18. In response to the control information, the transmission level control means 7 causes the setting level of the transmission power changing means 6 to be changed so as to increase the transmission power level. and,
As fading recovers, the setting level of the transmission power changing means 6 is changed by the transmission level control means 7 to a lower transmission power level.

〔Example〕

FIG. 2 shows an embodiment of the invention. In this figure, 4
．． ．． 16. is a transmitting/receiving station, and 2.18 is a transmitter and a receiver of each transmitting/receiving station, respectively. 8 is a transmission level control circuit;
4 is a fading speed detection circuit. These circuits8.
Although reference numeral 14 is shown only at one transmitting/receiving station for clarity of the drawing, it is provided for each round.

The configuration of the transmitter 2 and the transmission level control circuit 8 is shown in FIG. The transmitter 2 includes an IF amplifier 21, a mixer 2□,
Transmission local oscillator 21, variable attenuator 24 and RF amplifier 2
．． (Between f+r and fTLr'T in the figure, l
ft fytl=f+r). The variable attenuator 24 shows an example of the configuration of the transmission power changing means 6 shown in FIG.
Give double signal to RF amplifier 2. This is to change the transmission power level. The analog voltage is output from the transmission level control circuit 8.
is a signal output from the command signal regeneration circuit 20 connected to the output of the AGC amplifier 18s of the receiver 18, for example, for reducing the attenuation amount in response to the high level signal "l" when there is a transmission power control command. For example, an analog signal is output for making the amount of attenuation zero, and when there is no amount of attenuation, an analog signal is output for increasing the amount of attenuation in accordance with the low level signal "°0".

The configuration of receiver 18 is shown in FIG. In this figure, the receiver 18 includes an RF amplifier 188, a mixer 18□,
Receiving local oscillator 1B, IF bandpass filter (IFB
PF) 1B, consisting of an AGC amplifier 18s. AGC
Amplifier 18s has an output l and an output 2, with output 1 connected to a demodulator (not shown) and output 2 connected to command signal regeneration circuit 20.

The fading speed detection circuit 14 detects the fading speed using a signal differential coefficient and outputs a transmission power control command, and the output signal is configured to be transmitted to the opposite station via the transmitter 2 of the local station. There is. The fading speed detection circuit 14 is connected to the AGC amplifier 18. of the receiver 18 described above. AGC of
Differentiating circuit 14 that receives control voltage □ Absolute value generating circuit 14 □
, comparison circuit 143. It consists of a knot circuit 144. The absolute value generating circuit 14□ has one input connected to the differentiating circuit 14. Operational amplifier 14Zt receives the output of , and receives zero voltage from the other human power
, a diode 14□2.1423 whose cathode is connected to the non-inverting output and the inverting output of the operational amplifier 14!1, the anode of the diode 14tg, and the anode of the diode 14!3 are connected to the operating type 't1. ■
It consists of a resistor 14□4 connected to the absolute value generating circuit 14.
The output of g is the diode 14□z, 14*z and the resistor 14□
This is the connection point with 4.

The transmission power control mode under the above configuration will be explained below.

Now, transmitting/receiving stations 41, 16. The transmission level control circuit 8 of
In a state where the differential coefficient of the received signal between the transmitting and receiving stations 4+ and 16+, that is, the fading rate, is below a predetermined value, the transmission power level is relatively low enough to raise the reception level to a predetermined value or higher. It is assumed that the antenna 10 or 12 is set to radiate radio waves toward the opposing station.

When in such a setting, the frequency flf to transmitter 2
The IF input signal of IF amplifier 2. amplified by mixer 2
□, and transmits the signal together with the transmitting local oscillator 2. The mixer 2t receives the local oscillation signal of frequency 17 from the RF multiplied signal lfv fttl'.
=f+r).

This RF double signal RF amplifier 2. The amplitude of the signal is attenuated by the analog signal from the transmission level control circuit 8 and input to the RF amplifier 2% so that the transmission power level supplied to the antenna 10 becomes the above-mentioned level. Thus, radio waves with the transmission power level set to the above-mentioned level are radiated toward the opposing station to perform the required communication.

Opposing station 16. is received by the antenna 12 of the RF amplifier 1.
The RF signal amplified at 81 is input to mixer 182,
The RF signal is transmitted along with the signal to a receiving local oscillator 18. Frequency fllL””f? The frequency is converted in the mixer 18□ which receives the local oscillation signal of L, and the frequency is flf!
F signal and passes through the IF bandpass filter 184 to A
Input to GC amplifier 18°. The IF multiplied signal is amplified to the output l and is inputted to a demodulator (not shown) and used for reproducing the transmission signal.

AGC amplifier 18. The AGC control voltage is determined by the differentiating circuit 14.
The differential coefficient signal of the voltage signal is output from there. This differential coefficient signal is a signal reflecting the differential coefficient of the received signal, that is, the fading speed, as shown in FIG. As can be seen from FIG. 6, the differential coefficient signal takes positive and negative values, so the absolute value generating circuit 14! Generate its absolute value from . The value is compared with a reference voltage r for fading speed in a comparison circuit 143. When the absolute value reaches r, a binary signal of high level "1" is output from the comparison circuit 14. Therefore, the NAND circuit 144 outputs a transmission power control command of "0'".

This command is 16. is transmitted to the opposite station 41 via the transmitter 2 and the antenna 12, and the antenna 1 of the opposite station 4°
0 is applied to the transmission level control circuit 8 via the receiver 18. Thus, the signal from circuit 8 maintains the transmission power level at a level that maintains line quality.

In such a transmission/reception state, when the rate of change in the received signal due to fading increases, the change in the level of the signal radiated at the above-mentioned set transmission power level and received at the opposite station also increases by the increase.

Therefore, as described above, the differentiating circuit 14. The differential coefficient signal output from this also increases. The signal from the absolute value generation circuit 14□ is sent to the comparison circuit 14. A signal of "0" is output from the output terminal. As a result, the NAND circuit 144 outputs a transmission power control command of "1". This command is also transmitted to the opposite station in the same manner as described above. In this case, the signal level given from the receiver 18 to the transmission level control circuit 8 is set to a high level "1".The transmission level control circuit 8 sends a signal to the variable attenuator 24 to reduce the amount of attenuation there, e.g. An unattenuated analog signal is generated. As a result, the transmission power level of the radio waves radiated from the antenna IO is increased, and the opposite station can receive the radio waves at a reception level that can maintain the line quality at a desired value.

The reduction in the transmission power level upon recovery from the reception level change due to fading occurs together with the loss of the transmission power control command of "1".

Note that in the above embodiment, two
Although an example is shown in which binary information "O" or "1" is used, transmission power control may be performed using other binary information formats, for example, changing to a multi-level adjustment format.Changes in transmission power can be made using variable power control. This may be caused by adjusting the amplifier.Alternatively, the reduction in the transmit power level described above may be caused by a time delay.

〔Effect of the invention〕

As described above, according to the present invention, according to conventional knowledge, the time during which transmission must be performed under high transmission power is only a relatively small amount of time per year. According to the method of the present invention, which maintains line quality by increasing the transmission power by 100%, it is expected that not only will it be possible to significantly reduce the transmission power, but also the degree of communication interference with other systems will be reduced and the allocation of radio waves to the area will be increased. can.

[Brief explanation of drawings]

Figure 1 is a diagram showing the principle of the present invention; Figure 2 is a diagram showing an embodiment of the present invention; Figure 3 is a diagram showing the configuration of a transmitter and transmission level control circuit;
5 is a block diagram of a receiver, FIG. 5 is a fading rate detection circuit diagram, FIG. 6 is a reception level fluctuation curve diagram, and FIG. 7 is a block diagram of a conventional digital multiplex radio communication system. 1 to 5, 2 is a transmitter, 4 is a transmitting station (transmission/reception station 4), 6 is a transmission power changing means (variable attenuator 2), and 7 is a transmission level control means (transmission level control circuit). 8), 10.12 is a transmitting/receiving antenna, 13 is a transmitting power control information output means (fading speed detection circuit 14), 16 is a receiving station (transmitting/receiving station 161), and 18 is a receiver.

Claims (1)

[Claims] In a wireless communication system in which a transmission signal is amplified by a transmitter (2) of a transmitting station (4) and radiated toward a receiving station (16) to perform a desired communication, the transmitting station (4) ) is provided in the transmitter (2) with a transmission power changing means (6) and a transmission level control means (7) for changing the transmission power; 18) for outputting transmission power control information based on the relationship that the received signal differential coefficient exhibits with respect to a predetermined value
13) is provided, and the transmission power changing means ( 6) A transmission power control method characterized by adjusting.