JPS63227222A - Transmission power control system - Google Patents

Abstract

PURPOSE:To save a transmission power, by supplying a transmission power control quantity to a variable power amplifier, a distortion component gain control quantity to a variable gain apparatus, and a distortion component phase control quantity to a variable phase shifter, corresponding to a bit of power control information. CONSTITUTION:In a state set so as to radiate a wave with a certain transmission power from a transmission antenna 16, the distortion component gain control quantity V and the distortion component phase control quantity V required for the negation of the distortion of the variable power amplifier 14 with negative phase relation in a set transmission power are supplied from a control means 19 to the variable gain apparatus 10 and the variable phase shifter 12. Therefore, in the transmission power, no distortion appears in the output of the amplifier 14. When the fluctuation of line loss occurs while power transmission is performed under the transmission power, the control means 19 supplies the transmission power control quantity Vp to the amplifier 14, and an adjusting signal is supplied from the control means 19 to the variable gain apparatus 10 and the variable phase shifter 12 so as not to generate the distortion in the amplifier 14, and thereby, the distortion of the amplifier 14 in the transission power can be offset. In such a way, it is possible to save the transmission power.

Description

[Detailed Description of the Invention] [Summary] A distortion compensation circuit that detects the distortion that occurs when transmitting power is changed in response to received power level information, and is provided in front of a transmitting power amplifier for only the detected distortion component. The amount of compensation has been corrected.

[Industrial application field]

The present invention relates to a transmission power control method, and more specifically,
The present invention relates to a transmission power control method that uses correction of the compensation amount of a distortion compensation circuit to suppress distortion that occurs due to a change in transmission power.

In a digital multiplex wireless network as well as a wireless communication network, when desired information is to be transmitted from a transmitting side to a receiving side, the information is sent on radio waves. In order to successfully receive the radio waves at the receiving end, the radio waves must be radiated from the transmitting end to the receiving end with the necessary transmission power. For 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 state of other transmitting and receiving systems, whether existing or not, in the area where the transmitting and receiving system is being constructed, in order to develop 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. On the transmitting side, the transmitting signal modulated by the modulator 2 is transmitted from the IF band to the RF by the transmitter 4.
11F, frequency converted. The output signal of the transmitter 4 is power amplified by the power amplifier 14 and radiated from the transmitting antenna 16 to the receiving antenna 30. 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 subjected to AGC amplification by the AGC amplifier 34, and then provided to the demodulator 36 to reproduce 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 strong enough to maintain line quality. Previously, it was set.

A power amplifier 14 is used that causes no distortion in the transmitted signal at that transmission power.

[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 emotions are being 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.

If this is the case, it would be sufficient to change the transmission power according to the situation on the receiving side, but simply controlling the transmission power would cause factors that would undermine the purpose of transmission and reception. In other words, the problem is distortion that occurs in high power amplifiers as the transmission power changes.

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 that can variably set transmission power without transmission distortion.

[Means for solving problems]

FIG. 1 shows a basic configuration diagram of the present invention. In this diagram,
Reference numeral 6 denotes a distortion compensation circuit consisting of a distortion generator 8, a variable gain unit 10, and a variable phase shifter 12, which constitutes the main part of the present invention. A feature of the present invention is that the phase of the phase shifter 12 is adjusted by the control means 19 by a value sufficient to cancel out the distortion generated in the variable power amplifier 14 as the amplification power of the variable power amplifier 14 is changed. For this purpose, in response to the power control information from the power control information reporting means 47, the control means 19 controls the variable power amplifier 14 with a transmission power control amount (■), and the variable gain unit 10 with a distortion component gain control amount (■). is configured to supply the distortion component phase control amount ■θ to the variable phase shifter 12. The power control information includes received power level information and distortion information, but the distortion information may be obtained from the variable power amplifier 14.

Note that 16.46 is a transmitting antenna, 22.30 is a receiving antenna, and 41 is a power control information output means.

[For production]

In a state where radio waves are set to be radiated from the transmitting antenna 16 with a transmitting power of and distortion component phase control amount■
θ is from the control means 19 to the variable gain lO and the variable phase shifter 1.
2. Therefore, no distortion appears in the output of the amplifier 14 at the above transmission power.

During transmission under that transmission power, if the line loss fluctuates, for example increases, and received power level information 11 is provided from the power control information reporting means 47 to the control means 19, the control means 19 Transmission power side to determine whether it is within the range and increase the transmission power? II amount V, is given to the intensifier 4.

As a result, the transmission power output from the amplifier 14 is increased. If distortion occurs in the amplifier 14 as a result, that information is transmitted from the power control information output means 41 to the control means 19, and distortion compensation is performed so as not to cause distortion in the amplifier 14 at the increased transmission power. An adjustment signal for correcting the compensation amount of the circuit (6) is transmitted from the control means (19) to the variable gainer (10) and the variable phase shifter (10).
2) to cancel the distortion of the amplifier 14 in the transmission power.

Conversely, when the reception power level increases, the transmission power decreases, but the distortion control method of the amplifier 14 in this case is almost the same as described above.

〔Example〕

FIG. 2 shows an embodiment of the invention. In this figure, 2
is a modulator, 4 is a transmitter, 6 is a distortion generator, 8° variable attenuator 1
0 and a variable phase shifter 12; 14 is a variable power amplifier (AGC amplifier); 16 is a transmitting antenna;
8 is a control device that generates the transmission power control amount VW, distortion component gain control fl va a, and distortion component phase control amount ■θ under program control, and 20 is a radio device (including the control device 18). ) and 22 are receiving antennas, and these components constitute a transmitting system. The receiving system for this transmitting system consists of the following components. 30 is a receiving antenna that receives radio waves from the transmitting antenna 16, 32 is a receiver, 34 is an AGC amplifier, 36
38 is a distortion detector, 38 is a demodulator, 42 is a control device, 44 is a wireless device, and 4G is a transmitting antenna. Part 32, 34.
36, 42, 44.46 and 22 correspond to 47 in FIG.

The manner of controlling transmission power in this configuration will be described below.

The transmission signal modulated by the modulator 2 is frequency-converted from the IF band to the RF band in the transmitter, and is directly transmitted to the variable power amplifier 1.
A signal for canceling the amount of distortion determined according to the amplification degree of the variable power amplifier 14 is supplied to the distortion generator 8.4 of the distortion compensation circuit 6. It is generated using a variable attenuator 10 and a variable phase shifter 12. For that purpose, the distortion component gain side rBfft
V P and the distortion component phase control amount ve are generated by the control device 18, and the transmission power control amount V determines the amplification degree.

Again, the control device! Generated from 1B.

The variable power amplifier 14 amplifies the composite signal of the output signal from the transmitter 4 and the signal from the distortion compensation circuit 6 according to the transmission power control amount V, and the amplified signal is transmitted to the transmission antenna 1.
6 toward the receiving antenna 30.

The signal received by the receiving antenna 30 is converted to RF by the receiver 32.
The signal is frequency-converted from the band to the IF band, passed through the AGC amplifier 34 and the distortion detector 36, and sent to the demodulator 38, where it is used to reproduce the transmission signal. At this time, received power level information is detected from the amplifier 34, and distortion components are detected from the distortion detector. This information is sent to the transmitting side via the control device 42, the wireless device 44, and the receiving antenna 46.

In this way, the received power level information and distortion information sent from the receiving side are sent to the receiving antenna 22. The signal is provided to the control device 18 via the wireless device 20.

In the control device 18, in response to the received power level information (31 in FIG. 3) detected and sent, the received power level falls within a preset reference range (for example, -30d).
If the determination is affirmative, the distortion component indicated by the detected and sent distortion component information (33 in FIG. 3) is determined. If it is below the standard, no changes are made to the above-mentioned transmission status.

If the received power level is outside the reference range mentioned above, this will cause a change in the transmit power.

That is, if the received power level exceeds the upper limit of the reference range, the control device 18 changes the transmit power control I V PO value in the direction of lowering the transmit power (85 in FIG. 3), and conversely changes the received power level is below the lower limit of the reference range, the control device 18 changes the value of the transmission power control 1vp in the direction of increasing the transmission power (86 in FIG. 3).

When such a change operation is proceeded and the received power level falls within the above-mentioned reference range (Y at 82 in FIG. 3),
If the distortion component from the receiving side is below the above-mentioned reference value in the transmission state, the transmission state is continued. If the distortion component exceeds the reference value (N at 86 in FIG. 3), the control device 18 responds to the distortion component by controlling the distortion component gain control amount ■ in a direction to reduce it below the reference value. and distortion component phase control lve are generated, and these are supplied to the corresponding controller to produce the control (87 in Fig. 3).This control continues until the distortion component from the receiving side becomes below the reference value. When the distortion level is reached (Y at 84 in FIG. 3), control is stopped and transmission continues in these control states.

In addition, in the above embodiment, an example was shown in which distortion occurring in the variable power amplifier (AGC amplifier) 14 due to a change in transmission power is detected on the receiving side. It may also be performed in a power amplifier. In addition, although we have shown an example in which the transmitting side determines whether or not the transmit power level is within the reference range, this determination is made on the receiving side and the information is sent to the transmitting side to control both of the above-mentioned control variables. . , V6 may be generated.

〔Effect of the invention〕

As described above, according to the present invention, transmission power can be significantly reduced while substantially eliminating distortion of a transmission signal. It is possible to reduce the degree of communication interference with other systems and increase the distribution of radio waves to the area.

[Brief explanation of drawings]

FIG. 1 is a diagram showing the principle of the present invention, FIG. 2 is a diagram showing an embodiment of the present invention, FIG. 3 is a control flow diagram, and FIG. 4 is a diagram showing the configuration of a conventional digital multiplex wireless communication system. 1 and 2, 6 is a distortion compensation circuit (distortion generator 8, variable gain device IO1 variable phase shifter 12), 14 is a variable power amplifier, 16 is a transmitting antenna, and 19 is a control means (control device 18). , wireless device 20), 30
47 is a receiving antenna, and 47 is a transmission power control information reporting means (power control information output means 41, transmitting antenna 46, and receiving antenna 22).

Claims (1)

[Claims] In a wireless communication system in which a transmission signal is amplified by a power amplifier and radiated toward an opposing station to perform the desired communication, the power amplifier is comprised of a distortion generator (8), a variable gain unit (10), and the like. ) and variable phase shifter (
A variable power amplifier (14) amplifies a composite signal of a transmission signal distortion-compensated and an uncompensated transmission signal by a distortion compensation circuit (6) consisting of 12), and a transmission power control information notification provided at the opposite station. said variable power amplifier (
Distortion detection means (41) provided in the transmission power control information reporting means (47) detects the distortion that occurs in the variable power amplifier (14) when the transmission power output from the variable power amplifier (14) is changed.
A transmission power control system characterized in that the variable gain device (10) and the variable phase shifter (12) are adjusted to a predetermined value or less according to a distortion component from the transmission power.