JPH05122125A - Transmission power control system - Google Patents

Abstract

PURPOSE:To improve a BER against the depth value of fading. CONSTITUTION:The information of a receiving input level detected by AGC voltage or the like from a receiver 8 is converted into a digital signal by an A/D converter circuit 17, the digital signal is inputted to a digital signal processing circuit 11, multiplexed with a main digital signal and then digitally modulated by a modulator 12, the modulated signal is processed by frequency conversion and power amplification by a transmitter 13, and the processed signal is radiated to space by an antenna 6 through a transceiver 7. The signal from a receiving station 22 is received by an antenna 5 in a transmitting station 21, inputted to a receiver 14 through a transceiver 4 and converted at its frequency, the frequency-converted signal is digitally demodulated by a demodulator 15 and the receiving input level information of the receiving station 22 is extracted by a digital signal processing circuit 16 and inputted to a power control circuit 18. The circuit 18 compares the inputted receiving input level information with plural set points for the transmitting power of a transmitter 3 which have been previously inputted to a data storage circuit 19 and sends a control signal in accordance with the compared result to control the output level of the transmitter 3.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a transmission power control system.

[0002]

2. Description of the Related Art In a conventional transmission power control system, Bi caused by the influence of non-linear distortion generated by making the maximum value of transmission power higher than the linear region of the amplification characteristic of a power amplifier of a transmitter.
In order to reduce the deterioration of the t Error Rate (BER) characteristic, the transmission power is the same as that when the transmission power control is not performed.

[0003]

In the above-described conventional transmission power control method, when the maximum value of the transmission power is higher than that in the case where the transmission power control is not performed, if the power control is continuously performed, the power amplifier will not operate. There is a problem that the Fade Depth vs. BER characteristic is deteriorated when power is not controlled by linear distortion.

[0004]

According to the transmission power control method of the present invention, the detection information obtained by detecting the input level at the receiver of the opposite receiving station is fed back to the transmitting station of the own station and the detected information is used as the basis. In the transmission power control method for controlling the output level of the transmitter of the transmitting station, the transmitting station corresponds to a detecting means for detecting a fading depth value and a plurality of fading depth values determined in advance. And a setting means for setting the maximum value of the transmission power.

[0005]

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

FIG. 1 is a block diagram showing an embodiment of the present invention.

In FIG. 1, this embodiment comprises a transmitter station 21 and a receiver station 22 which transmit and receive signals to and from each other via antennas 5 and 6, and the transmitter station 21 performs digital signal processing for digitally processing the signals to be transmitted. A circuit 1, a modulator 2 for modulating a processed digital signal for transmission, a receiver 14 for receiving a received signal from a receiving station 22 via an antenna 5 and a duplexer 4, and a demodulated received signal. A demodulator 15, a digital processing circuit 16 for digitally processing the demodulated reception signal and sending it to the next device (not shown), and extracting reception input level information, and a transmission processing corresponding to a plurality of aliasing reception input levels. The data storage circuit 19 which stores the output level in advance, and the output level of the transmission corresponding to the reception input level are read from the data storage circuit 19 and output from the transmitter 3. The power control circuit 18 for controlling the bell
And a transmitter 3 for transmitting an electric wave into the air through the duplexer 4 and the antenna 5 at the output level set by the power control circuit 18, and the receiving station 22 is transmitted from the transmitting station 21. Receiver 8 for receiving the received radio wave via antenna 6 and duplexer 7, and demodulator 9 for demodulating the received signal
A digital processing circuit 10 for digitally processing the demodulated reception signal and sending it out; an A / D conversion circuit 17 for converting an analog signal of the reception input level detected by the receiver 8 into a digital signal; Via the digital processing circuit 11 for multiplexing the digital signal from the conversion circuit 17 and the main digital signal, the modulator 12 for modulating the multiplexed signal, the demodulated signal via the duplexer 7 and the antenna 6. And a transmitter 13 for transmitting to the transmitting station 21.

Next, the operation of this embodiment will be described.

Information on the reception input level detected by the receiver 8 (for example, the AGC voltage or the like) is A / D conversion circuit 17
Is converted into a digital signal by the digital signal processing circuit 11 and is input to the digital signal processing circuit 11, multiplexed with the main digital signal, digitally modulated by the modulator 12, frequency-converted and power-amplified by the transmitter 13, and the duplexer 7
It is radiated into the space by the antenna 6 via the.

The signal from the receiving station 22 is received by the antenna 5 of the transmitting station 21, and is passed through the duplexer 4 to the receiver 1.
4 is frequency-converted and then digitally demodulated by the demodulator 15, and the digital signal processing circuit 16 extracts the reception input level information of the reception station 22 and inputs it to the power control circuit 18.

In the power control circuit 18, the received input level information is compared with a plurality of set values of the transmission power for the transmitter 3, which are previously input to the data storage circuit 19, and control is performed according to the result. Transmit the signal, transmitter 3
Control the output level of.

FIG. 2 shows the receiver input level versus BER (Bi) with the transmission power of the transmitter in this embodiment as a parameter.
FIG. 7 is a characteristic diagram showing an example of a (T Error Rate) characteristic.

Generally, when the transmission power of the power amplifier of the transmitter is increased above the linear region in the input / output characteristic, the BER characteristic is deteriorated due to the non-linear distortion. Therefore, the transmission power of the transmitter is set to a level where the influence is small. It In this embodiment, the level is set to 0 dB.

FIG. 3 shows the propagation section attenuation amount (Fade) due to fading when the input level of the receiver is 0 dB when the relative transmission power level of the transmitter is 0 dB in this embodiment.
It is a characteristic view which shows an example of a (Depth) to BER characteristic.

In FIG. 3, this characteristic is a characteristic in which the horizontal axis is shifted to the left by an amount corresponding to an increase of a relative level based on the transmission output relative level 0 dB of the characteristic shown in FIG.

In this embodiment, the best Fade De
The pth vs. BER characteristic is obtained by tracing the leftmost side of each characteristic curve in FIG. 3 with the transmission output relative level 0 dB as a reference, and the result is shown in FIG.

This embodiment is the best Fa shown in FIGS.
In order to obtain the De Depth vs. BER characteristic, the data storage circuit 19 controls the transmission output relative level corresponding to the Fade Depth at each point of a, A, B, C and D shown in FIGS. Is stored in advance as a set value of.

[0018]

As described above, according to the present invention, the detection information of which the input level is detected by the receiver of the opposite reception station is fed back to the transmission station of its own station and the transmission station is based on the detection information. In the transmission power control method for controlling the output level of the transmitter, the transmitting station detects the fading depth value, and the transmission power corresponding to a plurality of predetermined fading depth values. Since the transmission power of the transmitter is controlled with respect to the value of the fading depth, the BER can be improved as compared with the conventional method.

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of the present invention.

FIG. 2 is a diagram showing an example of a receiver input level vs. BER (Bit Err) using the transmitter transmission power as a parameter in the present embodiment.
FIG. 6 is a characteristic diagram showing an example of an or rate characteristic.

FIG. 3 is a propagation section attenuation amount (Fade Dept) due to fading when the input level of the receiver is 0 dB when the relative transmission power level of the transmitter is 0 dB in the present embodiment.
FIG. 7H is a characteristic diagram showing an example of a BER characteristic.

4 is the best Fa in this example obtained from FIG.
FIG. 6 is a characteristic diagram showing an example of de Depth vs. BER characteristics.

[Explanation of symbols]

 1,10,11,16 Digital signal processing circuit 2,12 Modulator 3,13 Transmitter 4,7 Transmission / reception duplexer 5,6 Antenna 8,14 Receiver 9,15 Demodulator 17 A / D conversion circuit 18 Power control Circuit 19 Data storage circuit 21 Transmitting station 22 Receiving station

Claims (1)

[Claims] 1. The detection information of the input level detected by the receiver of the opposite receiving station is fed back to the transmitter station of the own station to control the output level of the transmitter of the transmitter station based on the detected information. In the transmission power control method, the transmitting station, a detecting means for detecting a fading depth value, a setting means for setting a maximum value of the transmission power corresponding to a plurality of predetermined fading depth values. A transmission power control method comprising: