JPH04284035A - Transmission power control method - Google Patents

Abstract

PURPOSE:To reduce the quality reduction of lines when selective phasing is generated concerning the transmission power control method used for the multiple digital radio equipment of a multicarrier system. CONSTITUTION:A reception part A is equipped with a comparing part 5 to transmit a comparing output when a voltage outputted from a reception side AGC amplifying part 4 to amplify signals in peak and bottom frequency ranges is lowered than a set threshold value and a reception control part 6 having a memory part 65 to write a gain control amount to a decided transmission side AGC amplifying part 1, and a transmission part is equipped with a transmission control part 7 respectively. When the comparing output is impressed from the comparing part, a reception control part reads out the gain control amount from the memory part and transmits it to the transmission control part, and the transmission control part tries to change the gain of the correspondent transmission side AGC amplifying part only for an amount corresponding to the detected gain control amount.

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 method used in a multi-carrier digital multiplex radio device.

[0002] A digital multiplexing radio device using a multicarrier system frequency-converts, for example, six series of intermediate frequency band signals from a transmitter, amplifies them commonly, and sends them to a receiver at a predetermined transmission frequency and transmission power. do.

[0003] The receiving section performs the reverse processing to the transmitting section to extract the main signals of the six streams, but it has the characteristic that even if a failure occurs in one stream, the remaining main signals can be transmitted using the other streams. There is.

[0004] Here, when selective fading that occurs in a radio line moves from the highest transmission frequency to the lowest transmission frequency among six transmission frequencies, for example, it is necessary to reduce the deterioration in line quality due to this fading. is necessary.

[0005]

2. Description of the Related Art FIG. 5 is a block diagram of a conventional example, in which six carriers are used to transmit different main signals. Here, since the configuration of each series is the same as shown in the figure, the operation will be mainly explained for the series whose intermediate frequency is fIF1.

First, the modulation part MOD1 uses the input main signal D1 to generate a modulated wave of frequency fIF1 (for example,
A multilevel QAM wave) is generated and sent to an amplification section with automatic gain control (hereinafter abbreviated as AGC amplification section) 11.

[0007] The AGC amplifying section 11 amplifies the modulated wave to a preset output level and sends it to the combining section 21. This synthesis part contains the frequency f from the other five sequences.
Since the modulated waves of IF2, . . . , fIF6 are also added, they are combined and frequency multiplexed.

[0008] Then, on the frequency axis, frequencies fIF1,
A composite signal in which modulated waves of fIF2 . . . fIF6 are lined up is added to the transmitter section 22. Note that fIF1 <
Let fIF2 <...< fIF6. The transmission part converts the frequency to the transmission frequency (fRF1, fRF2,...fRF6) using an internal frequency conversion part (not shown), amplifies it to a predetermined transmission power, and then transmits the 6 multicarrier transmission signal to the wireless line. is sent to the other station via the .

[0009] The reception section 31 of the partner station converts the received signal into frequencies fIF1, fIF2, . . . fIF.
6 composite signals are taken out and sent to the distribution section 32. The distribution part converts the composite signal into a modulated wave of frequency fIF1,
The modulated wave of frequency fIF2 is divided into the modulated wave of frequency fIF6, and the corresponding AGC amplification section 41...
46.

[0010] Therefore, the AGC amplification section 41
After the modulated wave of fIF1 is amplified to a predetermined level, it is sent to the demodulation section DEM1, where the main signal D1 is extracted. Here, selective fading occurs in the wireless line, and for example, the frequency fRF1 → fRF2 →・
・→ fRF6 When it is assumed that the transmission frequency moves from a low transmission frequency to a high transmission frequency, the incoming level of the corresponding received signal gradually decreases, waveform distortion occurs, and the line quality deteriorates.

[0011]

[Problem to be Solved by the Invention] When it is assumed that selective fading occurs as described above and the transmission frequency moves from a low transmission frequency to a high transmission frequency, the incoming level of the corresponding received signal will sequentially decrease and There was a problem in that waveform distortion occurred and line quality deteriorated, but there was no way to improve this.

[0012] An object of the present invention is to alleviate deterioration in line quality when selective fading occurs.

[0013]

SUMMARY OF THE INVENTION FIG. 1 shows a block diagram of the principle of the present invention. In the figure, 1 is a transmitting side amplifying section that amplifies signals in different frequency ranges using the corresponding internal transmitting side automatic gain control amplifying section, and 2 is a transmitting side amplifying section that combines the outputs of the transmitting side amplifying sections and frequency multiplexes the signals. , is a synthesis part that generates multicarriers.

Reference numeral 3 denotes a distribution section that distributes the received multicarrier into signals in different frequency ranges, and 4 amplifies the output of the distribution section in a corresponding amplification section with automatic gain control on the receiving side. This is a receiving side amplification section that sends out a voltage corresponding to the incoming signal level.

[0015] 5 indicates that the voltage output from the receiving side automatic gain control amplification section that amplifies the signals in the highest frequency range and the lowest frequency range among the distributed signals has fallen below a set threshold value. It is a comparison part that sometimes sends comparison output.

Reference numeral 6 denotes a reception control section having a memory section in which a predetermined gain control amount for a predetermined amplification section with automatic gain control on the transmission side is written in accordance with the comparison output, and 7 is a transmission control section. .

When the comparison output from the comparison section is applied, the reception control section reads the corresponding gain control amount from the internal memory section and sends it to the transmission control section, and the transmission control section , the gain of the corresponding amplification section with automatic gain control on the transmitting side is changed by an amount corresponding to the detected gain control amount.

[0018]

[Operation] If the selective fading is assumed to move from the lowest frequency range to the highest frequency range or from the highest frequency range to the lowest frequency range, the present invention allows signals in the lowest frequency range and the highest frequency range to be The direction of movement of selective fading is detected by detecting which of the voltages output from the receiving AGC amplification section to be amplified becomes lower than a predetermined threshold.

For example, when the direction of movement of selective fading moves from the lowest frequency range to the highest frequency range,
First, the level of the lowest frequency range decreases, and the level of the highest frequency range remains the same, but then the level of the lowest frequency range recovers, and conversely, the level of the highest frequency range decreases.

[0020] Therefore, if the direction of movement of selective fading is known, the receiving side AGC receiving the incoming call level during selective fading, the transmitting side AGC corresponding to the amplification part
A gain control amount for the transmission side AGC amplification section, excluding the amplification section, is read from the memory section and sent to the transmission control section via the reception control section.

[0021] This is to leave the frequency range that is initially affected by selective fading as it is, and to reduce the effect on the transmission frequency range that will be affected from now on. Further, the information on the gain control amount is sent to the transmitting side using, for example, a line that transmits the main signal in the opposite direction.

Since the transmission control section changes the gain of the corresponding transmission side AGC amplification section in accordance with the detected gain control amount, deterioration in line quality can be reduced.

[0023]

[Embodiment] Fig. 2 is a configuration diagram of an embodiment of the present invention, and Fig. 3 is Fig. 2
(A) is the multicarrier spectrum on the receiving side when there is no selective fading,
(B) is a multicarrier spectrum when moving from the lowest frequency range to the highest frequency range, and (C) is a multicarrier spectrum when moving from the highest frequency range to the lowest frequency range.

Note that M1 in FIG. 2 is the spectrum of the signal in the lowest frequency range (hereinafter abbreviated as carrier M1).
, M6 is the spectrum of the signal in the highest frequency range, M
2 to M5 is the spectrum of the signal in the frequency range between them. Further, FIG. 4 shows a block diagram of an example of the reception control section in FIG. 2. In FIG.

Here, the same reference numerals indicate the same objects throughout the figures. The operation of FIG. 2 will be described below with reference to FIGS. 3 and 4, with the parts explained in the conventional example being briefly explained and the parts according to the present invention being explained in detail.

It is assumed that the receiving side AGC section 41 amplifies the carrier M1, and the receiving side AGC section 46 amplifies the carrier M6. First, as shown in FIG. 3(A), when selective fading does not occur in the wireless line, the voltages corresponding to the incoming signal levels output from the receiving side AGC amplification sections 41 and 46 have approximately the same value. , but these voltages are sent to the comparison section.

The comparison section 5 includes, for example, two receiving side AGCs.
It consists of two comparators that compare whether the voltage sent out from the amplifier has fallen below a threshold value. The threshold value is a voltage corresponding to a level that is a certain value lower than the incoming signal level when there is no fading.

Therefore, the comparison result is not sent from the comparing section 5, and the gain control signal is not transmitted to the transmitting side. next,
As shown in FIG. 3(B), selective fading appears in the lowest frequency range M1, and the receiving side AGC amplification section 41
A voltage lower than the threshold was output from the receiving AG.
It is assumed that a voltage having approximately the same value as above is outputted from the C amplification section 46.

The comparison section 5 sends the comparison result that the output of the AGC amplification section is lower than the threshold value to the reception control section 6. On the other hand, the reception control part shown in FIG. 4 includes (B) in FIG.
Or for the case (C), transmitting side AGC amplifying parts 12 to 16, or transmitting side AGC amplifying parts 11 to
15, the gain control amount to be sent to the memory section,
That is, it is stored in the ROM 65.

[0030] This gain control amount is obtained by actually measuring the probability of occurrence of the depth of selective fading that occurs in the radio line used, and using this to compensate for the depth of fading that occurs most frequently. Decide on various values.

Now, the CPU 62 is the interface 6
ROM 65 identifies that the comparison result input via ROM 65 is a voltage drop in the receiving side AGC amplification section 41.
The gain control amounts of the transmitting side AGC amplification sections 12 to 16 are read out from the transmitter side AGC amplification sections 12 to 16 and sent to the interface 64.

The interface 64 converts the data into a predetermined format and sends it to the transmission control section 7 via the reverse line. Therefore, the transmission control section detects this gain control amount, generates a corresponding gain control signal, and transmits the signal to the transmitting side AGC amplification section 1.
Increase the gain of 2 to 16.

This makes it possible to reduce the influence of fading even when selective fading moves from carrier M2 to carrier M6 as shown in FIG. 3(B). Note that if the output of the receiving side AGC amplifying section 41 is restored and the output of the receiving side AGC amplifying section 46 is reduced in the comparison section, it is assumed that selective fading has passed, and a signal for restoring the gain control amount is sent from the receiving control section 6. By sending it to the transmission control section 7, the original state is restored.

Furthermore, the operation in the case shown in FIG. 3(C) is the same as in the case in FIG. 3(B) except that the output from the receiving side AGC amplification section 46 becomes less than the threshold value. Here, in the above method, when selective fading occurs, regardless of the depth of the fading that occurs, a gain control amount that compensates for the depth of fading that occurs frequently is sent to the transmission control section. .

However, for example, if the relationship between the rate of decline in the incoming call level and the depth of fading is measured in advance, and several types of relationships between the gain control amount and the fading depth are stored in the memory using this measurement, it is possible to By determining the rate of decline in the incoming call level in the comparison section, more fine-grained gain control can be performed.

That is, when selective fading occurs,
Deterioration in line quality can be reduced.

[0037]

As described in detail above, according to the present invention, it is possible to reduce the deterioration in line quality when selective fading occurs.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of the principle of the present invention.

FIG. 2 is a configuration diagram of an embodiment of the present invention.

[Figure 3] Figure 3 is an explanatory diagram of the operation in Figure 2, where (A) is the multicarrier spectrum on the receiving side when there is no selective fading, and (B) is the spectrum moving from the lowest transmission frequency range to the highest transmission frequency range. (C) is the multicarrier spectrum when moving from the highest transmission frequency range to the lowest transmission frequency range.

FIG. 4 is a block diagram of an example of a reception control section in FIG. 2;

FIG. 5 is a configuration diagram of a conventional example, in which six carriers are used to transmit different main signals.

[Explanation of symbols] 1 Transmission side amplifier section
2 Synthesis part 3 Distribution part
4 Receiving side amplifier section 5 Comparison section
6 Reception control part

Claims (1)

[Claims] [Claim 1] Signals in different frequency ranges,
a transmitting side amplifying section (1) that amplifies in an internal corresponding amplifying section with automatic gain control on the transmitting side, and a combining section (2) that combines the outputs of the transmitting side amplifying section and frequency multiplexes to generate multicarriers. a transmitting section having a transmitter, and a distributing section (
3), and a receiving side amplifying section (4) which amplifies the output of the distribution section in a corresponding internal receiving side amplifying section with automatic gain control and sends out a voltage corresponding to the incoming level of each signal. In a multi-carrier digital multiplex radio system in which the receiving unit transmits signals using a radio line where selective fading occurs, the receiving unit receives signals in the highest frequency range and the lowest frequency range among the distributed signals. a comparison section (5) that sends out a comparison output when the voltage output from the amplification section with automatic gain control on the receiving side to be amplified falls below a set threshold;
A reception control section (6) having a memory section (65) in which a predetermined gain control amount for a predetermined transmission side amplification section with automatic gain control is written in advance in accordance with the comparison output; A transmission control section (7) is provided, and when the comparison output from the comparison section is applied, the reception control section reads out the corresponding gain control amount from the internal memory section and sends it to the transmission control section. A transmission power control method characterized in that the transmission control section changes the gain of the corresponding transmitting side automatic gain control equipped amplification section by an amount corresponding to the detected gain control amount.