JPH0356491B2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to an earth station transmission power control system, and particularly to a high-frequency earth station transmission power control system such as a sub-millimeter wave band where a master station and a plurality of slave stations communicate via one satellite. This paper relates to an earth station transmission power control method in a satellite communication system using frequencies.

[Conventional technology]

Satellite communication systems that use high frequencies, such as sub-millimeter wave bands, where transmission attenuation due to rain is extremely large, require transmission power control to compensate for uplink rain attenuation by controlling the earth station's transmission power. .

As an earth station transmission power control method in such a satellite communication system in which a master station and multiple slave stations communicate, the master station transmits a pilot signal whose transmission power is controlled so as to keep the effective radiated power of the satellite return signal wave constant. , JP-A-58-84544 discloses a method in which the slave station controls the transmission power based on the reception level of the satellite return signal wave of the received pilot signal or the carrier-to-noise power ratio (denoted as C/N). and Japanese Patent Application Laid-Open No. 58-84545. Also,
The reception level or C/
A method in which the master station controls the transmission power of pilot signals and communication signals by comparing N is disclosed in Japanese Patent Laid-Open No. 58-84547
It has become publicly known in the publication No.

In the method described in Japanese Unexamined Patent Publication No. 58-84544, transmission is performed using a control signal obtained from the reception level or C/N of the satellite return signal wave of the pilot signal and the correlation between uplink and downlink rain attenuation. The power is controlled to keep the effective radiated power of the satellite return signal wave of the communication signal transmitted by the own station constant. In the method described in Japanese Patent Application Laid-Open No. 58-84545,
The transmission power is controlled so that the reception level or C/N ratio of the satellite return signal wave of the pilot signal to the satellite return signal wave of the communication signal transmitted by the own station is equal to a certain reference value. In either method, in order to change the set value of the effective radiated power of the satellite return signal wave of the communication signal transmitted by the slave station, it is necessary to change the set value at the slave station.

[Problem that the invention seeks to solve]

Due to an increase or decrease in the number of slave station lines, an increase or decrease in the number of slave stations, or an error in the initial estimation of rainfall conditions, the setting value of the effective radiated power of the satellite return signal wave of the communication signal transmitted by the slave station may be changed. It happens often. In the conventional earth station transmission power control method described above, in this case it is necessary to change the setting value for each slave station, and this is difficult to do when there are a large number of slave stations or when the slave stations are located in difficult-to-access locations such as remote islands. The cost would be enormous due to adjustments at each subsidiary station.

As explained above, the conventional earth station transmission power control system has the drawback that it requires a huge amount of expense when changing the set value of the effective radiated power of the satellite return signal wave of the communication signal transmitted by the slave station.

An object of the present invention is to provide an earth station transmission power control method that allows changing the set value of the effective radiated power of a satellite return signal wave of a communication signal transmitted by a slave station without making adjustments at each slave station. be.

[Means for solving problems]

In the earth station transmission power control system of the present invention, at least one specific earth station among a plurality of earth stations communicating via one satellite includes a generating means for generating a pilot signal, and a generator for generating the pilot signal and a first earth station.
a first transmitting means capable of transmitting power control for transmitting the output of the combining means to the satellite, and a reference signal whose effective radiated power from the satellite is constant regardless of rain or shine. a reference signal receiving means for receiving a satellite return signal wave, a first pilot receiving means for receiving a satellite return signal wave of said pilot signal, said reference signal receiving means and said first
and a comparison control means for generating a signal for controlling the first transmitting means by comparing the output level or the carrier-to-noise power ratio of the pilot receiving means,
All or some of the earth stations other than the specific earth station receive a second transmission means whose transmission power is controllable for transmitting a second communication signal to the satellite, and a satellite return signal wave of the pilot signal. Earth station transmission power control comprising: second pilot receiving means; and control means for generating a signal for controlling the second transmitting means based on the output level or carrier-to-noise power ratio of the pilot receiving means. In the method, the comparison control means adjusts the level or carrier-to-noise of the signal input from the reference signal receiving means in response to changing the set value of the effective radiated power of the satellite return signal wave of the second communication signal. The generating means includes offset means for offsetting the power ratio or the level or carrier-to-noise power ratio of the signal input from the first pilot receiving means, and the generating means adjusts the output level of the signal to that of the first and second communication signals. The apparatus is configured to include an output level changing means that changes in response to changing the set value of the effective radiated power of the satellite return signal wave.

〔Example〕

The present invention will be described in detail below with reference to drawings showing embodiments.

FIGS. 1 and 2 are block diagrams showing a master station and a slave station according to an embodiment of the earth station transmission power control method of the present invention.

The master station shown in FIG.
) 2, a synthesizer (abbreviated as COMB) 3 that synthesizes and outputs the pilot signal 101 and a plurality of communication signals 102, and its output and D-
A variable gain amplifier (abbreviated as VGAMP) 4 inputting the output of the A converter (abbreviated as D/A) 26
and a transmission frequency converter (U/
A power amplifier (abbreviated as PA) 6 that inputs its output, an antenna (abbreviated as ANT) 7 that inputs its output, and a low noise amplifier (abbreviated as LNA) that inputs its output. abbreviated) 8
and a divider (HYB) that divides the output into two and outputs it.
) 9, a reception frequency converter (abbreviated as D/C) 10 that inputs one of its outputs, a beacon receiver (abbreviated as BCNREC) 12 that inputs its output, and an offset signal generator. (abbreviated as OFF SET) 15, a C/N detector (abbreviated as C/NDET) 14 to which its output and the output of BCNREC 12 are input, and an A-D converter (A/D and abbreviated) 17
and C/ which inputs the output and outputs the signal 103.
N corrector (abbreviated as C/NCOMP) 19;
D/C11 which inputs the other output of HYB9,
A pilot receiver (PILREC) inputs its output.
(abbreviated as ) 13 and C/ that inputs its output.
NDET16, A/D18 which inputs its output and outputs signal 104, signal 103 and signal 1
04, a sample clock oscillator (SAMPLCLK) 22, a gate circuit (GATE) 21 that inputs its output and the output of SUB20, and a register. (abbreviated as REG) 24, an adder (abbreviated as ADD) 23 that inputs the output and the output of GATE 21 and inputs the output to REG 24, and a nonlinear control voltage corrector (abbreviated as AMPCOMP) that inputs the output. 25, and a D/A 26 that inputs the output thereof.

The slave station shown in FIG. 2 includes a COMB 3a that synthesizes and outputs a plurality of communication signals 201, and a VGAMP 4a that inputs the output and the output of the D/A 26a.
, U/C5a that inputs that output, PA6a that inputs that output, and U/C5a that inputs that output.
ANT7a and LNA8a which inputs its output,
D/C11a inputting the output, PILREC13a inputting the output, C/NDET16a inputting the output, SAMPLCLK22a,
GATE21a inputs its output and the output of C/NDET16a, and inputs signal 202.
ADD23a that inputs REG24a, its output, and the output of GATE21a and outputs signal 202
, a transmission power controller (abbreviated as TPCCONT) 27 to which the signal 202 is input, and a D/A 26a to which the output thereof is input. In Figure 2, reference numbers with “a” added are the first
The operation as a single unit is the same as those having the same reference numerals in the figures.

First, the operation of the master station shown in FIG. 1 will be explained.

It is possible to change the attenuation setting that occurred in PILOS1.
Pilot signal 10 with level set at ATT2
1 is combined with the communication signal 102 for the slave station at COMB3, passes through voltage-controlled VGAMP4, is converted to a quasi-millimeter wave band at U/C5, and passes through PA6.
Sent from ANT7 to the satellite. On the other hand, the beacon signal wave from the satellite and the satellite return signal wave of the pilot signal 101 are received by ANT7, amplified by LNA8, and then divided into two by HYB9, one of which is sent to C/C through D/C10 and BCNREC12.
Enter NDET14. OFFSET15 is C/
The C/N output of NDET14 is set by the offset ratio that can be changed (the initial setting value is C ₁ ).
C Offset by _1x . The other output of HYB9 is connected to C/C through D/C11 and PILREC13.
Enter NDET16. After the logarithmically converted C/N outputs of the C/NDETs 14 and 16 are digitally converted by the A/Ds 17 and 18, one of them undergoes downlink attenuation due to the difference in frequency between the beacon signal wave and the satellite return signal wave of the pilot signal 101. The output is sent to SUB20 through C/NCOMP19, which corrects the difference in quantity, and the output is sent to GATE21 at regular intervals.
is sampled and sent to ADD23. ADD2
3 adds the input to the value stored in the REG 24 (the output of the ADD 23 at the time of the previous sample), outputs the result, and stores it in the REG 24 again. In this way, ADD23 and REG24 digitally integrate the output of GATE21. This integrated value digital signal is used to correct the nonlinear control voltage characteristics of VGAMP4 and improve the control characteristics of AMPCOMP2.
5 and D/A 26 to become a control signal for VGAMP4. As a result, the transmission wave of the pilot signal 101 radiated by the antenna 7 is so that the output of the SUB 20 becomes zero, that is, the signal 103 and the signal 10
The power is controlled so that the satellite input level becomes constant, and the effective radiation power of the satellite return signal wave of the pilot signal 101 can be made constant regardless of the presence or absence of rain.

The effective radiated power of the beacon signal wave is B, received C/
Let N be (C/N) _B , the effective radiated power of the satellite return signal wave of the pilot signal 101 be P, and the received C/N
If (C/N) _P , then P/B=(C/N) _P /(C/N) _B ...(1), and since the signals 103 and 104 are equal, (C/N) _B・C ₁ = (C/N) _P ...(2), and therefore P = B・C ₁ ...(3) Therefore, the master station shown in FIG. Keep the effective radiated power of the wave at C ₁ times the effective radiated power of the beacon signal wave.

The attenuation of ATT2 is set so that the power of the pilot signal 101 is P, the power of the communication signal 102 is t ₁ , and the effective radiation power of the satellite return signal wave is T ₁ , t ₁ = p・C ₂ ...(4) When initially set, T ₁ /P = t ₁ /P ... (5) Therefore, T ₁ = P・C ₂ = B・C ₁・C ₂ ... (6), and the satellite return signal wave of the communication signal 102 The effective radiated power of P is also constant regardless of the presence or absence of rain, and its level is maintained at _twice P as C.

Next, the operation of the station shown in FIG. 2 will be explained.

This slave station uses the transmission power control method described in Japanese Patent Application Laid-Open No. 58-84544, and the communication signal 201 for the master station is VGAMP4a/U/C5.
a. Transmitted from ANT7a to the satellite via PA6a. On the other hand, the satellite return signal wave of the pilot signal 101 of the master station shown in FIG.
3a and enters C/NDET16a. C/
The C/N output of the NDET 16a becomes a signal 202 which is sampled by the GATE 21a and then digitally integrated by the ADD 23a and REG 24a.

As already explained, the pilot signal 101
The effective radiated power P of the satellite return signal wave is kept constant regardless of the presence or absence of rain. Therefore, the received C/N depends on the downlink rain attenuation, and on the other hand, since the uplink and downlink rain attenuation are correlated, TPCCONT27
generates a signal from this correlation and signal 202 that compensates for uplink rain attenuation, which
It passes through A26a and becomes a control signal for VGAMP4a. As a result, the power of the transmission wave of the communication signal 201 radiated by the ANT7a is controlled to compensate for uplink rain attenuation, and the effective radiation power of the satellite return signal wave of the communication signal wave 201 (assumed to be T ₂ )
is constant regardless of the presence or absence of rainfall. The level depends on the correlation between the effective radiated power P of the satellite return signal wave of the pilot signal 101 and the rain attenuation of the uplink and downlink, and the setting of the TPC CONT 27. Therefore, it can be expressed as T ₂ = f (P) ... (7) or P = f ^-1 (T ₂ ) ... (8).

Now, the effective radiated power of the satellite return signal waves of communication signals 102 and 201 can be calculated from the initial setting values T ₁ and T _2.
When changing the setting to T' ₁ /T' ₂ , pilot signal 1
01 power p is the initial setting value T ₁・P′/(T′ ₁・
P) times, change the setting of the offset ratio of OFFSET15 to P'/P times the initial setting value.

However, P′=f ^-1 (T′ ₂ ) ...(8′). By changing these settings, the constant C ₁ of the two equations
changes to C ₁・P′/P, so the pilot signal 10
The effective radiated power of the satellite return signal wave of No. 1 is calculated from equation 3 as follows: B(C ₁・P′/P)=B・C ₁ (P′ ₁ /P)=P′ ₁ ……(3′). Therefore, the effective radiation power of the satellite return signal wave of the communication signal 201 is changed to T' ₂ from equation 8'. On the other hand, the constant C ₂ in equation 4 is C ₂・T′ ₁・P/
(T ₁・P′), so the effective radiated power of the satellite return signal wave of the communication signal 102 is P′ ₁・C ₂・T′ ₁・P/(T ₁・P′) from equations 6 and 3′. = P・C ₂・T′
₁ /T ₁ = T' ₁ ... (6'), and the setting is changed to T' ₁ .

In this way, the master station and
The slave station can transmit communication signals 102 and 102 by simply changing the setting values of ATT2 and OFFTSET15 in the master station.
The setting of the effective radiation power of the satellite return signal wave of No. 201 can be changed, and there is no need to change the setting value at the slave station.

In addition, in the master station shown in Figure 1, OFFSET
The offset with 15 is D/C10.
BCNREC12/A/D17 or C/NCOMP
Any one of 19 may be used, and D/C11.
PILREC13/C/NDET16 or A/D18
It is also possible to offset any one of them at a ratio opposite to that performed by the OFFSET 15. In addition, level detectors can be used instead of C/NDET14, 16, 16a in the master station and slave station shown in Figures 1 and 2.
Instead of using digital integration to create the VGAMP4/4a control signal, analog integration using a low-frequency wave generator or the like can be used. The slave station shown in FIG. 2 may use the transmission power control method described in Japanese Patent Application Laid-Open No. 58-84545, which has already been explained in the section ``Prior Art''.

Furthermore, the present invention can be used even when the master station is a plurality of stations including a backup station, and some of the slave stations may use a more complicated transmission power control method.

〔Effect of the invention〕

As explained in detail above, the earth station transmission power control method of the present invention allows the setting of the pilot signal power of the master station and the output level or C/N offset value of the beacon receiver or pilot receiver to be changed. Since the earth station transmission power control method of the present invention is used, it is possible to change the setting of the effective radiated power of the satellite return signal wave of the communication signal of the master station and the slave station without changing the setting at the slave station. .

[Brief explanation of drawings]

FIGS. 1 and 2 are block diagrams showing a master station and a slave station according to an embodiment of the earth station transmission power control method of the present invention.

Claims (1)

[Scope of Claims] 1. At least one specific earth station among a plurality of earth stations that communicate via one satellite comprises: generating means for generating a pilot signal; and generating means for generating a pilot signal and a first communication signal. combining means for combining; first transmitting means capable of controlling transmission power for transmitting the output of the combining means to the satellite; and receiving a reference signal wave whose effective radiated power from the satellite is constant regardless of whether it is rain or shine. comparing the output level or carrier-to-noise power ratio of the reference signal receiving means, the first pilot receiving means for receiving the satellite return signal wave of the pilot signal, and the reference signal receiving means and the first pilot receiving means; and a comparison control means for generating a signal for controlling the first transmission means, wherein all or some of the earth stations except the specific earth station transmit a second communication signal to the satellite. a second transmitting means capable of controlling transmission power; a second pilot receiving means for receiving a satellite return signal wave of the pilot signal; In the earth station transmission power control system, the earth station transmission power control method includes a control means for generating a signal for controlling the second transmission means, wherein the comparison control means includes a set value of the effective radiated power of the satellite return signal wave of the second communication signal. offset means for offsetting the level or carrier-to-noise power ratio of the signal input from the reference signal receiving means or the level or carrier-to-noise power ratio of the signal input from the first pilot receiving means in response to changing the reference signal receiving means; , the generating means is configured to change the output level to the first
and an earth station transmission power control system, comprising an output level changing means that changes in response to changing a set value of effective radiated power of a satellite return signal wave of a second communication signal.