JPS63199525A - Control system for earth station transmission power - Google Patents

Abstract

PURPOSE:To prevent the control operation from being unstable even with a short response time by receiving a pilot signal sent reflectedly from a space station, detecting a reception level or a carrier versus noise power ratio and controlling the output in response to the reception level of a beacon signal or the ratio with respect to the carrier versus noise power ratio. CONSTITUTION:An output of a power amplifier 5 is sent to a space station as a communication signal Utc and a pilot signal Up to receive a communication signal Dr relayed by the space station, the reflected pilot signal Dp and the radiated beacon signal Db. A pilot signal Ipt becomes a pilot signal Up without passing through a variable gain amplifier 2. As a result, the effective radiated power of the pilot signal Up is a constant value independently of a control signal C1. Although the transmission power is controlled with high accuracy by using a pilot signal reflected from the space station, since no closed loop is employed, the control operation is not made unstable whatever a short response time of the control operation is to be adjusted.

Description

[Detailed Description of the Invention] [Industrial Field of Application] The present invention relates to the earth station transmission power system, and in particular to a universal earth station transmission power control system that compensates for the fallout in the rain area of a satellite communication system. Regarding the expression.

[Conventional technology]

In satellite communication systems that use light frequencies such as the sub-millimeter wave band, where the propagation path attenuation due to rainfall is extremely large, a. A double power system is required.

Figure 2 shows the first example of the conventional earth station transmission power control system.
It is a block diagram showing an example.

The conventional example shown in FIG. 2 includes a variable gain amplifier 2, an upconverter 4, a power amplifier 5, an antenna 6, a low noise amplifier 7, a hybrid 8, a downconverter 9.
10, a beacon signal receiver 11, and a control signal output circuit 15.

A communication signal It in an intermediate frequency band to be transmitted to a partner earth station (not shown) is amplified by a variable gain amplifier 2 whose gain is controlled by a control signal C3, and becomes a communication signal Itc. This signal is frequency-converted to the uplink frequency band by an upconverter 4 and a power amplifier 5. It is transmitted via the antenna 6 to a space station (not shown) as a communication signal Lltc.

The communication signal IJr in the downlink frequency band transmitted by the partner earth station and relayed by the space station is input to the down converter 10 via the antenna 6, low noise amplifiers 7.7 and IBRID 8, and the frequency is converted into the intermediate frequency band. It is converted and output to the outside as a communication signal Ir.

By the way, the space station radiates beacon signals in the downlink frequency band at a certain level for the purpose of antennas, tigers, kings, etc. of the earth station. This beacon signal is sent to the low noise amplifier 7. as a beacon signal Db. The signal is input to the down converter 9 via the high preamp and decoder 8, and is frequency-converted to an intermediate frequency band.

This becomes the beacon signal Ib. The beacon signal receiver 11 is
Level signal Lb indicating the input level of beacon signal Ib (this level corresponds to the received electric field of beacon signal Db)
Output.

1 between the antenna 6 and the space station. The propagation loss in the blink frequency band is Au, the propagation loss in the link frequency band is Ad, and the effective radiated power of the beacon signal is 81
If the received electric field is Db, Db=B/Ad
・・・・・・ (1) Lb=KIDb child,
B/Ad (2) K: It becomes a constant, and the change in Ad can be determined from the change in Lb. Since there is a correlation between the increase in Au due to rain attenuation and the increase in Ad, which is determined by the frequency of the a, green link, and downlink, the change in Au can be estimated from the change in Ad.

The control signal output circuit 15 estimates the change in Au from the change in Lb and the above-mentioned correlation, and outputs a variable gain using the control signal Cs so that the effective radiation power of the communication signal Utc increases or decreases by the same amount as the increase or decrease in Au. The gain of amplifier 2 is controlled. As a result, the rain attenuation of the Arab link is compensated and the communication signal υ
The received electric field at the tc space station is kept constant.

As explained above, the conventional example shown in FIG. However, since this correlation involves errors, the accuracy of the electric power charge is poor.

A second conventional example, which will be described next, improves accuracy by directly determining rain attenuation of A and Grink.

FIG. 3 is a diagram showing the second conventional example.

The conventional example shown in FIG. 3 is the same as the conventional example shown in FIG. Hybrid 12.
It is constructed by adding a pilot signal receiver 13 and replacing the control signal output circuit 15 with 16.

A pilot signal generator 1 generates a pilot signal Ipt for i-number bands of intermediate stations.

The communication signal It and the pilot signal Ipt are combined by a high frequency amplifier 3, amplified by a variable gain amplifier 2 to form a communication signal Itc and a pilot signal Iptc, and frequency-converted to an uplink frequency band by an upconverter 4. Power amplifier5. Communication signal Ut to the space station via antenna 6
c, transmitted as pilot signal Llpc.

The pilot signal Dpc, which is a signal obtained by returning the pilot signal Upc via the space station, together with the communication signal Dr,
Antenna 6, low noise amplifier 7. The signal is input to the down converter IOK via the high preamplifier 8, frequency-converted to an intermediate frequency band, becomes a pilot signal Iprc, and is input to the pilot signal receiver 13 via the hybrid 12.

- The communication signal Ir output from the down converter 10 is output to the outside via the hybrid 12.

The pilot signal receiver 13 receives a pilot signal I pr
A level signal Lp! indicating the input power level of c (this level corresponds to the received electric field of the pilot signal Dpc). Output. - In the same way as in the conventional example shown in FIG. 2, the beacon signal receiver 11 outputs the level signal Lb. And if Ga is the aliasing gain of the space station, then D pc = U pc G s / Au Ad
−・−・−(3) L pg = to * U pc /
Au Ad = (4)K! : Becomes a constant. From formulas 2 and 4, L b / L pz = KIB Au / Kg U p
cGs...(5) Equation 5 shows that Au can be directly determined from L b /L pt and Upc.

The control signal output circuit 16 has Lb/Lp as a constant of 3.
The control signal C! variable gain amplifier 2
Controls the gain of -C1Upc. the result,
From formula 5, the received electric field L of the pilot signal Upc at the space station
Upc/Au) is [Jpc/Au = KI 87Kg Km Gg
”...(6).Since KAu and Ad on the right side of equation 6 are not included, it is clear that the pilot signal can be sent to space 4 manually with a constant received electric field regardless of the presence or absence of rainfall. The communication false signal Utc is also OT variable gain amplifier 2, K 1ti111111, which is the same as pilot No. 48 Llpc.
1, so the received electric field at the space station will also be small.

As explained above, in the conventional example shown in FIG. 3, by using the pilot signal returned by the space station, it is possible to achieve good transmission power between the axes.

The pilot signal and the side landing gear signal C2 form a closed loop via the space station, and the response time of the braking operation due to this closed loop, including the return propagation time between the antenna 6 and the space station, is If the time is not increased to 6 degrees for several seconds, the control operation will become unstable.

[The problem that the invention attempts to solve]

As explained above, the conventional earth station transmission power system is
The objective of the present invention is that the degree of control is poor, or else the response time of the control action is too long to compensate for rapid fluctuations in rainfall attenuation. The objective is to provide an earth station transmission power system with short response times.

[Means for solving problems]

The earth station transmission power charge type of the present invention includes a pilot signal generation means for generating a pilot signal, a level control means for controlling the level of the C communication signal based on the Ij1 signal, and this level control means. a combining means for combining the communication signal and the pilot signal output by the combining means; a transmitting means for transmitting the communication signal and the pilot signal output by the combining means to a space station;
pilot signal receiving means for receiving the pilot signal returned via the space station and detecting a reception level or a carrier-to-noise vehicle power ratio; and a pilot signal receiving means for receiving a beacon signal in a communication frequency band emitted by the space station. , a beacon signal receiving means for detecting a reception level or a carrier-to-noise power ratio, and a control signal output for outputting the control signal according to the ratio of the detection signal of the beacon signal receiving means and the detection signal of the pilot signal receiving means. and means.

〔Example〕

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

FIG. 1 is a block diagram showing an embodiment of the earth station transmission gravity control method of the present invention.
A pilot signal generator 1 that generates a pilot signal Ipt, and a communication signal engineer t.

A variable gain amplifier 2 which inputs a control signal C1 and outputs a communication signal Itc, a communication signal Itc, and a pilot signal Ipt.
An analog converter 4 and a power amplifier 5 are connected in sequence to the output terminals of the high power converter 4 and the power amplifier 5.
and an antenna 6 that transmits the output of the power amplifier 5 to the space station as a communication signal Utc and a pilot signal Up, and receives a communication signal Dr relayed by the space station, a folded pilot signal Dp, and a radiated beacon signal Db. and a low-noise amplifier 7 sequentially connected to the reception output terminal of the antenna 6. Hipuri.

A down converter 9 inputs the branch outputs of 8, 8, and 10,000 and outputs a beacon signal Ib, and a down converter 9 inputs the other branch output and outputs a communication signal Ir and a pilot signal Ipr.
and a down converter lO that outputs a beacon signal Ib.
beacon receiver 11 which inputs the level signal Lb and outputs the level signal Lb.
, a hybrid 12 which inputs the output of the down converter IO, and a pilot signal receiver 13 which inputs the 10,000 branch outputs of the high-precision 12 and outputs a level signal Lp1.
and a control signal output circuit 14 which inputs level signals Lb and Lp and outputs a control signal C1.

The configuration of the embodiment shown in FIG. 1 differs in the control signal output circuit and the variable gain amplifier 2. The configuration is the same as that of the conventional example shown in FIG. 3, except that the front and back relationship of the hybrid 3 is reversed.

The pilot signal Ipt is the same as in the conventional example shown in FIG. 3, except that it does not pass through the variable gain amplifier 2.
The pilot signal becomes Up. As a result, the effective radiated power (expressed as Up) of the pilot signal Up is II
It becomes a constant value regardless of the Jilil signal CIK.

The communication signal It is level-controlled by the control signal CIK in the variable gain amplifier 2, and becomes the communication signal Utc as in the conventional example shown in FIG. Level signal Lb, Lp
Similarly to the conventional example shown in FIG. 3, l indicates the received electric field Db, DJ) (the received electric field of the pilot signal Dp).

The levels of the pilot signal Ipt and communication signal Itc are set to Ip.
t, Itc, Utc=Up Itc/Ipt
・・・・・・ (Also, similar to formula 5, Lb/Lpl=KI B Au /Kz Up Gs・
...(8) becomes.

The control signal generator 14 generates I tc =4 Lb/L J)t
＋＋＋＊＊＋ (9) K4: Variable gain amplifier 2 according to the control signal CIK so that it becomes a constant.
control the gain of. As a result, the received electric field (Utc/Au) of the communication signal Utc at the space station is obtained from equations 7 to 9 as follows: Utc/Au=KI K48/, Gs I pt・
・・・・・・ QQ becomes. Since Au and Ad are not included in the right side of Equation 10, it can be seen that (Utc/Au) is kept at a constant value regardless of rain attenuation.

As explained above, the embodiment shown in FIG. 1 also uses the pilot signal returned by the space station, and can control the transmission power with high accuracy in the same manner as in the conventional example shown in FIG. Since there is no closed loop as in the conventional example shown in FIG. 3, the control operation will not become unstable no matter how long the response time of the control operation is.

Note that the received electric fields Db and Dp and the beacon signal Ib.

Since it can be considered that the C/N of the pilot signal 1pr is proportional to the C/N of the pilot signal 1pr, the beacon signal receiver 11. The pilot signal receiver 13 receives Ib and I instead of the level signals Lb and Lpt.
You may also use K to output the C/N of pr. If you do this, the down converter 9.10 and the rice noodle signal receiver 11. The influence of gain fluctuations of the pilot signal receiver 13 can be reduced.

〔Effect of the invention〕

As explained in detail above, the earth station transmitter power control system of the present invention uses the pilot signal returned by the space station, so it is possible to control the transmit power with high accuracy, and the control operation is performed using open-loop control. Since the control operation does not become unstable even if the response time is shortened, it has the effect of compensating for rapid fluctuations in rainfall attenuation.

[Brief explanation of the drawing]

Figure 1 shows the earth station transmission power 11tlJll11 of the present invention.
Figures 2 and 3 show an example of the Katana type. j1 Conventional earth station transmission power control - Katana type 1. FIG. 7 is a block diagram showing a second example. 1...Pilot signal generator, 2...
Variable gain amplifier, 3, 8. 12... No pre-amp, Do, 4... A, G converter, 5...
・Power amplifier, 6... Antenna, 7...
・Low noise amplifier, 9.10...Down converter, 11...Bean signal receiver, 13...
... Pilot signal receiver, 14 ... Control signal output circuit. Agent: Susumu Uchihara, patent attorney 7. ,5・”i,-
,.

Claims (1)

[Claims] Pilot signal generation means for generating a pilot signal; level control means for controlling the level of a communication signal based on a control signal; and the communication signal and the pilot signal output by the level control means. a transmitting means for transmitting the communication signal and the pilot signal outputted by the combining means to the space station; and a transmitting means for transmitting the pilot signal transmitted by the transmitting means and returned via the space station. a pilot signal receiving means for receiving a signal and detecting a reception level or a carrier-to-noise power ratio; and a pilot signal receiving means for receiving a beacon signal in a communication frequency band emitted by the space station and detecting a reception level or a carrier-to-noise power ratio. An earth station comprising: a beacon signal receiving means; and a control signal outputting means for outputting the control signal according to a ratio between a detection signal of the beacon signal receiving means and a detection signal of the pilot signal receiving means. Transmission power control method.