JPH02285821A - Transmission power controller for satellite communication earth station - Google Patents

Abstract

PURPOSE:To obtain sure control accuracy without increasing required transmission power of a slave station or over when a master station or a sub station exceeds a range of transmission power control by allowing a slave station equipment to compare a transmission signal of the master station and a transmission signal of the sub station so as to apply transmission power control. CONSTITUTION:A master station 1 and a sub station 2 being reference earth stations are provided with a control means making the effective equi-direction radiation power of a satellite 4 from a pilot signal in a communication frequency band and communication signals 101, 102 constant independently of the rainfall attenuation. Earth stations being slave stations 31-3m receive a communication signal 101 from the master station or a communication signal 102 from the sub station 2 to control a transmission power controller 25 via a logical device 24 with a signal from a detector 23 detecting the reception level for level calibration signal. That is, the logical device 24 switches the reception frequency of the reference wave receiver 21 for the master station 1 and the sub station 2 at a proper time interval. The system fault is detected from the difference between the reception of the level calibration signal from the master station 1 and the reception of the level calibration signal from the sub station 2 and the transmission power is controlled under the control of the level calibration signals.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a transmission power control device for a satellite communications earth station, and in particular to the effective isotropic radiated power (E, T) of a satellite output.

The present invention relates to a transmission power control device applied to an earth station that performs transmission power control based on a plurality of earth stations that are equipped with a control means for keeping R, P') constant.

[Prior Art] Particularly in satellite communications that use high frequencies such as the sub-millimeter wave band, radio waves are attenuated significantly due to rain, and appropriate countermeasures are required to deal with this.

Appropriate countermeasures for the downlink from the satellite to the earth station include providing the earth station receiving equipment with a margin to compensate for attenuation, or using the site diversity method to eliminate the effects of rainfall. .

On the other hand, apart from using the site diversity method for the uplink from the earth station to the satellite, it is possible to This results in unnecessary consumption of transmission power by that amount, which is extremely disadvantageous from the viewpoint of effective use of satellite transmission power. Therefore, a method of controlling the transmission power from the earth station according to the rain attenuation of the uplink has been considered, and this is generally referred to as an earth station transmission power control method.

In this transmission power control method, at least one specific earth station among a plurality of earth stations maintains the effective isotropic radiation power of pilot signals and communication signals within the communication frequency band on the satellite regardless of rainfall attenuation. It is equipped with control means.

The other earth stations are equipped with means for controlling their own transmission power using pilot signals and communication signals transmitted by the specific earth station.

As mentioned above, the effective isotropic radiated power (E) of the satellite output.

1. An earth station equipped with a control means to keep R, P) constant is used as a main station or a sub-station that can replace this main station, and other earth stations are used to control the effective isotropy of the satellite output output from the main station or sub-stations. A slave station receives a signal with a constant radiated power to control its own transmission power, and the slave station receives a signal with a constant radiated power to control its own transmission power. Controls the station's transmission power.

[Problems to be Solved by the Invention] In the conventional transmission power control system, the effective isotropic radiation power of the satellite output output from either the main station or the sub station is controlled automatically by a constant signal. When attempting to control the transmission power of a station, if there is rain attenuation to the extent that the main station or sub station cannot keep the isotropically radiated power of the satellite output constant, or if a failure occurs in the transmission system equipment, the slave station's The disadvantage is that the transmission power is larger than necessary, which increases the amount of power used by the satellite.

The present invention has been made in view of the above-mentioned conventional circumstances, and an object of the present invention is to provide a transmission power control device for a satellite communication earth station that can achieve reliable transmission power control.

[Means and effects for solving the problem] The transmission power control device for a satellite communication earth station of the present invention has a plurality of transmitting power control devices each transmitting a level calibration signal with a constant isotropic radiated power emitted from a satellite at different frequencies. A satellite communication system that includes a reference earth station and performs communication between multiple earth stations via a satellite while controlling transmission power based on a level calibration signal, and a transmission power control device provided at the earth station is , a reference wave receiving means for receiving a signal for level calibration, a transmitting means capable of transmitting power control for transmitting a communication signal toward a satellite, a detection means for detecting the reception level of the signal for level calibration, and a reference wave receiving means for receiving a signal for level calibration; The present invention is characterized by comprising logic means for switching the receiving frequency of the receiving means and controlling the transmission power by the transmitting means based on a comparison of level calibration signals from different reference earth stations.

Therefore, when controlling the transmission power of the slave earth station, the frequency of the reference wave receiving means is switched to receive the level calibration signals of the reference earth station, which is the main station and the slave station, and these level calibration signals are used. This allows it to be used as data when controlling the transmission power of the own station.

[Example code] Next, the present invention will be explained with reference to the drawings.

FIG. 1 is a system block diagram of one embodiment of the present invention. In the figure, a main station 1 and a sub-station 2, which serve as reference earth stations, are equipped with pilot signals within the communication frequency band, communication signals 101,
It is equipped with a control means for keeping the effective isotropically radiated power in the 102 satellites 4 constant regardless of rain attenuation. Follow station 31~
The 3m earth station receives the communication signal 101 from the main station or the communication signal 102 from the substation 2, and uses this signal as a reference wave (level calibration signal) to control the transmission power of its own station. We are prepared.

FIG. 2 is a block diagram of an embodiment of the slave station of the present invention.

In the figure, the receiving system includes a transmitting/receiving antenna 11, a low noise amplifier 17 connected to the transmitting/receiving antenna 11,
A receiving frequency converter 18 that converts the output of this low noise amplifier 17 to a required frequency, an intermediate frequency amplifier 19 that amplifies the output of this receiving frequency converter 18 and performs automatic gain control (AGC), and this intermediate frequency amplifier A divider 20 is connected to the output terminal of the divider 20 and detects a level calibration signal to output an automatic gain control (AGC) signal and a transmission power control (TPC) signal. The standard for outputting signals includes a receiver 21 and a group of receiving channel units 221 to 22n connected to the distributor 20 and receiving and demodulating communication signals from a partner station.

On the other hand, the transmission system includes transmission channel units a121 to 12n that modulate transmission signals and generate intermediate frequency signals corresponding to each channel frequency, and a transmission channel unit group 1 of these transmission channel units a121 to 12n.
A combiner 13 that combines the power of each output of 21 to 12n, a transmitting intermediate frequency amplifier 14 whose gain is controlled by a control signal using the output of the combiner 13, and an intermediate frequency amplifier amplified by the intermediate frequency amplifier 14. It includes a transmission frequency converter 15 that converts a frequency signal into a high frequency signal for transmission, and a transmission power amplifier 16 that amplifies the output of the transmission frequency converter 15 to the necessary transmission power and supplies it to the antenna 11 for transmission and reception. These transmitting and receiving systems constitute the earth station's main transmission path.

Furthermore, the earth station is equipped with a transmission power control system, which includes a detector 23 that detects the output level or carrier-to-noise power ratio of the reference wave receiver 21, and a frequency control signal that controls the reference wave receiver 21. to receive a level calibration signal of a different frequency from the main station or sub station, which is taken in as an output signal from the detector 23, and a logic device 24 which controls the transmission power controller 25, and whose output is sent to the intermediate station. It is constituted by a transmission power (TPC) controller 25 for controlling transmission power, which performs signal processing so as to be suitable as a control signal for the frequency amplifier 14.

Next, the operation of this embodiment will be explained. The control mode of the transmission power control method of the satellite communication earth station in this embodiment is normally performed in the estimation mode. A level calibration signal from the main station 1 is received by a reference wave receiver 21, and a transmission power controller 25 is controlled via a logic unit 24 by a signal from a detector 23 that detects the received level of the level calibration signal.

That is, as an operation, estimation control is performed to control the transmission gain from the information of the received signal. However, in this case, the rain attenuation becomes so large that the main station 1 cannot keep the isotropically radiated power of the satellite output constant, or a failure occurs in the transmitting system of the main station's equipment or the receiving system of the slave station's equipment, and the reference signal is When the human power level of the receiver 21 decreases, there is a risk that the transmission power controller 25 will maximize the transmission output level of the slave station.

Therefore, the logic unit 24 selects the reference wave receiver 2 at appropriate time intervals.
Switch the receiving frequency of 1 to main station 1 and sub station 2. Main station 1
Since the level calibration signal output by the sub-station 2 and the satellite output is constant, the level fluctuation of the reference wave receiver 210 normally occurs when the signal from the sub-station 2 is received even when the signal from the main station 1 is received. The same is true at times. However, if the isotropic radiation power of the satellite output cannot be kept constant or a failure occurs in the transmission system of main station 1 or sub station 2, the level calibration signal from main station 1 and the sub station Since there is a difference between when the level calibration signal from 2 is received, it is possible to detect an abnormality in the system. Therefore, by controlling the transmission power based on the comparison of these level calibration signals, it is possible to prevent the transmission output level from becoming higher than necessary.

Note that the frequency switching of the reference wave receiver is determined within a range that does not affect communication and in light of the performance of the device.

[Effects of the Invention] As explained above, according to the present invention, the slave station device performs transmission power control by comparing the transmission signal of the master station and the transmission signal of the subsidiary station. When the transmission power is beyond the range in which transmission power can be controlled, a reliable control system can be obtained without increasing the transmission power of the slave station more than necessary, so the practical effect is extremely large.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing a system configuration according to an embodiment of the present invention, and FIG. 2 is a block diagram showing the configuration of a slave station device according to an embodiment of the present invention. 1...Main station, 2...Sub station, 31~3m...Slave station, 4...Red...Satellite, 11... ...Antenna for transmitting and receiving, 121-12n
...Transmission channel unit group, 13...Synthesizer, 14...Intermediate frequency amplifier, 15...Transmission frequency converter, 16...
...Transmission power amplifier, 17...Low noise amplifier, 18...Reception frequency converter, 19...
...Intermediate frequency amplifier, 20...Distributor, 21...Reference wave receiver, 221-22n...Receiving channel unit group, 23...
...Detector, 24...Logic unit, 25...Transmission power controller, 101...Reference wave output by the main station, 102.
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Claims (1)

[Claims] Equipped with multiple reference earth stations that transmit level calibration signals with constant isotropic radiation power emitted from the satellite at different frequencies, and transmits power between multiple earth stations while controlling transmission power based on the level calibration signals. This is a satellite communication system that performs communication via a satellite, and the transmission power control device provided at the earth station includes a reference wave receiving means that receives a level calibration signal, and a transmitter that sends a communication signal toward the satellite. A transmitting means capable of power control, a detecting means for detecting the reception level of the level calibration signal, and a transmitting means for switching the reception frequency of the reference wave receiving means and comparing the level calibration signals from different reference earth stations. 1. A transmission power control device for a satellite communication earth station, characterized in that it has a logical means for performing transmission power control according to the method.