JPH05218924A - Transmission power control system - Google Patents

Abstract

PURPOSE:To improve the accuracy of the transmission power control system used for level control of a rainfall attenuation by controlling the transmission power to different transmission systems with different plural transmission frequencies with a proper control variable respectively. CONSTITUTION:Frequency data 14 of a frequency controller 12 are sent also to a controller 11 through a line for the frequency data 14A and a level control variable corresponding to a frequency signal sent finally is obtained based on the data with an address of up-converters 1, 2 added thereto. That is, a level of a signal received by a beacon receiver is detected at an earth station for satellite communication and the level is compared with a reception level at a fine weather to measure a rainfall attenuation of a reception signal level at rainfall. Then according to a relation formula of a propagation frequency between the rainfall attenuation and the rainfall intensity, the intensity is obtained at first and the rainfall attenuation compensation quantity is calculated by substituting the transmission frequency of up-link to the formula and the result is sent to a level controller as a control signal.

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, and more particularly to a transmission power control method for compensating for uplink rain attenuation in an earth station using a frequency above the quasi-millimeter wave band where rain attenuation is large in satellite communication. ..

[0002]

2. Description of the Related Art Generally, in a satellite communication earth station, when a frequency above the quasi-millimeter wave band with large rain attenuation is used, when the rain attenuation is large, the transmission power of the earth station is increased to increase the uplink rain attenuation. The transmission power control for compensating for is required.

Conventionally, as an operation procedure of this type of transmission power control system, downlink rain attenuation is actually measured using a beacon signal transmitted from a satellite, and the frequency of the beacon signal is used as a parameter from the measured value, which will be described later. First, the rainfall intensity R (mm / h) is obtained from the relational expression (1). Then use this R for the uplink transmit frequency,
Rainfall attenuation A is calculated again using equation (1).

Next, the relational expression (1) is the attenuation amount AdB / Km.
When the rainfall intensity is R (mm / h), the coefficient is r, and the power is n = 0.88 (17.7 GHz ≦ f <31 GHz), A = r · R ⁿ (1) Here, the count r is a function of the frequency and becomes the formula (2).

R = 0.1423-3.0976 × 10 ⁻² × f + 3.1174 × 10 ⁻³ × f ² −8.8328 × 10 ⁻⁵ × f ³ + 8.9270 × 10 ⁻⁷ × f ⁴ ( 2) The transmission power control for compensating the amount of rain attenuation in the uplink is performed using the above equations (1) and (2). As a configuration of such a conventional example, the configuration shown in FIG. 3 is used. ..
In FIG. 3, an input signal A to the transmission system is converted into a transmission frequency by an up converter 1 and level-controlled by a level controller 3 to output an RF signal 3A. The other input signal is converted into a transmission frequency by the up-converter 2 and level-controlled by the level controller 4 to generate the RF signal 4B.
Is output. The RF signals 3A and 4B are combined by the combiner 5 and the two transmission signals of different frequencies are commonly amplified to a predetermined level by the power amplifier 6 and transmitted from the antenna 7. Next, in the receiving system of the earth station, the beacon signal from the satellite is received by the antenna 7, amplified to a predetermined level by the low noise amplifier 8, converted to a predetermined frequency by the down converter 9, and beaconed by the beacon receiver 10. The signal is detected. The controller 11 inputs this beacon signal, compares it with a reference value, and transmits the level controllers 3 and 4 of the transmission system.
Calculate the level control amount to send control information to. Here, the reference value stores the beacon signal level in fine weather.
That is, the level of the difference from the time of fine weather including rain attenuation is calculated. Next, after substituting the rainfall attenuation amount by the beacon signal into the equations (1) and (2) to obtain the rainfall intensity, the attenuation amount A is calculated by the above-described specific transmission frequency, and the control amount data 25 is obtained. It was applied to the level controllers 3 and 4 to correct the amount of rainfall attenuation.

[0006]

In the above-described conventional transmission power control method, when the transmission route is composed of a plurality of routes having different frequencies, the control amount is calculated for a representative transmission frequency and the other transmission frequencies are calculated. Since the same control amount is used for the frequency transmission route, there is a drawback that a rain attenuation compensation error occurs due to the frequency difference.

An object of the present invention is to provide a transmission power control device capable of controlling transmission power with a proper control amount for a plurality of transmission systems having different transmission frequencies.

[0008]

A transmission power control system of the present invention is a satellite communication earth station, in which a received signal level is detected by a beacon receiver and compared with a received signal level in fine weather to receive a received signal in rainfall. Level rain attenuation is measured, and based on this relational expression of rain attenuation, rain intensity and propagation frequency, first the rain intensity is calculated, and then the transmission frequency of the uplink is substituted and the rain attenuation compensation amount of the transmission signal is calculated. In a transmission power control system including a controller for calculating and transmitting a control signal, and a level controller for receiving the control signal and performing level control proportional to the control signal, the controller has a plurality of transmission frequency information. Is input to the plurality of level controllers corresponding to the corresponding transmission frequencies, and a control signal for compensating the individual rainfall attenuation amount obtained by the above relational expression is transmitted.

[0009]

The present invention will be described below with reference to the drawings. FIG. 1 is a block diagram of the first embodiment of the present invention.
1, the same reference numerals as those in the conventional example of FIG. 3 have the same configuration and function. That is, in this embodiment, the frequency controller 1
The frequency data 14 of No. 2 is also transmitted to the controller 11 through the line of frequency data 14A. In the second embodiment described later, the frequency data 14A is used instead of the frequency data 14A.
It is directly transmitted to the level controllers 3 and 4 through the line B.

In the first embodiment, the controller 11 inputs the frequency control data 14 with the addresses of the up-converters 1 and 2 shown in FIG. 2 from the external frequency controller 12, and controls the level corresponding to each frequency. The amount is calculated based on the equation (1) described in the conventional example. Finally, the level control amount corresponding to the transmission frequency is obtained and sent to the level controllers 3 and 4 in the form of the control amount data 13 with the address of the up converter shown in FIG. Level controller 3, 4
When the reception control data 13 matches its own address, the control data is received as control information to control the transmission power. In this way, when there are a plurality of transmission waves having different transmission frequencies, level control matching the transmission frequency is possible even in an operation mode in which the transmission frequency is changed according to the time schedule.

Next, a second embodiment of the present invention will be described with reference to the block diagram of FIG. As described above, it is almost the same as the first embodiment, except for the following points. The controller 21 does not have a function of inputting the frequency control data from the frequency controller 12, and the line of the frequency data 14B (dotted line in the figure) is used in FIG.
As shown in (b), the control data for the specific transmission frequency is data 2 in which no address is added as in the conventional example.
5 is transmitted. Therefore, both level controllers 22 and 23 receive the same data, but as shown in FIG. 2B, the frequency control data 14B with an address is input from the frequency controller 12, and this frequency and the above-mentioned specific frequency are input. From the difference between the two, the control data is corrected in the level controller based on the equation (1), and the transmission power control is performed. In the present embodiment, the case where the level control amount is obtained using the beacon signal level has been described, but it is also possible to obtain the level control using C / N instead of the signal level.

[0012]

As described above, the transmission power control method of the present invention uses the uplink transmission control method based on the rainfall attenuation amount using the beacon signal, but a plurality of transmission waves having different transmission frequencies are used. Since the level control based on the actual transmission frequency is performed even in the operation mode in which the transmission frequency changes according to the time schedule, there is an effect that the accuracy of the level control of the rainfall attenuation amount can be improved for each transmission frequency.

[Brief description of drawings]

FIG. 1 is a block diagram of first and second embodiments of the present invention.

FIG. 2 is an explanatory diagram of respective signals of the first and second embodiments.

FIG. 3 is a block diagram of a conventional transmission power control method.

[Explanation of symbols]

1, 2 up converter 3, 4 level controller 5 combiner 6 power amplifier 7 antenna 8 low noise amplifier 9 down converter 10 beacon receiver 11 controller 12 frequency controller 13 control amount data 14 frequency data 14A, 14B 1st and The frequency data line of the second embodiment.

Claims (2)

[Claims] 1. In a satellite communication earth station, a received signal level is detected by a beacon receiver, and the amount of rainfall attenuation of the received signal level during rainfall is measured by comparing with the received level during fine weather,
Based on this relational expression of rainfall attenuation, rainfall intensity, and propagation frequency, first calculate the rainfall intensity, then substitute the uplink transmission frequency to calculate the rainfall attenuation compensation amount of the transmission signal and send the control signal. In a transmission power control system including a controller and a level controller that receives the control signal and performs level control proportional to the control signal, the controller inputs a plurality of transmission frequency information and each corresponding transmission frequency To a plurality of level controllers corresponding to the above, a control signal for compensating the individual rainfall attenuation amounts obtained by the above relational expression is sent out. 2. The plurality of level controllers directly input transmission frequency information and transmission route information instead of the controller, and based on the relational expression, control for a specific frequency input from the controller. 2. The transmission power control method according to claim 1, wherein the signal is corrected to obtain a control signal of rainfall attenuation corresponding to each transmission frequency.