JPH01170227A - Transmission power control system - Google Patents

Abstract

PURPOSE:To attain high efficiency and less heat in fine weather, to adopt a proper cooling method such as cooling utilizing rain water in rainfall and to reduce the effect even with a large heat by switching the bias state of a trans mission power amplifier depending on the state of weather. CONSTITUTION:The bias state of a transmission power amplifier 5 is subject to switching control in 25 stages depending on the weather. That is, the bias state to stages close to the final stage with a large heat and large power con sumption especially is set different from rain and fine weather, the weather is identified depending whether a signal level of a received beacon signal or a pilot signal is a prescribed value or over, or depending whether a measuring signal of quantity of rain is a prescribed value or over, and then the bias state is switched to the state corresponding to the weather. Thus, the heat in fine weather is suppressed, and the effect at a large heat in rainfall can be suppressed by adopting a proper cooling method (such as forced cooling by rain water).

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a transmission power control method when performing satellite communication, and in particular, the present invention relates to a transmission power control method when performing satellite communication, and in particular, the present invention relates to a transmission power control method when performing satellite communication. The present invention relates to a transmission power control method in which switching control is performed in two stages based on the following.

[Conventional technology]

In wireless communications, especially in satellite communications that use frequencies above micro-congestion, transmission power control is generally used to cope with rain by increasing transmission power in order to ensure the reliability of communication lines even during rainy days. It has been adopted. For example, in the case of Japanese Unexamined Patent Application Publication No. 57-132437, the correlation between the amount of rainfall attenuation of the earth sweep multiplied signal and that of the satellite beacon signal is used to determine the intermediate frequency based on the signal level of the satellite beacon signal received at the earth station. Transmission power at the earth station is controlled by continuously variable control of the transmission signal level at the wave stage.

[Problem that the invention seeks to solve]

According to the above publication, the reliability of the communication line is ensured regardless of the weather conditions by controlling the transmission power at the earth station based on the received beacon signal level, but the transmission power amplifier The efficiency of the process is not good, and the amount of heat generated in the process cannot be ignored. This is because the bias state of the power amplifier is semi-fixed to the output up state during rainy weather.

On the other hand, the transmission power amplifier and its peripheral circuits are usually installed outdoors and are cooled by natural heat radiation, but the increase in heat generated by the power amplifier may lead to an increase in the size of the housing structure.
On the other hand, the rise in temperature within the casing has a negative effect on peripheral circuit components, resulting in problems.

The purpose of the present invention is to develop a transmission power control method that is capable of suppressing the amount of heat generated in the transmission power amplifier except in rainy weather. This is achieved by switching the state into two stages depending on the weather conditions.

[Effect]

The idea is to set the bias state of the transmission power amplifier, especially the stage near the final stage that consumes a large amount of power and generates a large amount of heat, to be different in rainy weather and in sunny weather. The weather condition is identified based on whether the signal level of the received beacon signal or pilot signal is above a certain level, or whether the rainfall measurement signal is above a certain level, and the bias state is set to correspond to the weather condition. We are trying to switch to . As a result, the amount of heat generated in sunny weather is suppressed, and even if the amount of heat generated is large in rainy weather, the effect of this can be suppressed by adopting an appropriate cooling method (for example, forced cooling with rainwater). is possible.

[Example] The present invention will be explained below with reference to FIGS. 1 to 4.

First, before entering into a detailed explanation of the present invention, how the input/output characteristics and transmission power amplifier efficiency change depending on the difference in bias point will be explained as follows.

That is, in satellite communication, digital communication is performed using a class A operating power amplifier, and the bias point according to the present invention is set as shown in FIG. The bias point in rainy weather is set at point A where there is little distortion and the maximum output is obtained, and the human output characteristic a for this point is
is as shown. In addition, the bias point during clear skies is set at point B, since there is no need to compensate for the amount of attenuation due to rain.
As shown in the figure, the input/output characteristic for this is that although the linearity is saturated at a low required power, the efficiency as a power amplifier is better than when the bias point is set at point A.

Now, to explain the present invention in detail with reference to FIGS. 1 to 3, the bias in the transmission power amplifier is determined by the received pilot signal level, received beacon signal level, and rain measurement signal level. 1 shows a schematic configuration of a transmitter/receiver for satellite communication according to the present invention in the case of point switching control.

First, referring to FIG. 1, a transmission signal from a modem 1 passes through an intermediate frequency amplifier 2, and after its signal level is adjusted by a variable level setter (variable attenuator) 3, it is sent to a frequency converter 4. The signal is transmitted from the antenna 7 to the satellite via a transmission power amplifier 51 and a branching filter 6. Further, a transmitted signal from a satellite is received by an antenna 7, and then converted to an intermediate frequency by a frequency converter 9 via a low noise amplifier 8. This intermediate frequency band contains a pilot signal in addition to the desired signal, and the pilot receiver l
At O, the desired signal is subjected to automatic gain control (AGC), automatic frequency control (AFC) depending on the detected pilot signal.
) is applied to the modem 1 via the intermediate frequency amplifier 11.
It is now sent to . The pilot signal is also level-converted to a predetermined value by the transmission power controller 12, and is used as a level setting control signal to control the level of the transmission signal at the variable level setting device 3. The level setting control signal to the level variable setting device 3 is also compared with the reference signal level by the bias controller 13, and based on the comparison result from the bias controller 13, the bias setting device 14 outputs the comparison result. A bias voltage corresponding to is applied to the transmission power amplifier 5. When the level of the pilot signal becomes lower than the reference level due to rain, the bias setting device 14
, a bias voltage that increases the transmission power is applied to the transmission power amplifier 5.

Next, referring to FIG. 2, it is almost the same as in the previous case except that the level control and bias switching control of the transmission signal are performed based on the beacon signal obtained by the beacon frequency converter 15 and the beacon receiver 16. It becomes.

Finally, referring to FIG. 3, the case of FIG. 1 is the same as that of FIG. It is the same. Regardless of which signal bias switching control is performed, if the transmission power amplifier is actively cooled with rainwater, the influence of heat generation can be considerably reduced.

〔Effect of the invention〕

As explained above, in the case of the present invention, the bias state of the transmission power amplifier is switched depending on the weather conditions, so it is highly efficient and requires less heat generation on sunny days, and even on rainy days, it is cooled by rainwater. By adopting an appropriate cooling method such as this, even if the amount of heat generated is large, its effect can be reduced.

[Brief explanation of the drawing]

1, 2, and 3 are diagrams each showing a schematic configuration of a transmitting/receiving device for satellite communication according to the present invention, and FIG. 4 shows the input/output characteristics and amplifier efficiency depending on the bias settings for the power amplifier. FIG. 3 is a diagram for explaining how the change changes. l...Modem, 2,11...Intermediate frequency amplifier, 3.
...Level variable setter, 4.9...Frequency converter, 5
-... Transmission power amplifier, 6... Duplexer, 7... Antenna, 8... Low noise amplifier, 10... Pilot receiver, 12... Transmission power controller, 13... Bias controller, 14... Bias setting device, 15... Beacon frequency converter, 16... Beacon receiver, 17...
・Rain gauge. Agent Patent Attorney Masami Akimoto

Claims (1)

[Claims] 1. A transmission power control method for a transmission power amplifier for satellite communication, which includes the comparison result of the signal level of a received beacon signal, the signal level of a received pilot signal, or the signal level of a rain measurement signal with a reference level. A transmission power control method characterized by controlling the bias state of a transmission power amplifier in two stages based on the following.