JPH0563622A - Transmission power controller - Google Patents

Abstract

PURPOSE:To compensate a rainfall attenuation changing minutely based on a frequency and a rainfall quantity with high accuracy. CONSTITUTION:A rainfall attenuation ratio (compensation coefficient) between a transmission signal and a reception signal is stored in a coefficient storage section 74 of a transmission power controller 7 corresponding to an attenuation of the reception signal. A reception attenuation detection section 71 detects a reception level based on a pilot signal or a data signal included in the reception signal and compares the level with a respectively level at a fine weather to detect the reception attenuation. An attenuation control section 72 reads the compensation coefficient corresponding to the detected reception attenuation from the coefficient storage section 74, multiplies a compensation coefficient with the reception attenuation to generate a control voltage Vc. A variable attenuator 73 adjusts a level of a transmission signal St in response to the control voltage Vc to control transmission power.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a transmission power controller,
In particular, the present invention relates to a transmission power controller in a transmitter / receiver of a satellite communication earth station that compensates for rain attenuation for transmitted and received signals of different frequencies.

[0002]

2. Description of the Related Art Generally, in satellite communication, a transmission power controller is provided in a transmitter / receiver of an earth station in order to compensate radio wave attenuation due to rainfall and always supply a constant level of radio waves to a communication satellite. FIG. 3 is a block diagram showing an example of a transmitter / receiver of a conventional satellite communication earth station, and a receiving system includes a low noise amplifier 3 for amplifying a signal received via an antenna 1 and a feeder 2 with low noise, and a predetermined noise amplifier. And a frequency converter 4 for converting into a frequency signal Sr. Further, the transmission system includes a frequency converter 5 that converts a signal St of a predetermined frequency into a transmission frequency, a transmission power amplifier 6, and a transmission power controller 8 that adjusts the level of the signal St to control the transmission power. ing.

Here, the transmission power controller 8 includes a reception attenuation amount detecting section 81 for detecting the attenuation amount of the reception signal due to rainfall,
The attenuation control unit 82 that generates the control voltage Vc according to the reception attenuation amount and the variable attenuator 83 that adjusts the level of the signal St according to the control voltage Vc are included. The reception level is detected by the pilot signal or the data signal included in the reception signal, and the amount of attenuation due to rainfall is detected by comparing with the reception level in fine weather. Further, the attenuation controller 82 multiplies the attenuation amount of the reception level by a constant coefficient to generate the control voltage Vc.

The constant coefficient in this case is a coefficient for performing correction due to the difference between the transmission frequency and the reception frequency because the amount of rainfall attenuation depends on the frequency.

[0005]

In the above-described conventional transmission power controller, the amount of attenuation due to rainfall is calculated by comparing with the reception level in fine weather, and the amount of attenuation of this reception level is multiplied by a constant coefficient to obtain the transmission power. Are in control.

However, in general, the amount of rainfall attenuation is affected by the frequency and the amount of rainfall, as shown in FIG. 4, and when the wavelength of the radio wave is sufficiently longer than the diameter of the raindrop, it is almost only absorbed. However, the ratio of scattering attenuation increases as the wavelength becomes shorter. Also, looking at the curves for the frequency bands used in satellite communication, the slope becomes gentler as the amount of rainfall attenuation increases.

As described above, the amount of rainfall attenuation slightly changes depending on the frequency and amount of rainfall. Therefore, even if the amount of attenuation of the reception level is simply multiplied by a constant coefficient to control the transmission power as in the conventional case, the amount of rain is high. There is a problem that it is impossible to control the accuracy.

An object of the present invention is to provide a transmission power controller which can realize highly accurate rain attenuation compensation.

[0009]

The transmission power controller of the present invention stores in advance the ratio of the amount of rainfall attenuation to the transmission signal and the reception signal of different frequencies as a compensation coefficient corresponding to the amount of attenuation of the reception signal. A means for detecting the amount of attenuation of the received signal, and the compensation coefficient corresponding to the amount of received attenuation detected by the detector is read from the storage means and multiplied by the detected amount of received attenuation to generate a control signal. And means for adjusting the level of the transmission signal according to the control signal.

[0010]

The present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram showing an embodiment of the present invention. Except for the transmission power controller 8, it is the same as the transmitting / receiving device of the conventional satellite communication earth station shown in FIG. 3, and the receiving system is
A low noise amplifier 3 for amplifying a signal received via the antenna 1 and the power feeder 2 with low noise, and a signal Sr having a predetermined frequency.
And a frequency converter 4 for converting to. The transmission system also includes a frequency converter 5 that converts the signal St of a predetermined frequency into a transmission frequency, a transmission power amplifier 6, and a transmission power controller 7 that adjusts the level of the signal St to control the transmission power. ing.

Here, the transmission power controller 7 includes a reception attenuation amount detecting section 71 for detecting the attenuation amount of the reception signal due to rainfall,
An attenuation control unit 72 that generates a control voltage Vc according to the reception attenuation amount, a variable attenuator 73 that adjusts the level of the signal St according to the control voltage Vc, and an attenuation amount compensation coefficient according to the attenuation amount of the reception signal are provided. It has a coefficient storage unit 74 for storing.
The reception attenuation amount detection unit 71 detects the reception level from the pilot signal or the data signal included in the reception signal,
The amount of attenuation due to rainfall is detected by comparison with the reception level during fine weather. Further, the attenuation control unit 72 reads the attenuation amount compensation coefficient for the attenuation amount of the reception level from the coefficient storage unit 74, and multiplies the attenuation amount of the reception level by this attenuation amount compensation coefficient to generate the control voltage Vc.

By the way, in FIG. 4, for example, when the transmission frequency is 15 GHz and the reception frequency is 10 GHz, with respect to the change of the rainfall amount of 1.25 to 100 mm / h,
The attenuation ratio of the transmission signal and the reception signal, that is, the attenuation compensation coefficient changes in the range of about 3 to 1.5. Therefore, since the attenuation compensation coefficient for the rainfall attenuation varies as shown by the curve A in FIG. 2, this attenuation compensation coefficient is stored in the coefficient storage unit 82 in advance for each rain attenuation division range. The straight line B in FIG. 2 indicates the constant coefficient used in the past.

If the attenuation amount of the received signal detected by the reception attenuation amount detecting unit 71 is, for example, X1 (db), the attenuation control unit 72 causes the attenuation amount compensating coefficient K1 corresponding to the attenuation amount X1 (db). From the coefficient storage unit 74 and set the transmission power to K
A control voltage Vc that increases 1 × X1 (db) is generated.
Similarly, when the attenuation amount of the received signal is X2 (db), the corresponding attenuation amount compensation coefficient K2 is read from the coefficient storage unit 74, and the control voltage Vc for increasing the power of the transmitted signal by K2 · X2 (db) is generated. To do.

[0015]

As described above, according to the present invention, the ratio of the rainfall attenuation amount to the transmission signal and the reception signal of different frequencies is stored in advance as the attenuation amount compensation coefficient corresponding to the attenuation amount of the received signal. Every time, the attenuation compensation coefficient corresponding to the attenuation of the received signal is read out, the attenuation of the transmitted signal is calculated, and the transmission power is controlled, whereby highly accurate rainfall attenuation compensation can be performed.

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of the present invention.

FIG. 2 is a diagram showing an example of an attenuation compensation coefficient for rainfall attenuation.

FIG. 3 is a block diagram showing an example of a transmission power controller of a conventional satellite communication earth station transceiver device.

FIG. 4 is a diagram showing a relationship between a frequency and a rainfall attenuation amount using rainfall as a parameter.

[Explanation of symbols]

 7 transmission power controller 71 reception attenuation amount detection unit 72 attenuation control unit 73 variable attenuator 74 coefficient storage unit Vc control voltage

Claims (1)

[Claims] 1. A means for preliminarily storing a ratio of rainfall attenuation amounts to a transmission signal and a reception signal having different frequencies as a compensation coefficient in association with the attenuation amount of the reception signal, and means for detecting the attenuation amount of the reception signal. A means for generating a control signal by reading the compensation coefficient corresponding to the reception attenuation detected by the detection means from the storage means and multiplying the detected reception attenuation by the transmission signal according to the control signal. And a means for adjusting the level.