Automatic transmit power level control in radio links

Claim 1

1) A transmit power control system in multiline radio links, using microwave signal digital modulation, and specifically so-called multilevel QAM modulation, the said control is used in multiline radio link systems and specifically in each RF transmitter that receives from the respective receiver associated therewith and the interfering receivers, signals indicating the levels of the useful signals received on that RF channel and sends them back to the said associated transmitter in order to regulate the said transmit power level, characterized by the fact that it is comprised of: - means to derive a first control signal for each RF channel in each receiver, and a second control signal for the adjacent channels, - means to combine tha said 1st and 2nd control signals to derive threshold signals, - means to multiplex all of the threshold signals of the individual receivers, - means to insert a station identification signal in the said multiplexer, - means to further multiplex the the said multiplexed signal with other service signals, - means to insert this dual multiplexed signal in the frame of the main information signal transmitted in the other direction of transmission, - means to receive and demultiplex the received signal two times, - means to process this demultiplexed signal so as to derive, on one hand, a transmit power remote control signal, called signal Nr. 1 , protected from possible faults or malfunctions in the main digital channel and, on the other hand, the station identification signal, - means to evaluate exceptional atmospheric precipitation conditions (rain, snow, hail, etc.) through a statistical control of the bit error rate made on the receivers installed in the same station as the transmitters, the transmit power of which is controlled, - means to sumultaneously derive a transmit power local control signal, called signal Nr. 2, in the same station where are installed the receivers, the bit error rate information of which is processed, - means to apply the said control signals to the pre-distor­ tion circuits that are part of the power amplifiers of the transmitters.