Noise Immunity of a Coherent Signal Receiver with Quadrature Amplitude Modulation in the Presence of Relayed Interference

Using statistical radioengineering methods, we analyzed the noise immunity of the receiving of the signals with multiposition quadrature amplitude modulation (M-QAM) in the presence of noise and relayed interference in the radio channel. It is shown that the reception quality of signals with M-QAM is susceptible to the influence of such interference, and this effect increases as the positioning of the signals increases. It is also established that the noise immunity for the reception of M-QAM signals is significantly better against the background of relayed interference than that of similarly positioned M-PSK signals.