A computing method of the error probability in 4PSK transmitting systems under selective fading condition

A method for computing the error probability in 4PSK systems which is easier to implement and shorter to compute than the Gram-Charlier series expansion previously proposed, is described. The method is applicable when the interference amplitude after each pulse vanishes in a time interval shorter than 10 pulse to pulse periods. Models for the complex demodulated signal and for the transfer function of the multipath transmission are presented. A step by step calculation procedure is described and the implementation of the algorithm is discussed. An application example shows that the probability is computed with a 2% precision in one tenth of the time required for the Gram-Chartier series to start convergence.