Joint identification of merge signals in non-cooperative digital telecommunications

摘要

A real-time method for the separation and blind demodulation of digital telecommunication signals, referred to as channels, from the observation, by means of a single sensor, of a composite signal comprising said signals, the parameters of these channels including the modulation type, amplification, phase shift, delay time at the sensor, frequency and modulation speed thereof, said parameters for the different channels being capable of being different or substantially or perfectly equal, said method comprising the following steps: preprocessing of the sum signal; estimation of the parameters of the channels in terms of the Maximum Likelihood via a suitable EM algorithm, in which the calculation of the conditional expectation of the log-likelihood is carried out recursively by a specific filter-smoothing method; joint demodulation of the channels according to a stochastic Viterbi algorithm; monitoring of the temporal progression of the parameters of each channel.