Tracking the POL-MUX channel by a particle filter

In order to cancel the interference arising between the two signals transmitted over the horizontal and the vertical polarizations of the electrical field in pol-mux transmission, the coefficients of the channel matrix must be estimated. However, when the coefficients are fast time-varying, to estimate or, better, to track them becomes challenging, especially if the estimation is non-data-aided. This paper shows that a non-data-aided particle filter can be used to track the time-varying coefficients. Also, in the paper the weights and the states of the particles are used in a forward-backward scheme in order to demodulate the signal and get the probability distribution of the transmitted modulation symbols. Computer simulations are presented for validating the proposed method.