Blind Channels Responses Estimation by Constrained Clustering

In this paper we consider a receiver with a single antenna which receives at the same time and in the same frequency band, signals from two independent sources. We try to estimate the two propagation channels responses linking the sources to the receiver, without any reference signal, based only on the received signal. We place ourselves in a context of OFDM transmission on a sub-carrier. The sources are not time synchronised but it is assumed that the OFDM symbols transmitted from the two sources are not out of synchronisation by more than the cyclic prefix duration of the OFDM waveform. It is proposed to conduct the estimation of the two channels responses using a constrained clustering algorithm. The estimation performance shows the efficiency of this approach compared to other existing solutions.