Fast blind identification of FIR communications channels

This contribution describes a fast frequency domain approach for blind channel identification which does not rely on the statistics of the symbols. The proposed approach is based on the so-called "intraspectral relations" of DFTs of PAM fractionally sampled signals. The use of DFTs is allowed under certain conditions commonly encountered in data communication systems. The intraspectral relations are equivalent to analogous relations introduced in the time domain in Xu et al. (1995), Moulines et al. (1995) and Hua (1996). From the intraspectral relations, asymptotically efficient solutions are derived which turn out to be either more accurate or less expensive in terms of complexity w.r.t. the time domain counterparts. Simulation results are provided to assess the validity of the proposed approach in comparison with the Rao Cramer bound and with other approaches from the literature.