BLIND CHANNEL IDENTIFICATION BASED ON 2ND-ORDER STATISTICS - A FREQUENCY-DOMAIN APPROACH

In this communication, necessary and sufficient conditions are present ed for the unique blind identification of possibly nonminimum phase ch annels driven by cyclostationary processes. Using a frequency-domain f ormulation, it is first shown that a channel can be identified by the second-order statistics of the observation if and only if the channel transfer function does not have special uniformly spaced zeros. This c ondition leads to several necessary and sufficient conditions on the o bservation spectra and the channel impulse response. Based on the freq uency-domain formulation, a new identification algorithm is proposed.