Blind estimation of digital communication channel impulse response

The article propose novel approaches to the problem of blind channel impulse response estimation for data communication systems, including telephone channels as well as digital radio channels. No training sequence is assumed to be available. Two novel schemes are proposed for channel impulse response estimation. Only batch (nonrecursive) methods are considered. The higher order cumulant statistics is exploited, in addition to the usual second-order statistics, of the data and of appropriately defined error signals. The proposed methods yield (globally) optimal solutions. The estimated channel impulse response can be used for channel equalization, either for reliable (“open eye”) initialization of the conventional decision-directed equalizers or as a channel estimator for a Viterbi algorithm based equalizer. Two illustrative examples one for a telephone channel and the other for a multipath channel, are given using an 8-level PAM signal