Efficient blind estimation and equalization of non-minimum phase communication channels via the use of a zero forcing equalizer

Via the use of a zero forcing equalizer, the blind estimation of a finite impulse response (FIR), non-minimum phase (NMP) channel is discussed in this paper. Two efficient and reliable blind estimation algorithms are proposed here. One is based on the combination of second-order statistics (SOS) and the kurtosis property of the transmitted signal. The other utilizes the SOS information and the finite alphabet (FA) knowledge of the transmitted signal. SOS based methods provide efficient estimation of channel zeros from a very small number of samples, but the estimates are phase blind. The kurtosis property and the FA information can be used to resolve the ambiguity in system zero location. It is also shown that the equalizer output could be exploited recursively to improve the estimation accuracy using the FA property. As all the available information are used, the proposed methods achieve a very high accuracy in blind channel estimation. Performance of the estimation methods is also discussed. As the method inherently uses an equalizer, separate equalization is not necessary.