Decision-feedback equalization and identification of linear channels using blind algorithms of the Bussgang type

We consider the problem of blind equalization of linear communication channels. Some results indicate that the performance of Bussgang blind equalization algorithms can be improved by using diversity such as fractional spacing or antenna array reception. We examine the performance of such algorithms (especially of the popular CMA 2-2), when used in a decision-feedback setup. It turns out that such a simple structure may help in avoiding the common problems of "zeros on the unit circle" (symbol-rate case) and of "zeros in common" (fractionally-spaced case). Theoretical analysis as well as computer simulations are provided in order to demonstrate this fact.