Adaptive linear equalization combined with noncoherent detection for MDPSK signals

A novel noncoherent receiver for M{ary di erential phase shift{keying (MDPSK) signals transmitted over intersymbol interference (ISI) channels is presented. The noncoherent receiver consists of a linear equalizer and a decision{feedback di erential detector. A signi cant performance gain over a previously proposed noncoherent receiver can be observed. For an in nite number of feedback symbols, the optimum equalizer coeÆcients can be calculated analytically and the performance of the proposed receiver approaches that of a coherent linear minimum mean{squared error (MMSE) equalizer. Moreover, a modi ed least{mean{ square (LMS) and a modi ed recursive least{squares (RLS) algorithm for adaptation of the equalizer coeÆcients are discussed.