REDUCED COMPLEXITY SEQUENCE DETECTION FOR NONMINIMUM-PHASE INTERSYMBOL INTERFERENCE CHANNELS

Controlled intersymbol interference may be used to design bandwidth ef ficient coded modulation schemes, The performance of the optimum recei ver depends only on the free distance of the code and is independent o f its phase, Large reductions in receiver complexity are obtained by u sing reduced search detection techniques like the M-Algorithm (MA). Ho wever, we show that MA detector performance depends critically on phas e, and is characterized by the partial energy of the encoder or channe l, The minimum phase encoder needs by far the least detector searching , We propose modifications to the receiver, so that the reduced search ran operate on all nonminimum phase channels at this same low complex ity.