Optimised MLSE equaliser for fast channel tracking and reliable decoding when using space time DPSK block codes for future WPAN

Communication systems which work in excess of, but close to, the channel´s coherent bandwidth are expected to have a small number of significant components in their channel´s impulse response which causes inter-symbol interference (ISI). Also, for a packet based system, if the channel presents variations during packet transmission, the system can be driven to a high error floor reducing data throughput. The proposed solution uses an optimised maximum likelihood sequence estimator (MLSE) equaliser in conjunction with a space-time block code (STBC) multiple antenna system that works under all the mentioned factors without a considerable increase in complexity but with a high level of flexibility. The optimised MLSE equaliser showed a considerable increment in data throughput for the system under test when using the differential phase shift keying modulation schemes π/2 DBPSK, π/4 DQPSK and 8-DPSK. It is proposed that this approach be adopted for short range, ad hoc, wireless personal area networks (WPAN).