Interference cancellation with an array processing MLSE receiver

Capacity and transmission quality in cellular systems can be improved by us ing receivers that mitigate cochannel interference and multipath propagatio n, In this paper, a class of multichannel maximum likelihood sequence estim ation (MLSE) receivers is developed for this purpose. Interference mitigati on is accomplished via adaptive antenna arrays,while multipath propagation is combatted via MLSE. Practical considerations are included, such as fixed front-end filtering, sampling, and estimation of parameters from received samples. Maximal ratio combining, conventional array processing and metric combining (MC) are shown to be special cases of the proposed receivers. Per formance is evaluated for pi/4-shift DQPSK, using the parameters and transm ission format of the time-division multiple-access (TDMA)-based IS-136 (D-A MPS) digital cellular standard, Semianalytical performance predictions are developed which confirm simulation trends. The results show that these rece ivers can operate at significantly lower carrier-to-interferer (C/I) levels than conventional MC receivers.