On the radio interface of future ACDMA systems

The authors are investigated trellis coded modulation (TCM) as a candidate modulation scheme for use in a future universal mobile telecommunications system (UMTS) system. To this end, a transceiver architecture is proposed which incorporates TCM, and which would meet the likely relay constraints of the services to be supported by such a future system. A reduced complexity near-maximum likelihood sequence estimator is required to perform combined equalization and decoding of the TCM sequence. This combined equalizer/decoder is presented together with simulation results for its performance. In addition a technique is described which is shown to significantly improve its performance, at the expense of some increase in complexity.<>