Modem for a PMP radio system using trellis coded modulation with burst transmission

A new family of modems for point-to-multipoint (PMP) systems is described, designed to improve frequency utilisation, power economy and transmission quality. The key technique is the application of the trellis coded modulation (TCM), which gives a coding gain compared to uncoded modulation schemes, thus resulting in higher system gain and/or lower transmit power (RF and DC). However the applicability of the TCM to burst operation, which is needed in such TDMA systems, is not obvious. This contribution describes, how the modem is built up and how digital signal processing lead to a clear, flexible and powerful design