Bandwidth-efficient correlative trellis-coded modulation schemes

A novel digital modulation scheme is proposed that uses coding to reduce the bandwidth of a signal. The schematic diagram of the transmitter is presented, and optimisation criteria are given and applied to the transmitter. The resulting new modulation schemes are described and compared with traditional schemes. Compared to uncoded M-ary quadrature amplitude modulation, the new modulation schemes allow an increase in the data rate by up to 0.5 bit/s/Hz for a given performance, or to reduce the signal power by about 1 dB for a given data rate