Trellis-coded 16-QAM with overlapped signal sets for satellite communication systems

A coding technique which achieves, up to a frequency utilization efficiency of 2.6 b/s/Hz, better bit error rate performances than conventional 16-quadrature amplitude modulation (QAM) and 8-phase shift keying (PSK) in nonlinear channels and adjacent channel interferences (ACI) environment is presented. The proposed scheme, 16-OSTQAM, is based on trellis-coding techniques, but employs overlapped signal sets to compensate for the distortion and the increased required power of the 16-QAM signal. Computer simulation is carried out to clarify the performances of 16-OSTQAM compared with those of conventional 16-QAM and 8-PSK, on the same bandwidth efficiency basis and for the same amounts of nonlinearities and interferences. The proposed scheme achieves 6 dB improvement in Eb/No up to 2.6 b/s/Hz, compared with 16-QAM, and more than 6 dB, over 2.52 b/s/Hz, compared with 8-PSK