Performance analysis of asymmetric 8-PSK TCM codes in band-limited non-linear channel

Trellis coding with asymmetric modulation is able to attain a performance gain over traditional symmetric constellations combined with trellis coding. The performance of such modulation scheme in a linear Gaussian channel and band-limited non-linear channel, particularly that of the 16-state Ungerboeck asymmetric 8-PSK codes, is analysed. Computer simulations together with estimated error bounds are used to depict the performance trends of these 8-PSK codes, and further confirm the performance improvement obtained in linear Gaussian channel, through introducing an appropriate amount of asymmetry into the MPSK signal constellation. Observation is also made on cross-over point taking place, and performance improvement is not achieved at high bit error probability regions. Such observation is also noted for the asymmetric codes in band-limited non-linear channel, through the computer simulated data