On combined ring convolutional coded quantisation and CPM for joint source/channel coding

Artikel i vetenskaplig tidskrift, 2008

A new trellis-based coded quantisation scheme using ring convolutional codes is presented. When it is combined with trellis-coded continuous phase modulation (TCCPM) with convolutional codes over rings, a powerful joint source and channel coding (JSCC) scheme can be formed. We investigate the additive white Gaussian noise (AWGN) channel and the Rayleigh fading channel. Optimal soft decoding for the proposed JSCC scheme is studied. The soft decoder is based on the a posteriori probability (APP) algorithm for TCCPM with ring convolutional codes. It is shown that these systems with soft decoding outperform the same systems with hard decoding especially when the systems operate at low to medium signal-to-noise ratio (SNR). It is demonstrated that the new trellis quantisation schemes based on ring convolutional codes is superior to conventional trellis-coded quantisation (TCQ) of the same complexity. The novelty of this work is in the development of a trellis-based quantisation method using ring convolutional codes and the use of a soft decoder and the APP algorithm for the combined systems.