Joint Source and Channel Coding using Punctured Ring Convolutional Coded CPM

Artikel i vetenskaplig tidskrift, 2008

In this paper, a novel trellis source encoding scheme based on punctured ring convolutional codes is presented. Joint Source and Channel Coding (JSCC) using trellis coded Continuous Phase Modulation (CPM) with punctured convolutional codes over rings is investigated. The channels considered are 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 trellis coded CPM with punctured 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). Furthermore, adaptive JSCC approaches based on the proposed source coding scheme are investigated. Compared with JSCC schemes with fixed source coding rates, the proposed adaptive approaches can achieve much better performance in the high SNR region. The novelties of this work are the development of a trellis source encoding method based on punctured ring convolutional codes, the use of a soft decoder, the APP algorithm for the combined systems and the adaptive approaches to the JSCC problem.