Channel coding for non-AWGN environments

The reliable transmission of information constitutes the fundamental problem of communication theory. An important component of achieving this goal is use of appropriate channel coding which constitutes the broad subject of this work. The problem of channel coding for non-AWGN environments is addressed; specifically, the code design problems for flat fading and impulse noise channels is investigated for which reliable statistical characterization is available. The work in this dissertation is conceptually divided into three parts. Part I is centered around a novel technique for designing trellis coded modulation (TCM) schemes to counteract simultaneous flat fading and additive white Gaussian noise (AWGN). Part II focuses on the development of a new algorithm for soft-decision decoding of block codes and its performance evaluation over the flat fading channel. In the part III the problem of channel coding for impulsive noise environment is addressed. The primary original contributions of this thesis are (i) the development of a new algorithm that transforms trellis codes designed for AWGN channel into codes that achieve significant gains over flat fading channel, while preserving their coding gain over AWGN channel; (ii) the development of a new technique for soft decision decoding of block codes using the M-algorithm based on a systematic, tree representation of block codes; (iii) the computation of the pairwise error probability as a function of M and the code minimum distance $d\sb{H}$ to arrive at code design principles, as well as a detailed analysis of computational complexity of the algorithm; (iv) the development of code design principles for impulse noise environment, i.e., the choice of a suitable metric (measure of distance between codewords) and the main code design parameters. For each problem, certain questions of practical importance were addressed, and a catalog of simulation results was presented to substantiate the effectiveness of the techniques developed