CodificaÃÃo iterativa para o canal adtivo com dois usuÃrios binÃrios

AUTOR(ES)
DATA DE PUBLICAÇÃO

2005

RESUMO

This thesis is concerned with an investigation of iterative coding schemes for the two-user binary adder channel (2-BAC). A coding scheme is introduced for the 2-BAC using a single convolutional code which permits efficient decoding. The constructed two-user trellis codes have a significant practical advantage because iterative decoding techniques used in the single-user case, related to Viterbi decoding and to the maximum a posteriori probability rule, apply to the two-user case after minor modifications. A novel coding scheme is presented for the 2-BAC using a two-dimensional block code (product code), also called collaborative coding multiple access, for practical application which uses turbo decoding for improving performance. A new hierarchical coding scheme is introduced, which allows an increase of the overall traffic over existing Ethernet networks, with backward compatibility with existing users. In this scheme new users will be added with the proposed code, while the existing users will be able to continue receiving services without change of hardware. Finally, a condition is introduced for unique decodability over a quasi-synchronous twouser binary adder channel for a class of codes, and simulation results are presented the over a synchronous and a quasi-synchronous two-user binary adder channel in the presence of white Gaussian noise

ASSUNTO(S)

canais de acesso mÃltiplos, cÃdigos turbo, ccma ccma multiple access channel turbo codes engenharia eletrica

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