Performance of a turbo coded multicarrier DS/CDMA system withnonuniform repetition coding

摘要

This paper presents a turbo coded multicarrier direct sequencencode division multiple access (DS/CDMA) system, where the outputs of anturbo encoder are repetition coded at multiple rates and transmitted innparallel over a number of subchannels. A performance bound useful in thenso-called error floor region is obtained for Rayleigh fading channelsnwhen different diversity orders are given to each turbo code symbol.nSimulation results are also provided for the low signal-to-noise ration(SNR) region where the bound is not applicable. It is observed that thenerror floor can be lowered, with some performance loss in the low SNRnregion, by applying nonuniform repetition coding to the turbo codensymbols