During the last decade there has been a rapid growth in the provision of high speed and high quality wireless data services. However, in a wireless environment, the transmitted signal suffers extensive noise, inter-symbol interference, fading and shadowing caused by multi-path propagation. Therefore, it is a challenging job to achieve high speed and high quality transmission in such a harsh environment at a reasonable price....[ Read more ]

During the last decade there has been a rapid growth in the provision of high speed and high quality wireless data services. However, in a wireless environment, the transmitted signal suffers extensive noise, inter-symbol interference, fading and shadowing caused by multi-path propagation. Therefore, it is a challenging job to achieve high speed and high quality transmission in such a harsh environment at a reasonable price.

In this thesis, an adaptive hybrid FEC/ARQ scheme using turbo codes combined with ISI mitigation technique is proposed as a novel solution. Turbo codes, a class of parallel concatenated recursive systematic convolutional codes introduced very recently with near Shannon capacity performance, is considered the most important breakthrough in coding since Ungerboeck introduced trellis codes in 1982. The purpose of the research is to analyze this new coding scheme and optimize its performance for wireless packet transmission by designing a retransmission protocol tailor-made to the code, introducing a family of optimum rate compatible punctured turbo (RCPT) codes, and designing the optimum code structure.

The performances, measured in terms of throughput, packet loss rate and transmission delay, for the proposed scheme over the AWGN channel, the Rayleigh flat fading channel and the frequency selective fading channel with high delay spread and multi-tone interference are analyzed and many simulation results are presented. It can be shown that our proposed system achieves a significant improvement and we find that the excellent error correcting capability, the iterative decoding scheme and the soft channel information utilization of turbo codes are especially suitable for adaptive hybrid FEC/ARQ scheme for packet transmissions.