Performance of turbo detection in a variable rate wireless system using linear block codes and interleaving

Linear block coding with an iterative detecting-decoding process, namely, t urbo detection, is examined for data transmission within the framework of t he HIPERLAN Type 1 standard. By means of simulations, performance is evalua ted in Gaussian and frequency selective Rayleigh fading channels and the tu rbo detection method is shown to offer superior performance when compared t o soft-decision algorithms; although its high potential is restricted by th e predefined standard, which makes use of a single error-correcting BCH(31, 26) code and a block interleaver of depth 16. In order to improve the performance, we devise an alternative variable codi ng system, having the same physical layer as HIPERLAN, but with the additio nal channel coding options of a three error-correcting BCH(31, 16) code, or of a seven error-correcting BCH(31,6) code. Besides having a modular struc ture, which adapts easily to different information rates, this approach all ows the system to work at lower signal-to-noise ratios (SNRs), ensuring use r connectivity under very hostile channel conditions.