The University of British Columbia

The performance of turbo codes using differentially detected quadrature phase-shift keying (QPSK) signals transmitted over Rayleigh fast-fading channels is investigated. So far in the open technical literature dealing with turbo codes only slow fading has been considered. Our research has shown that the use of a simple differential detector in conjunction with turbo codes can generally outperform convolutional codes in terms of the bit-and block-error rates for fading rates with a BT product up to 0.1. However, to achieve significant performance improvements, large block sizes must be employed, particularly at slower fading rates