Performance of parallel concatenated interleaved codes in correlated multipath fading channels in a DS-CDMA system

The performance of a turbo code is investigated for high-bit-rate data transmission in a wideband DS-CDMA system. The effect of correlated multipath fading is studied by considering the performance at typical high and low mobile speeds, when the size of the external interleaver is varied. The performance of the turbo code is found to degrade significantly at low mobile speeds, when a small external interleaver is used. Comparison is also made with an equal decoding complexity convolutional code, over which the turbo code provides a distinct coding gain. Hence, turbo codes are found to be attractive for channel coding in WCDMA based mobile radio systems like UMTS.