Abstract
Direct sequence code division multiple access (DS-CDMA) is an important scheme for the current second generation (2G) Interim Standard (IS-95) and third generation (3G) wireless network. In DS-CDMA uplink channel, the capacity is greatly limited by multiple access interference (MAI), near-far effect, and channel fading effect. To overcome those problems, there have been many power control schemes with multiuser detection and error correcting code reported in the literature. In this thesis, a power control scheme with a space-time iterative multiuser receiver for turbo-coded DS-CDMA systems is proposed. The proposed receiver structure consists of a bank of single-user 2D-RAKE receivers, a space-time turbo partial parallel interference cancellation detector, which is presented by Shih and Wang, and a bank of single-user turbo decoders, where is the number of active users. We exploit the space-time processing to first suppress MAI and then extract reliable soft information from the exchange between multiuser detector and turbo decoders by the way of turbo processing. Based on the synchronous multiuser DS-CDMA model, the computer simulation results are carried out in the single cell environment with path loss, shadowing, and multipath fading. As compared with the same complicated power control method using space-time partial parallel interference cancellation technique, the proposed approach provides better performance.