Practical Multiuser Detection Algorithms for CDMA

The aim of this thesis is to investigate practical multiuser demodulation algorithms for mobile communications systems that are based on code division multiple access ( C D M A ) technologies. These include the adaptive receiver and the interference canceller. The overall complexity of implementing them is examined. The effects of the proposed algorithms on reducing of multiple access interference (MAI) and their resistance to the Near Far Effect (NFE) will be explored. Significant work was performed in the investigation of the effect of time offset errors on the partial parallel interference canceller (PIC). The performance of it is compared against that of the standard PIC. The bit error rate (BER) performances of the standard and partial interference cancellers are simulated in a near far environment with varying time offset errors. These simulations indicate that whilst timing errors significantly affect the performance of both these schemes, they do not diminish the gains that are realised by the partial PIC over that of the standard PIC.