Space-time diversity multistage parallel interference cancellation (MPIC) for CDMA

Abstract

The paper proposes to enhance CDMA MPIC by using spatial diversity to increase the signal-to-interference ratio (SIR), resulting in a lower BER on every cancellation stage, through utilization of multiple antennas. The paper derives, for the proposed space-time MPIC (SPDMPIC), the recursive equations for both SIR and BER of each cancellation stage and their closed-form expressions as a function of space-time diversity order, the number of needed iterations, and initial SIR condition. It is found that there is an M ( of antennas) times reduction in the available time diversity order for MPIC in achieving the same BER and SIR with STDMPIC of M antennas, as expected, since basically the M antennas provide M times as many uncorrelated multi-paths. The paper also presents simulation results, which agree with the theoretical analysis.