Interference cancellation and complexity reduction in multi stage multi-user detection

Multi stage Parallel Interference Cancellation (PIC) technique gives good performance compared to Successive Interference Cancellation (SIC) method, but biased decision statistic and complexity problems are raised due to imperfect estimation of Multiple Access Interference (MAI) as number of stages increases. Partial Parallel Interference Cancellation (PPIC) technique is proposed to cancel the interference partially stage by stage to overcome biased problem. The complexity reduction for PIC detection is based on the convergence nature of interference cancellation which is called the Difference PIC (D-PIC) detection technique. In this paper we combine (PPIC and DPIC) these two techniques and propose a Multi stage multiuser Hybrid or PD-PIC using MMSE detector for performance improvement and complexity reduction compared to conventional PIC detector. The performance is degraded as the number of users’ increases in each technique. Here considering MMSE for first stage instead of matched filter. Keywords— Multi-user detection, MMSE, MAI, SIC, PIC, PPIC, DPIC and PDPIC.