Multistage Parallel Interference Cancellation Based on Chase Algorithm

A key issue in a multistage parallel interference cancellation (PIC) scheme is to improve the hard decision accuracy after matched filters (MFs). For achieving this purpose, most PIC schemes focus on choosing the suitable weight for each user in each stage but keeping the hard decision values after MFs intact. This paper presents a new PIC scheme that uses Chase algorithm to edit the possible hard decision combinations and selects the one minimizing a cost function as the final hard decision result for performing the interference cancellation. Performance and complexity comparisons are presented among Chase-PIC, normalized least-mean-square adaptive multistage PIC (NLMS-PIC) schemes and their variants. A new PIC scheme using NLMS as the earlier stages and Chase in the later stages is proposed, which can achieve a better performance than multistage NLMS-PIC but with lower complexity