Performance analysis of a 2-stage groupwise successive interference cancellation scheme with groupwise power disparities in DS/CDMA systems

We propose a 2-stage GSIC scheme considering a strict delay constraint and analyze its BER performance in single and multi-cell DS/CDMA systems. Groupwise power disparity is applied in order to enhance the BER performance. We compare the BER performance, complexity and delay of the proposed 2-stage GSIC scheme with those of both conventional detection scheme and SIC scheme. Analysis results show that the capacity increase obtained by both 2-stage GSIC scheme and SIC scheme is smaller in a multicell model than in a single cell model. BER performance enhancement by the proposed 2-stage GSIC scheme is appropriate regarding the minimal increase in cancellation delay and computational complexity. For example, in a multicell DS/CDMA system, the proposed 2-stage GSIC scheme can enhance the user capacity about 21% at BER=10^-2 with twice the cancellation delay and complexity compared with the conventional detection scheme, while the pure SIC scheme can enhance the user capacity 33% with K and K² times increase in delay and complexity, respectively, where K is the number of concurrent users