A Hybrid Serial-Parallel Interference Cancellation Scheme for WCDMA Systems

This paper proposes a hybrid interference cancellation scheme for wideband code division multiple access (WCDMA) uplink transmission. Principles of serial (SIC) and parallel (PIC) interference cancellation are combined with a novel user configuration algorithm (termed "trickle") in order to provide improved bit-error-rate (BER) performance while maintaining overall processing delay as compared to previous hybrid schemes. The proposed scheme utilizes an adaptive matrix to compute the required number of interference cancellation iterations for each user prior to the detection process. The total number of iterations is determined based on the number of users and is set to match that of previously designed interference cancellation models. Bit-streaming, pipelined multiuser detection is employed and channel estimates are obtained using sample pilot data known at the receiver. The trickle algorithm is applied to conventional SIC as well as previous hybrid models. Results show an improvement of 1 dB over group-wise SIC and similar performance to hybrid IC with reduced processing delay at the cost of complexity.