Adaptive successive interference cancellation for the IS-95 uplink

Abstract

In this paper we examine an adaptive successive interference canceler (ASIC) that can separate direct-sequence code-division-multiple-access (DS/CDMA) signals for the IS-95 (Interim Standard 95) uplink under near-far conditions, i.e., without power control. The ASIC employs a multistage architecture where each stage consists of a conventional matched filter (MF) detector with equal gain combining (EGC), followed by an adaptive interference canceler (AIC) that is adjusted by the least-mean-square (LMS) algorithm to track time-varying multipath channels. Variants of the basic ASIC architecture which exploit the specific structure of the IS-95 uplink traffic channel are also discussed. The bit-error-rate (BER) performance of the ASIC is compared with that of other interference cancelers, demonstrating the effectiveness of the ASIC for near-far scenarios.