Linear hybrid interference cancellation for DS/CDMA signals

It is well known that direct-sequence code-division multiple-access (DS/CDMA) systems are capacity limited due to multiple access interference from active users. In recent years, several multiuser detectors have been developed to overcome this performance limitation. One such class of detectors includes the successive interference canceler (SIC) and the parallel interference canceler (PIC). The PIC usually operates well in situations where the users have relatively equal powers, whereas the SIC is better suited for users with a range of powers (i.e., near-far conditions). In this paper, we examine a linear hybrid interference canceler (LHIC) which combines the parallel and successive architectures in a weighted manner. This combination is based on an optimized weighting, which we compare to a simple suboptimal approach. A primary advantage of the hybrid detector is its ability to successfully operate for a wide range of signal scenarios when the amplitude profile does not conform to those for which the SIC and PIC detectors separately achieve their best performance.