Linear MMSE interference suppression in asynchronous random-CDMA

This paper considers interference suppression, based on linear minimum mean square error (MMSE) filtering, in random code-division multiple-access (random-CDMA) systems such as IS-95 and wideband-CDMA using long pseudo-noise (PN) sequences. It examines the design of the MMSE receiver and its performance in terms of probability of bit error (P/sub e/). Expressions for P/sub e/ are derived for systems with multiple bit rates (and spreading factors), variable signal powers and chip pulse shaping. Numerical examples show substantial P/sub e/ gains in systems with one to two high-powered users and square-root raised cosine (Sqrt-RC) pulse shaping with 100% excess bandwidth.