Capacity Improvement through Signature Displacement in CDMA Systems

Abstract

Abstract-We evaluate the potential increase in critical load with interference cancellation and (downlink) user capacity by intentionally displacing the signatures of a CDMA system with respect to each other. It turns out that a huge capacity increase, both in terms of user capacity and critical load, is achievable as compared to conventional CDMA systems where all signatures are aligned in time. In addition, we introduce new achievable user capacity bounds that can serve as benchmarks for the evaluation of CDMA systems.