Performance Analysis of Switching Multiuser Detector for CDMA Systems

摘要

Multiuser detection is an essential part of Code Division Multiple Access (CDMA) receivers to be able to exploit the bandwidth efficiency, i.e., to support as many users as possible. The major limiting factors considered in CDMA systems with conventional receiver are 1) the need for strict power control to compensate near-far effect and 2) the limit in capacity due to multiple access interference (MAI). Compared to conventional matched filter (MF) receiver, optimal multiuser receiver offers increase both in performance and in near-far resistance in fading channels. However, its computational complexity grows exponentially with the number of users and number of tracked paths. This has lead to the search for sub-optimal solutions, which would offer a trade-off between implementation complexity and performance. In this paper we propose a Switching Successive Interference Canceller (SSIC) which dynamically switches between SIC and matched filter operations depending upon the channel characteristics. The switching detector that we have proposed reduce the overall computational complexity while maintaining a better performance than that of the matched filter and SIC, which helps in practical implementation of the CDMA receiver. The switching criterion is based on the channel characteristics. Future extensions to our work are also proposed.