Multiuser detection with cell diversity for DS/CDMA systems

This paper presents a multiuser detection scheme based on cell diversity for DS/CDMA systems. This scheme may be employed when multiple base stations can receive the signal from a mobile. Each participating base station uses a decorrelator to remove multiple access interference and obtains the decision statistic for each user. It then quantizes the decision statistic and transmits it to a central processor. Based on these received quantized cell decision statistics, the central processor determines the received bit for each user. The quantizer proposed here is a MMSE log likelihood ratio quantizer, and is obtained via a Lloyd-Max type of algorithm. The decision-making rule at the central processor is derived based on multisensor signal detection theory. Numerical results show that significant performance improvement over single cell multiuser detection can be obtained at a moderate cost in terms of additional signal processing and communication bandwidth.