Improving the performance of linear MMSE detectors in multi-cell DS-CDMA system

In a single-cell DS-CDMA system, linear MMSE detectors has been shown to significantly outperform conventional detectors in terms of spectral efficiency. Furthermore, simulation shows that the spectral efficiency of asynchronous CDMA systems using MMSE detection and random spreading codes can reach four times that of orthogonal CDMA. In the case of universal frequency reuse, however, this is not necessarily true because of the presence of strong inter-cell interference (ICI). This paper analyzes the reason for the superior performance of MMSE detection in single-cell asynchronous CDMA systems and investigates the potential for performance enhancement using MMSE detection in multi-cell environment with sectorization and a higher frequency reuse factor. Our results indicate that, with sectorization and reduced frequency reuse efficiency, using the MMSE detector can still significantly improve the overall system throughput surpassing that of CDMA systems using conventional detection with universal frequency reuse