Performance enhancement of DS-CDMA system for wireless local loop

In this paper, performance enhancement of wireless local loops (WLL) employing spatial division multiple access (SDMA) with orthogonal CDMA for both forward link and quasi-synchronous reverse link is investigated. The static channel characteristic of WLL allows base station adaptive antenna arrays and subscriber directional antennas to be used effectively. In such an environment, dynamic sectorization is introduced and a simple dynamic spreading code assignment scheme is proposed to assign codes for users in different areas. Simulations results are presented which demonstrate that using orthogonal CDMA/SDMA with the proposed dynamic code assignment scheme shows drastic improvement over using SDMA or orthogonal CDMA alone.