Analytical results for capacity improvements in CDMA

In this paper, we examine the performance enhancements that can be achieved by employing spatial filtering in code division multiple access (CDMA) cellular- radio systems. The goal is to estimate what improvements are possible using narrow-beam adaptive antenna techniques, assuming that adaptive algorithms and the associated hardware to implement these systems can be realized. Simulations and analytical results are presented which demonstrate that steerable directional antennas at the base station can dramatically improve the reverse channel performance of multicell mobile radio systems, and new analytical techniques for characterizing mobile radio systems which employ frequency reuse are described using the wedge-cell geometry of [1]. We also discuss the effects of using directional antennas at the portable unit. Throughout this paper we will use phased arrays and steerable, fixed pattern antennas to approximate the performance of adaptive antennas in multipath-free environments.