Optimization of sector orientation in CDMA communication architectures based on soft handoff

Soft handoffs are an important part of code division multiple access (CDMA) systems. With the increasing interest in smart antenna away systems, the issue of soft handoff needs to be addressed for CDMA systems with smart antenna arrays. This paper presents an analysis of smart antenna coverage and soft handoffs in a CDMA system. Forward and reverse link capacity are addressed for the smart antenna array system. It is shown that a smart antenna array CDMA system is a forward link limited system. This paper also shows the relevance of soft handoffs on the forward link capacity. With appropriate cell sector orientation, the soft handoff region coverage can be optimized while maintaining an appropriate margin. This will then optimize the soft handoff region size and the overall system capacity. Three architectures are analyzed. It is shown that optimum cell sector orientation with smart antennas closely approximates the interleaved narrow beam tri-sector cell (INBTC) architecture