Soft handoffs in code division multiple access systems with smart antenna arrays

摘要

Soft handoffs are an important feature of code division multiple access (CDMA) cellular and PCS systems. With the increasing interest in smart antenna arrays because of their potential for improving the cellular system capacity, the question of how these arrays affect soft handoff arises. This paper presents an analysis of the affect of smart antenna coverage on soft handoffs in a CDMA system in terms of forward and reverse link capacity. It is shown that, with a smart antenna array system, a CDMA system will be a forward link limited system. This paper also shows a method for quantifying the dependence of the forward link capacity on soft handoffs. With appropriate cell sector orientation, the soft handoff region coverage can be optimized while maintaining an appropriate margin, resulting in an improvement in overall system capacity.