Reverse link capacity of SIR‐based power‐controlled CDMA systems with antenna arrays
Jin Yu, Yudong Yao · Wireless Communications and Mobile Computing · 2003
Abstract In this paper, reverse link capacity, in terms of user capacity, of a code‐division multiple access (CDMA) system with both beamforming and antenna diversity under a multipath environment is analyzed and compared. Signal‐to‐interference ratio (SIR) based power control is assumed in the system. Antenna elements are divided into several groups to achieve antenna diversity gain. Antenna elements in a group are closely spaced to perform beamforming in order to suppress the own‐cell and other‐cell interference, while those groups are widely spaced to achieve the diversity gain. Based on the comparison, a most efficient use of the antenna array according to the distribution of antenna elements among the groups is obtained. Instead of using tedious iterative methods to evaluate user capacity, a simple closed‐form capacity expression with respect to antenna diversity and beamforming gains, a target SIR and the CDMA processing gain is derived. Numerical results indicate significant capacity improvement with the antenna array. Copyright © 2003 John Wiley & Sons, Ltd.