A comparison of base station transmit diversity methods for third generation cellular standards

Code division multiple access (CDMA) is a common access scheme among all major proposals for third generation cellular standards. The objective of this paper is to show the performance benefits of open loop (which do not adapt transmission based on the channel to the mobile) and closed loop (which do adapt based on the channel to the mobile) transmit diversity methods for CDMA. We examine orthogonal transmit diversity (OTD) (an open loop method), and transmit adaptive arrays (TXAA) (a closed loop method).