An adaptive method for closed-loop transmit multiple antenna diversity

For better performance, various diversity techniques can be utilized in wireless communications. Recently, transmit antenna diversity (TAD) has been employed for 3rd generation (3G) code division multiple access (CDMA) systems. Performance can be greatly improved by using more transmit antennas. In this paper, we present an adaptive method for closed-loop TAD. It is shown that the adaptive method can efficiently increase the number of transmit antennas without significantly increasing the feedback bit rate. In closed-loop TAD, feedback delay and errors can degrade performance. To overcome feedback delay, the use of channel prediction is proposed.