Antenna Verification for Closed Loop Transmit Diversity

In this paper we discuss the problem of estimating, at the mobile receiver, the weights applied by the Node-B transmitter when closed loop transmit diversity is used. This problem is referred to as antenna verification in the UMTS literature and performance of any closed loop scheme depends greatly on the accuracy of such an estimation. Maximum A Posteriori and Minimum Mean Square Error formulations are sought, and corresponding antenna verification algorithms are derived under the two criteria. The problem of transmit power estimation is also addressed since power estimates are required in the antenna verification algorithms. Optimal power sequence estimation algorithms are derived for power controlled communications. The tradeoffs associated with pilot power allocation in terms of its effects on minimizing the total transmitted power are also discussed.