Efficient Transmit Power Allocation with Partial Feedback for Closed-Loop SQRD Based V-BLAST Systems

This letter proposes an efficient transmit power allocation using partial channel information feedback for the closed-loop sorted QR decomposition (SQRD) based V-BLAST systems. For the feedback information, the positive real-valued diagonal elements of R are forwarded to the transmitter. With the proposed transmit power allocation that is numerically derived by the Lagrange optimization method, the bit error rate performance of the system can be remarkably improved compare to the conventional open-loop SQRD based V-BLAST systems without increasing the receiver complexity. key words: MIMO, V-BLAST, closed-loop system, transmit power allocation, sorted QR decomposition