An Adaptive QAM Modulation System with STBC Precoding and Covariance Feedback
A low-complexity adaptive quadrature amplitude modulation(QAM) scheme was presented to increase throughput for multi-antenna communication system with covariance feedback.The optimal STBC precoding was achieved according to the criteria of minimizing average bit error rate(BER).An adaptive constellation levels were selected for different channel states to increase throughput under the constraint of the system's BER.The results show good performance,low realization complexity and low feedback overhead.