Adaptive Transmission for Finite-Rate Feedback MIMO Systems

Adaptive transmission which adjusts optimally transmit power level, preceding matrix, modulation and coding schemes at the cost of perfect channel state information (CSI) , can greatly improve the performance of a communication link under fading environment. As the perfect CSI is difficult to be available at transmitter, it is valuable to study the adaptive design with partial CSI. Previous works showed that preceding with limited feedback proves effective in increasing transmission rate in the multiple-input multiple-output (MIMO) systems, and further performance gain can be achieved if power control is used along with quantized preceding. However, adaptive modulation and coding (AMC) has not been considered in previous works with partial CSIT. In order to maximize transmission rate under the constraint of fixed transmit power and target quality-of-service (QoS), we develop a novel adaptive preceding scheme along with joint power and bit loading for finite-rate feedback MIMO systems. What´s more, the preceding matrix and power information are fed back through double codebooks for reducing the feedback overhead. In addition, codebook design for power information is given. Simulation results show that the proposed scheme greatly improves the transmission rate with low feedback overhead.