An improved Water Filling algorithm over time varying fading channel

A novel power allocation and adaptive modulation algorithm for MIMO systems over time varying fading channel is proposed. Using water-filling theory in space domains, the optimal power allocation and adaptive MQAM by singular values of the channel transfer matrix with average transmit power constraint is obtained. The spectral efficiency is analyzed. The theoretic analysis and simulation results show that the novel algorithm is robust and easy to implement, and the spectral efficiency of the algorithm is greater than that of early-proposed algorithm with total power constraint.