Optimal Sum Rate of the MIMO Relay Communication System

For a class of the important problems that seek to maximize the sum rate of the multiple input multiple output relay communication system (MIMO RCS) and compute the optimal transmission distributions, we present their mathematical models, and then develop an efficient algorithm for solving this class of the problems. The fixed point theory is used to prove convergence of the proposed algorithm. The performance result of the proposed new algorithm indicates that the proposed algorithm overcomes some limitations of other algorithms. First it utilizes the machinery of parallel computation, a limitation of the previously known iterative water-filling algorithms. Second it is robust to the large number of users $K$, as the previously known iterative water-filling algorithms are not. Not only does the proposed algorithm sufficiently utilize the machinery of parallel computation, but it also shows a strong robustness for the number of the users $K$. At the same time, the proposed algorithm shows fast convergence.