Distributed power control for OFDMA based spatial multiplexing multi-hop systems

In this paper, a distributed power control algorithm is proposed to perform adaptive spatial multiplexing for the relay enhanced orthogonal frequency division multiple access (OFDMA) cellular systems. As the optimal spatial multiplexing problem is non-convex, we utilize the distributed iteration method to achieve its near-optimal solution. By determining the restriction on the transmit power for each subcarrier, the individual power allocation at the base station (BS) and the relay station (RS) can always converge to some desirable Nash Equilibriums with satisfying performance. Simulation results show that the proposed distributed power control algorithm provides significant gain in system transmit rate over the traditional iterative water-filling scheme.