Power allocation for energy efficiency maximization in distributed MIMO system over Rayleigh channels

In this paper, we investigate the energy efficiency and power allocation problem for distributed MIMO system over composite Rayleigh channels. Given the maximum transmit power limitation per distributed antenna (DA) port, an adaptive power allocation scheme is developed to maximize the energy efficiency, and corresponding constrained optimization problem is firstly formulated. Because of the non-convex nature of the problem, we transform the constrained optimization problem into a standard convex optimization problem through the fractional programming theory. Then, the optimal solution is derived for the optimized problem by means of the Newton method. To avoid the iteration from the Newton method, another optimal solution is also derived based on Cardan formula. Simulation results show that the proposed scheme is valid, and the scheme with Cardan formula can obtain the same energy efficiency as that with Newton method, but it has lower complexity than the latter.