Energy efficient coordinated beamforming in distributed antenna systems

A coordinated beamforming scheme in distributed antenna systems (DASs) used for energy efficient transmission is developed. In this paper, a dynamic circuit power consumption is considered which varies with the sum rate. The major problem is non-convex of the optimization problem and is difficult to solve directly due to the fractional form. It is transformed into an equivalent subtractive-form optimization problem, by which we tackle this problem through a two-layer optimization algorithm. The out layer problem is solved by using one dimension search method while the inner-layer sub-problem is solved with an optimal beamforming algorithm. The simulations illustrate that the proposed algorithm outperform the weighted minimum mean square error (WMMSE) algorithm.