An iterative power allocation scheme for improving energy efficiency in massively dense distributed antenna systems

The massively dense distributed antenna system (md-DAS) with virtual cells (VCs) has drawn increasing interests recently. In this paper, we develop an energy-efficiency-oriented coordinated power allocation (PA) scheme considering the inter-VC interference in a downlink md-DAS. The problem can be formulated as a complicated non-convex fractional programming problem. To make it tractable, we recast the problem into quasi-concave fractional programming sub-problems, by applying successive Taylor expansion. Then we transform these subproblems into the equivalent convex ones in a subtractive-form based on fractional programming method. An iterative energy-efficient coordinated PA algorithm is finally proposed. Simulation results illustrate that the proposed scheme can offer a significant performance improvement over the existing methods.