Energy Efficient Coordinated Multicell Power Allocation in Dynamic TDD MIMO Systems

In this paper, we investigate coordinated multicell power allocation to maximize the energy efficiency of the dynamic Time Division Duplexing (TDD) systems in which some cells have downlink transmission and other cells have uplink transmission. We assume that the Base Stations (BSs) are equipped with Multiple-Input Multiple-Output (MIMO) antennas and we have single antenna users. In this scenario, we formulate the energy efficiency maximization problem with respect to both the intracell and intercell interference. Solving this problem, we propose the Energy Efficient Coordinated multicell Power allocation (EECP) algorithm to allocate the transmit power to the beamforming vectors of the downlink BSs and the uplink users. We implement this algorithm for two cases where the downlink BSs employ coordinated or local Minimum Mean Square Error (MMSE) beamformers. The simulation results show that in both situations, the proposed algorithm improves the energy efficiency and the sum rate of the system compared to the case that the maximum power is transmitted by the BSs and the users. Moreover, the EECP algorithm with local MMSE beamforming scheme performs better than the coordinated one, when the number of the served users per cell be equal to the number of the antennas of each BS.