A simple downlink transmission power control method for worst user throughput maximization in heterogeneous networks

This paper proposes a simple downlink transmission power control method in heterogeneous networks aiming at maximization of the worst user throughput. The proposed method requires inter-base station (BS) cooperation. However, the proposed method can be implemented by sharing only a single metric among BSs, which is different from the conventional BS cooperative transmission power control methods that require exchanging a large amount of channel state information (CSI) of all users among BSs. In the proposed method, cooperating BSs share the tentative worst user throughput within the cooperating cells, so the proposed method does not require additional CSI feedback from the user terminals. Using this shared metric information, each BS updates its transmission power so that the target throughput is achieved for all users served by that BS. Although the proposed method is computationally efficient and the amount of the shared information via the backhaul is very limited, the worst user throughput achieved using the proposed method is very close to the upper bound performance. Multi-cell simulation evaluation shows that the proposed method yields advantageous throughput performance and a transmission power reduction effect compared to conventional approaches.