Joint 3D Beamforming and Power Allocation in Distributed Antenna Systems

Distributed antenna system (DAS) and three-dimensional (3D) beamforming are two potential techniques to enhance the data rate of 5G wireless communication systems. Combining these two techniques together can further improve the system performance. In this paper, we investigate the joint 3D beamforming and power allocation scheme in DASs. We first analyze the data rate of the system and then formulate the problem to maximize the overall network data rate considering the constraints, including transmit power, antenna tilt, and users’ quality of service (QoS) requirements. The formulated problem is nonlinear and difficult to find the solution directly. Therefore, we develop a two-step algorithm to solve the problem, where it first determines the optimal antenna downtilts for 3D beamforming and afterwards deals with the power allocation based on sub-gradient method. Simulation results demonstrate the performance improvement of the proposed algorithm.

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