Beamforming in Distributed Antenna Systems Based on Successive Convex Approximation and Dual Decomposition

In distributed antenna systems (DASs), the main process units (MPUs) undertake all of the computing tasks in the centralized beamforming algorithm, which causes high computation complexity at the MPU. This paper proposes a distributed beamforming algorithm in DASs to reduce the computation complexity. However, the original problem is non-convex and inseparable, which hinders solving the original problem in a distributed manner. To overcome these difficulties, we first construct a sequence of separable convex approximations of the original problem based on the successive convex approximation (SCA) technique and then decompose their dual to yield the distributed beamforming algorithm. The convergence and signalling overhead of the proposed algorithm are also provided. The simulation results show that the proposed algorithm has higher energy efficiency than the traditional algorithms and lower computation complexity than the centralized SCA algorithm.