中文摘要：

本文研究多小区多用户的分布式天线系统中最大化用户的最小信干噪比的优化问题。通过块坐标下降法,逐次优化发射功率、天线选择和波束因子中的每一块变量,而固定其余两块变量,使得每个子问题容易求解,减少计算复杂度。由于目标函数中每个子问题都是NP-hard,因此我们基于半正定松弛和高斯随机化的近似算法求解每个子问题。本文逐级优化分布式天线系统的方法首次综合考虑了包括发射功率在内的主要系统参数,仿真结果表明本文所提出的算法优于以往文献中的方法。

英文摘要：

In this paper,the problem under consideration is to maximize the minimum signal-to-interference-plus-noise ratio（SINR） of user terminals（UTs） in a multi-cell multiuser distributed antenna system（DAS）. Based on the Block Coordinate Decent（BCD） method,we propose the strategy of alternatively optimizing over the blocks variables representing the transmit power,the port selection and the beam coefficients. In each iteration,we optimize one block variable at a time and fix the other two,which makes the related subproblem easier and reduces the computational complexity. Because all the subproblems are actually NP-hard,we propose an approximation algorithm based on Semidefinite Relaxation（SDR） and Gaussian randomization. In our paper,we first take all the blocks into consideration to optimize successively in the literature. Simulation result shows that the performance of the proposed method is superior than other known methods in the literature.