This paper considers hybrid beamforming by combining an analog beamformer with a new regularized zero forcing baseband one, for multi-user millimeter-wave networks under a limited number of radio frequency (RF) chains. Three popular scenarios are examined: i) the number of users is up to the number of RF chains in a single-cell network, ii) the number of users is up to twice the number of RF chains in a single-cell network, and iii) the number of users is up to twice the number of RF chains in each cell of a two-cell network. In the second and third scenarios, we group the users into two categories of cell-center users as well as cell-edge users and serve them in two different time fractions. In the third scenario, we propose to suppress the inter-cell interference by serving the cell-center and cell-edge users in alternate fractional-time slots. In all the three scenarios, we determine the optimal power allocation maximizing the users' minimum rate. Finally, low-complexity path-following algorithms having rapid convergence are developed for the computation of the optimal power. Our simulation results show that the proposed algorithms achieve a clear performance gain over the existing benchmarkers.

中文翻译：

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多用户毫米波网络的混合波束成形


本文考虑了混合波束成形，将模拟波束成形器与新的正则化迫零基带相结合，用于有限数量的射频 (RF) 链下的多用户毫米波网络。研究了三种流行的场景：i) 用户数量最多为单小区网络中 RF 链的数量，ii) 用户数量最多为单小区网络中 RF 链数量的两倍，以及iii) 用户数量最多为双小区网络中每个小区中 RF 链数量的两倍。在第二和第三种场景中，我们将用户分为小区中心用户和小区边缘用户两类，并在两个不同的时间段为他们提供服务。在第三种情况中，我们建议通过在交替的分数时隙中为小区中心和小区边缘用户提供服务来抑制小区间干扰。在所有三种情况下，我们确定最大化用户的最低速率的最佳功率分配。最后，开发了具有快速收敛的低复杂度路径跟踪算法来计算最佳功率。我们的仿真结果表明，所提出的算法比现有基准测试器获得了明显的性能提升。