A multi-user fog radio access network (F-RAN) is designed for supporting content-centric services. The requested contents are partitioned into sub-contents, which are then ‘beamformed’ by the remote radio heads (RRHs) for transmission to the users. Since a large number of beamformers must be designed, this poses a computational challenge. We tackle this challenge by proposing a new class of regularized zero forcing beamforming (RZFB) for directly mitigating the inter-content interferences, while the ‘intra-content interference’ is mitigated by successive interference cancellation at the user end. Thus each beamformer is decided by a single real variable (for proper Gaussian signaling) or by a pair of complex variables (for improper Gaussian signaling). Hence the total number of decision variables is substantially reduced to facilitate tractable computation. To address the problem of energy efficiency optimization subject to multiple constraints, such as individual user-rate requirement and the fronthauling constraint of the links between the RRHs and the centralized baseband signal processing unit, as well as the total transmit power budget, we develop low-complexity path-following algorithms. Finally, we confirm their performance by simulations.

中文翻译：

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一种用于以内容为中心的雾无线电接入网络的新型结构化波束成形

多用户雾无线电接入网络 (F-RAN) 旨在支持以内容为中心的服务。请求的内容被划分为子内容，然后由远程无线电头端 (RRH) 进行“波束成形”以传输给用户。由于必须设计大量波束形成器，这带来了计算挑战。我们通过提出一类新的正则化迫零波束成形 (RZFB) 来解决这一挑战，用于直接减轻内容间干扰，同时通过用户端的连续干扰消除来减轻“内容内干扰”。因此，每个波束成形器由单个实变量（对于正确的高斯信号）或一对复变量（对于不正确的高斯信号）决定。因此，决策变量的总数大大减少以促进易于处理的计算。为了解决受多种约束的能效优化问题，例如个体用户速率要求和 RRH 与集中式基带信号处理单元之间链路的前传约束，以及总发射功率预算，我们开发了低-复杂性路径跟踪算法。最后，我们通过模拟来确认它们的性能。