The increasing traffic demand in cellular networks has recently led to the investigation of new strategies to save precious resources like spectrum and energy. Direct device-to-device (D2D) communication becomes a promising solution if the two terminals are located in close proximity. In this case, the D2D communications should coexist with cellular transmissions, so they must be carefully scheduled in order to avoid harmful interference impacts. In this paper, we outline a novel framework encompassing channel allocation, mode selection and power control for D2D communications. Power allocation is done in a distributed and cognitive fashion at the beginning of each time slot, based on local information, while channel/mode selection is performed in a centralized manner only at the beginning of an epoch, a time interval including a series of subsequent time slots. This hybrid approach guarantees an effective tradeoff between overhead and adaptivity. We analyze in depth the distributed power allocation mechanism, and we state a theorem which allows to derive the optimal power allocation strategy and to compute the corresponding throughput. Extensive simulations confirm the benefits granted by our approach, when compared with state-of-the-art distributed schemes, in terms of throughput and fairness.

中文翻译：

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非正交 D2D 通信的信道、模式和功率优化：混合方法

蜂窝网络中不断增长的流量需求最近导致了对节省频谱和能源等宝贵资源的新策略的研究。如果两个终端距离很近，直接设备到设备 (D2D) 通信将成为一种很有前景的解决方案。在这种情况下，D2D 通信应与蜂窝传输共存，因此必须仔细安排它们以避免有害干扰影响。在本文中，我们概述了一个新的框架，包括 D2D 通信的信道分配、模式选择和功率控制。功率分配在每个时隙开始时以分布式和认知方式完成，基于本地信息，而信道/模式选择仅在一个时期开始时以集中方式执行，包括一系列后续时隙的时间间隔。这种混合方法保证了开销和适应性之间的有效权衡。我们深入分析了分布式功率分配机制，并陈述了一个定理，该定理允许推导出最优功率分配策略并计算相应的吞吐量。与最先进的分布式方案相比，广泛的模拟证实了我们的方法在吞吐量和公平性方面带来的好处。