Full duplex (FD) systems are able to transmit and receive signals over the same frequency band simultaneously with the potential of even doubling the spectral efficiency in comparison with traditional half duplex (HD) systems. When combined with relaying, FD systems are expected to dramatically increase the throughput of future wireless networks. However, the degrading effect of self-interference (SI) due to the simultaneous transmission and reception at the relay threatens their efficient rollout in real-world topologies. At the same time, non-orthogonal multiple access (NOMA) can further increase the spectral efficiency of the network. In this article, we present how buffering at the relays can be integrated with FD and NOMA in order to improve the performance of relay networks. More specifically, the key points for the successful integration of buffer-aided relays with spatial sharing paradigms are presented, and details on buffer-state-information-based relay selection and its fully distributed implementation are discussed. Furthermore, a mathematical framework for the analysis of FD and HD buffer-aided relay networks is rigorously discussed. Performance evaluation shows the importance of data buffering toward mitigating SI and improving the sum-rate of the network. Finally, the goal of this work is both to summarize the current state of the art and, by calling attention to open problems, to spark interest toward targeting these and related problems in relay networks.

中文翻译：

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当缓冲辅助中继遇到全双工和NOMA

与传统的半双工（HD）系统相比，全双工（FD）系统能够同时在同一频带上发送和接收信号，并且频谱效率甚至有可能翻倍。与中继结合使用时，FD系统有望大大提高未来无线网络的吞吐量。但是，由于中继器同时进行发送和接收而导致的自干扰（SI）的降级效果威胁了它们在实际拓扑中的有效部署。同时，非正交多路访问（NOMA）可以进一步提高网络的频谱效率。在本文中，我们介绍了如何将中继的缓冲与FD和NOMA集成在一起，以提高中继网络的性能。进一步来说，介绍了成功实现具有空间共享范式的缓冲器辅助继电器集成的要点，并讨论了基于缓冲器状态信息的继电器选择及其完全分布式实现的细节。此外，严格讨论了用于FD和HD缓冲区辅助中继网络分析的数学框架。性能评估显示了数据缓冲对于减轻SI和提高网络总速率的重要性。最后，这项工作的目的既是总结当前的技术水平，又是通过引起人们对开放性问题的关注，激发人们针对中继网络中这些问题和相关问题的兴趣。讨论了基于缓冲区状态信息的中继选择及其完全分布式实现的细节。此外，严格讨论了用于FD和HD缓冲区辅助中继网络分析的数学框架。性能评估显示了数据缓冲对于减轻SI和提高网络总速率的重要性。最后，这项工作的目的既是总结当前的技术水平，又是通过引起人们对开放性问题的关注，激发人们对针对中继网络中的这些问题和相关问题的兴趣。讨论了基于缓冲区状态信息的中继选择及其全分布式实现的细节。此外，严格讨论了用于FD和HD缓冲区辅助中继网络分析的数学框架。性能评估显示了数据缓冲对于减轻SI和提高网络总速率的重要性。最后，这项工作的目的既是总结当前的技术水平，又是通过引起人们对开放性问题的关注，激发人们针对中继网络中这些问题和相关问题的兴趣。