Device-to-device (D2D) communications has been realized as an effective means to improve network throughput, reduce transmission latency, and extend cellular coverage in 5G systems. Network coding is a well established technique known for its capability to reduce the number of retransmissions. In this article, we review stateof- the-art network coding in relay-based D2D communications, in terms of application scenarios and network coding techniques. We then apply two representative network coding techniques to dual-hop D2D communications and present an efficient relay node selecting mechanism as a case study. We also outline potential future research directions, according to the current research challenges. Our intention is to provide researchers and practitioners with a comprehensive overview of the current research status in this area and hope that this article may motivate more researchers to participate in developing network coding techniques for different relay-based D2D communications scenarios.

中文翻译：

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基于中继的设备到设备通信中的网络编码


设备到设备 (D2D) 通信已成为提高 5G 系统网络吞吐量、减少传输延迟和扩展蜂窝覆盖范围的有效手段。网络编码是一种成熟的技术，以其减少重传次数的能力而闻名。在本文中，我们从应用场景和网络编码技术方面回顾了基于中继的 D2D 通信中最先进的网络编码。然后，我们将两种代表性网络编码技术应用于双跳 D2D 通信，并提出一种高效的中继节点选择机制作为案例研究。我们还根据当前的研究挑战概述了未来潜在的研究方向。我们的目的是为研究人员和实践者提供该领域当前研究现状的全面概述，并希望本文能够激励更多的研究人员参与开发针对不同的基于中继的 D2D 通信场景的网络编码技术。