Massive machine-type communications (mMTC) is one of the main services delivered by the fifth Generation (5G) mobile network. The traditional cellular architecture where all devices connect to the base station is not energy efficient. For this reason, the use of device-to-device (D2D) communications is considered to reduce the energy consumption of mMTC devices. The main idea is to use nearby user equipment (UE) as a relay and establish with it D2D communication. However, the relay selection process also consumes energy, and this consumption can be significant compared to the energy consumed during the data transmission phase. In this paper, we propose a distributed energy-efficient D2D relaying mechanism for mMTC applications. This mechanism favors the selection of the UEs with low path loss with the mMTC device. Through mathematical analysis and simulations, we show that our mechanism allows a reduction of the total energy consumption of mMTC devices (up to 75% compared to direct transmission) when they have an unfavorable link budget. Moreover, our mechanism achieves almost constant energy consumption for a large range of UE densities and distances between the mMTC device and the base station.

中文翻译：

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5G D2D 通信节能发现协议中的距离感知中继选择


大规模机器类型通信（mMTC）是第五代（5G）移动网络提供的主要服务之一。所有设备都连接到基站的传统蜂窝架构并不节能。因此，使用设备到设备（D2D）通信被认为可以降低mMTC设备的能耗。主要思想是使用附近的用户设备（UE）作为中继并与其建立D2D通信。然而，中继选择过程也会消耗能量，并且与数据传输阶段消耗的能量相比，这种消耗可能是相当大的。在本文中，我们提出了一种用于 mMTC 应用的分布式节能 D2D 中继机制。该机制有利于选择与mMTC设备具有低路径损耗的UE。通过数学分析和模拟，我们表明，当 mMTC 设备的链路预算不利时，我们的机制可以降低 mMTC 设备的总能耗（与直接传输相比最多减少 75%）。此外，我们的机制在大范围的UE密度和mMTC设备与基站之间的距离下实现了几乎恒定的能耗。