The Internet of Things (IoT) is currently used in many wireless sensor network (WSN) applications. Conventionally, the WSN’s energy consumption is considered as one of the prime concerns. The energy consumption is mostly due to the sensing, data processing, communications and other wasted energies such as idle listening, collisions and overhearing. These sensor nodes are regularly powered by an external power source and consequently have a shorter lifetime. Fortunately, different approaches for wireless energy harvesting (WEH) have been improved. Thus, wake-up radio (WuR) becomes a remedy for WEH which provides active, passive and semi-passive circuits consumption and other protocols. For instance, the most used, convincing and productive go to passive WuR which can significantly increase the network lifetime in a sensor network (SN) by decreasing unnecessary idle listening. Eventually, this paper proposes a state of the art in active, semi-passive, centering more on passive WuR and covers the applications areas. Then, an overview of WuR related to physical, medium access control (MAC) and routing layers. Lastly, the paper accentuates the potential research opportunities for wake-up technology for future IoT applications.

物联网 (IoT) 目前用于许多无线传感器网络 (WSN) 应用。传统上，WSN 的能源消耗被认为是主要关注点之一。能源消耗主要是由于传感、数据处理、通信和其他浪费的能源，如空闲监听、碰撞和偷听。这些传感器节点定期由外部电源供电，因此寿命较短。幸运的是，无线能量收集 (WEH) 的不同方法已经得到改进。因此，唤醒无线电 (WuR) 成为 WEH 的一种补救措施，它提供有源、无源和半无源电路消耗和其他协议。比如最常用的，令人信服且富有成效的转向无源 WuR，它可以通过减少不必要的空闲侦听来显着增加传感器网络 (SN) 中的网络寿命。最后，本文提出了主动、半被动的最新技术，更多地以被动 WuR 为中心并涵盖应用领域。然后，概述与物理、媒体访问控制 (MAC) 和路由层相关的 WuR。最后，本文强调了未来物联网应用唤醒技术的潜在研究机会。