Many Internet of Things (IoT) networks with Radio Frequency (RF) powered devices operate over a shared medium. They thus require a channel access protocol. Unlike conventional networks where devices have unlimited energy, in an RF-powered IoT network, devices must first harvest RF energy in order to transmit or/and receive data. To this end, this survey presents the {\em first} comprehensive review of prior works that employ contention-based and contention-free protocols in IoT networks with one or more {\em dedicated} energy sources. Specifically, these protocols work in conjunction with RF-energy sources to deliver energy delivery or/and data. In this respect, this survey covers protocols based on Aloha, Carrier Sense Multiple Access (CSMA), polling, and dynamic Time Division Multiple Access (TDMA). Further, it covers successive interference cancellation protocols. It highlights key issues and challenges addressed by prior works, and provides a qualitative comparison of these works. Lastly, it identifies gaps in the literature and presents a list of future research directions.

翻译：许多采用射频供电设备的物联网（IoT）网络在共享介质上运行，因此需要信道接入协议。与传统网络中设备具有无限能量不同，在射频供电物联网网络中，设备必须首先采集射频能量才能进行数据发送和/或接收。为此，本综述首次全面梳理了在具有一个或多个专用能量源的物联网网络中采用基于竞争和无竞争协议的先前工作。具体而言，这些协议与射频能量源协同工作以实现能量传输和/或数据传输。本综述涵盖了基于Aloha、载波侦听多路访问（CSMA）、轮询和动态时分多址（TDMA）的协议，同时涵盖了连续干扰消除协议。重点阐述了先前工作所解决的关键问题与挑战，并对这些工作进行了定性比较。最后，指出了文献中的空白领域，并提出了未来研究方向清单。