The human body is an extremely challenging environment for the operation of wireless communications systems, not least because of the complex antenna-body electromagnetic interaction effects which can occur. This is further compounded by the impact of movement and the propagation characteristics of the local environment which all have an effect upon body centric communications channels. As the successful design of body area networks (BANs) and other types of body centric system is inextricably linked to a thorough understanding of these factors, the aim of this paper is to conduct a survey of the current state of the art in relation to propagation and channel models primarily for BANs but also considering other types of body centric communications. We initially discuss some of the standardization efforts performed by the Institute of Electrical and Electronics Engineers 802.15.6 task group before focusing on the two most popular types of technologies currently being considered for BANs, namely narrowband and Ultrawideband (UWB) communications. For narrowband communications the applicability of a generic path loss model is contended, before presenting some of the scenario specific models which have proven successful. The impacts of human body shadowing and small-scale fading are also presented alongside some of the most recent research into the Doppler and time dependencies of BANs. For UWB BAN communications, we again consider the path loss as well as empirical tap delay line models developed from a number of extensive channel measurement campaigns conducted by research institutions around the world. Ongoing efforts within collaborative projects such as Committee on Science and Technology Action IC1004 are also described. Finally, recent years have also seen significant developments in other areas of body centric communications such as off-body and body-to-body communications. We highlight some of the newest relevant research in these areas as well as discussing some of the advanced topics which are currently being addressed in the field of body centric communications.

中文翻译：

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以身体为中心的通信无线电信道模型综述

对于无线通信系统的操作来说，人体是一个极具挑战性的环境，尤其是因为可能发生复杂的天线-人体电磁相互作用效应。运动的影响和当地环境的传播特性进一步加剧了这种情况，这些都会对以身体为中心的通信信道产生影响。由于体域网 (BAN) 和其他类型的以身体为中心的系统的成功设计与对这些因素的透彻理解密不可分，因此本文的目的是对传播相关的当前技术水平进行调查主要针对 BAN 的信道模型，但也考虑其他类型的以身体为中心的通信。我们首先讨论电气和电子工程师协会 802.15.6 任务组所做的一些标准化工作，然后重点讨论目前正在考虑用于 BAN 的两种最流行的技术类型，即窄带和超宽带 (UWB) 通信。对于窄带通信，在提出一些已证明成功的特定场景模型之前，先讨论通用路径损耗模型的适用性。人体阴影和小范围衰落的影响也与 BAN 的多普勒和时间依赖性的一些最新研究一起呈现。对于 UWB BAN 通信，我们再次考虑路径损耗以及根据世界各地研究机构开展的大量广泛信道测量活动开发的经验抽头延迟线模型。还描述了科学技术行动委员会 IC1004 等合作项目中正在进行的努力。最后，近年来，以身体为中心的通信的其他领域也取得了重大发展，例如离体通信和身体对身体通信。我们重点介绍这些领域的一些最新相关研究，并讨论目前以身体为中心的通信领域正在解决的一些高级主题。