Body Area Communications: Channel Modeling, Communication Systems, and EMC

Chapter 4

Body Area Channel Modeling

4.1 Introduction

Body area communications differs from traditional radio communications due to human body proximity effects. Human body tissue is a complicated frequency-dependent dielectric material with relatively high permittivity and certain conductivity. Radio signals propagating in the body area are significantly affected by human body tissue (Zasowski et al., 2006). Propagation mechanisms in the body area are also frequency-dependent as introduced in Chapter 2. The resulting received signal is subject to the transmission channel, the distance between the transmitter and the receiver, transmitter and receiver antenna positions, tissue dielectric properties along the transmission channel, body curvature and so on. Channel modeling is the initial step to explore and investigate the body area communications. An adequate propagation channel model is essential for the design of a body area communication system. The ultimate performance limits of body area communication systems, as well as the performance of practical systems, are determined by the channel they operate in.

Body area channels can be classified into wearable channels and implant channels according to the locations of the transmitter and receiver devices on or in or off the body. Wearable channels have all of the devices on body, while implant channels have some devices in body which communicate with on- or off-body devices. Figure 4.1 illustrates several typical body area channels ...