Revisit to Basics of Body-Centric Wireless Communications

In recent years, the technology and various systems of human body communication (HBC) have been developed and widely used in many different applications including healthcare, nursing, sports, games, assistive tools for workers, and so on.HBC utilizes the human body as a transmission medium to transmit or receive wireless signals serving as one of promising physical layer solutions for body area networks (BANs), as shown in Fig. 1 [1].HBC can be implemented in a wide range of smart and small wearable devices, such as healthcare bands, smart watches, smart glasses, smart shoes, etc.These devices contain transmitters/receivers for wireless communication.Equivalent circuit models including a number of resistors and capacitors have been usually employed for a practical design of such transmitters/receivers [1].However, the design is sometimes sensitive to changes of device locations, human-body size and shape, surrounding environments, etc.