The Implementation And Research Of Multi-coupling Intra-body Communication Physical Layer Based On Virtual Instrument

Wireless body area network(WBAN)technology has been widely used in health care and consumer electronics etc.,which brings countless convenience for human beings.When compared to existing short-distance wireless communication such as Bluetooth,ZigBee,and IrDA etc.,intra-body communication technology has the advantages of ultra-low power consumption,weaker outer radiation,and being not easy to be constrained in bandwidth etc.,which means the technology has broader and more promising application in WBAN.Recently,most of the researches of intra-body communication focus on software simulation or study of hardware system.In general,simulation cannot reveal the authentic characteristics of body channel,while the establishment of hardware system inherently has the disadvantages of being not easy to adjust parameters and spending more time in constructing.Virtual instrument can bring vast convenience and foster the research for physical layer in intra-body communication with its powerful measurement ability and the merit of adjustable parameters in test system.The paper focused on the modeling and verification of equivalent circuit for multi-coupling intra-body communication.Moreover,the research platform for the communication based on virtual instrument was constructed,which was designed to provide guidance and reference for the implementation of intra-body communication hardware system.Main aspects of research are as follow.First of all,the correlation theories of intra-body communication such as wireless body area network technology,physical layer of intra-body communication and electromagnetic characteristics of human body were introduced to support the part of modeling of equivalent circuit and implementation of system and so on in the following chapters.Then,equivalent circuit for multi-coupling intra-body communication was modeled based on virtual instrument.Via the comparison of experimental results among three kinds of measurement ways which are direct measurement,floating measurement under independent power supply and isolated measurement under optic-coupler,the correct method of measurement based on virtual instrument was acquired.In addition,the proposed equivalent circuits were also verified.Moreover,power water-filling algorithm was introduced in the estimation model of channel capacity in human body,and the capacity of galvanic type was 554 Kbit/s approximately under 10cm channel length via the method of channel segmentation.Moreover,the research platform for intra-body communication based on virtual instrument was constructed,which could achieve three kinds of modulation-demodulation system.The panel of instrument was in a way of interaction,and software demodulation methods for ASK and FSK and Costas Loop for BPSK in LabVIEW were also proposed.In addition,the performance of the platform was also evaluated.Finally,a fully floating capacitive-coupling intra-body communication transceiver was designed according to the parameters provided by the intra-body communication research platform based on virtual instrument.The designed transceiver was verified to have better performance according to the outcome of test,whose BER was lower than 1e-5.What's more,it was applied in a multi-nodes electrical stimulation system based on WBAN as well,which turned out to be feasible and effective after test.In summary,intra-body communication platform based on virtual instrument offered a new way for the research of correlated characteristics of intra-body communication.It was a parameter adjustable or dynamic platform which could realize information transmission between transmitter and receiver under different coupling ways,different channel length,etc.,and provide guidance and reference for the implementation of intra-body communication hardware system.The transceiver applied in multi-nodes electrical stimulation system also indicated that intra-body communication technology had a promising future in WBAN.