Research On Link Reliability During Human Movement In Wireless Body Area Networks

Wireless body area network is defined as a body-centric system,and it has multiple features such as information collection,data processing and wireless transmission.Due to the rapid development of aging population and a serious shortage of medical resources,there are great application requirements in modern health care field such as remote health care and community health care.So people pay more and more attention to the person-centered wireless networks.The biggest difference between wireless body area network and other traditional networks is that it is a body-centric network.It needs to transmit human physiological information reliably and real-time.As the complexity of body surface feature,the body structure and environment,and the topology of wireless body area network changes dynamically with the body motion,the channel characteristics of wireless body area network is relatively complicated.The instability of channel environment brings a series of difficulties to the realization of reliable transmission.So regarding the special environment of human body,this paper focuses on how to improve the reliability of communication and guarantee the quality of service under the dynamic network topology condition of the wireless body area network.By analyzing the main application scenarios of wireless body area networks,we establish two motion models according to the most common body motion of human,which is walking and running.And the models are used in the designing of the transmission mechanism of wireless body area networks.Meanwhile,considering the influences of the differences of human body and the position which the wireless sensors are placed,we make some experiments to verify the influences,and then make a conclusion.Then,in order to solve the problem of low reliability during running in a wireless body area network in practice,this paper combines the motion feature during human movement,considering the different channel performances of different sensor position,proposes a joint relay selection and power control scheme.By analyzing the received signal strength,source node position,sensor movement(evaluated by accelerometer),this scheme changes the network topology dynamically,to adapt to the unstable situation caused by human motion.After experiment,packet loss ratio,network lifetime are evaluated,this scheme can achieve a good tradeoff between reliability and energy consumption comparing to the single relay selection scheme or power control scheme.