Optimal Resource Allocation In Energy Harvesting-Powered Body Sensor Networks

Wireless Body Area Network (WBAN) is a human-centered Wireless Sensor Net-work (WSN) with low power consumption, which consists of a series of sensors dis-tributed on the human body. WBAN is widely used in medical health, equipment test-ing, sports training, entertainment and sports fields. Remote remote e-health has a more pressing needs and major significance among all those applications, due to that it can greatly reduce the cost of medical services at the same time it can significantly improve the quality of service in medical field. In human’s daily life, since wireless body area channels are offen blocked by the activities of human body, which making the wire-less body area network channels survey a strong shadowing effect, thus, it is a huge challenge to guarantee the reliability of wireless body area network data transmission. Meanwhile, it may happen that some part of the physiological signal sensors are im-planted in the human body. Thus, it is difficult or simply can not easily replace the sensor’s battery, so from the perspective of user-friendliness and replacing batteries complexity, how to provide an easy to use, sustainable health-care services is a huge challenge. Finally, since the remote electronic medical system needs to adapte to a wide variety of physiological signals, so the e-health system needs to be able to deal with the needs of the heterogeneous of the wireless body area network. In order to provide a sus-tainable, high quality of service (QoS), high availability service for remote electronic medical system, in this paper, we carefully design the resource allocation strategies for WBANs according to the characteristics of wireless body area network:(1) Based on the WBAN’s characteristics and the characteristics of energy harvesting, we first establish the system model, energy harvesting model and packets arrival model. Based on the above model, we first analyze the statistical properties of the system, through which we can see the long term performance of the entire system. We could use it as the guide for the practical system settings.(2) A energy harvesting based resource allocation strategy is proposed for the remote electronic medical system. Through joint optimize transmission power allocation and transmission slot allocation, the proposed strategy can provide a sustainable, high quality of service (QoS), high availability service. Based on the optimal slot allocation, the proposed strategy can achieve the system requirements for the het-erogeneity of WBANs. Simulation results show that the proposed energy harvest-ing based resource allocation strategy, compared to the "greedy resource allocation policy", can provide a higher quality of service and stable performance. Besides, the proposed strategy is very close to the theoretical performance. (3) In order to achieve energy balance in the wireless body area networks, a cooperation resource allocation strategy is designed for WBANs by combining the cooperative relay data transmission strategy with energy sharing method. The combined strat-egy fully exploits the advantages of the two strategies. It can not only relay data, but also sharing energy, thereby reducing the shadow effects and allowing the system to achieve energy balance destination. Simulation results show that the proposed cooperation resource allocation strategy, compared to simple data relay transmis-sion strategy, can further improve the quality of service on the remote electronic medical system and makes the whole system to achieve energy balance.