Performance Evaluation Of IEEE 802.15.6 And Energy-efficient MAC Design

With the growth in global aging, baby boomers and various diseases, existing medical resources can hardly meet the requirements of people in healthcare area. What's more, most people are eager to pursue a more convenient and comfortable life nowadays. Thus the Wireless Body Area Networks(WBANs) emerged and attracted a great interest of people.WBAN is an import branch of Internet of Things(IOT) and introduces human body into the communication network, which integrates the micro electronic circuits, biomedical sensors and wireless communication technologies. With collecting the biomedical information and environment parameters around human body, WBANs provide high convenient and effective healthcare and personal entertainment services, which shows a broad development prospects.IEEE 802.15.6 was published as the international standard specifically designed to support and promote the development of WBANs. With comprehensive technical guidance in medium access control(MAC), physical layer(PHY) and security service, IEEE 802.15.6 can support extremely low power, high quality of service(Qo S) and human safety, which provides powerful foundation for WBAN designers. This paper aims to make a performance evaluation of IEEE 802.15.6 and design a high energy-efficient MAC protocol for health monitoring application.In order to satisfy the heterogeneous service requirements from different applications, IEEE802.15.6 assigns different user priority(UP) for different traffic which affects the parameters in access method. With implemented the WBAN module in the MIRAI-SF platform,this paper evaluates the performance of IEEE 802.15.6 when user priority, data arrival rate and the occupation of medical traffic vary. The simulation results show that IEEE 802.15.6guarantees high Qo S for higher UPs, especially for the emergency data, at the cost of performance of lower UPs. It also shows that IEEE 802.15.6 CSMA/CA can achieve high Qo S when there is lightweight medical traffic in the network. But it suffers deterioration when the medical traffic holds a large proportion of total traffic due to fierce collisions.Health Monitoring is one of the most important applications in WBANs. It is necessary to design a high energy-efficient and reliable MAC protocol due to the limited energy and size of nodes in health monitoring. This paper proposes a high energy-efficient MAC protocol named Two Round Reservation MAC(2R MAC). With analyzing the characters of data in health monitoring, 2R MAC conducts two round reservations to raise allocation requests according to the data type. 2R MAC also builds a relationship between the appropriate number of allocation slots and data arrival rate for a specific node. In addition, in order to guarantee the emergency information can be delivered as soon as possible, 2R MAC determines the transmission order of urgent data by introducing a new health severity index.The energy analyzation results show that 2R MAC achieves higher energy efficiency and longer lifetime compared with IEEE 802.15.6 and One Round Reservation MAC(1R MAC).