Study Of Access Protocols In Wireless Body Area Networks Based On IEEE 802.15.4

With the development of wireless communication techniques and sensor techniques, wireless sensor networks (WSNs) have more influences on the medical applications. The technology of wireless body area network (WBAN) is emerging as a result. Even a WBAN is similar with a traditional WSN in some aspects, it has distinct difference on the traffic model between each other. A WBAN is expected to support several different applications including the medical and multi-media traffics. In other words, the traffic category could be on-demand, emergency or normal.The thesis firstly reviews the main functions of IEEE 802.15.4, which is widely used in wireless personal area networks (WPANs). Then the thesis introduces the basic architecture, characteristics and the challenges of the study of WBAN. In a WBAN, considering a sensor node is always battery powered, it is hard or impossible to recharge the battery especially for an implantable node. Therefore, how to save the energy becomes the most important issue in a WBAN. With focus on the energy efficiency, the thesis proposes two medium access control (MAC) protocols in WBANs based on IEEE 802.15.4 superframe structure. The first one employs mini-slot ALOHA as the contention access scheme to support multiple physical layer (PHY) techniques and adaptive slot allocation in the contention-free period. In the second one the priority issue is considered to guarantee the quality of service (QoS) of different applications. Moreover, the slot allocation efficiency is also studied in the second protocol. Finally, the thesis is concluded with the discussion of the future work in WBANs.