关键词：无线传感器网络；医疗保健；物联网；MAC
摘 要：Wireless sensor networks (WSNs) are increasingly gaining impact in our day to day lives. They are finding a wide range of applications in various domains, including health care, assisted and enhanced-living scenarios, industrial and production monitoring, control networks, and many other fields. In future, WSNs are expected to be integrated into the "Internet of Things", where sensor nodes join the Internet dynamically, and use it tocollaborate and accomplish their tasks. As wireless sensor networks being used in many emerging applications the requirement of providing high quality of service (QoS) is becoming ever more necessary. This highlights major issues like collision, scalability, latency, throughput and energy consumption. In addition mobile sensor network faces further challenges like link failure, neighbourhood information, association, scheduling, synchronisation and collision. Medium Access Control (MAC) protocols play vital role in solving these key issues. This chapter presents the fundamentals of MAC protocols and explains the specific requirements and problems these protocols have to withstand for WSN. The QoS is addressed for both static and mobile sensor networks with detailed case study of the IEEE 802.15.4 WPAN standard. Research challenges with literature survey and further directions are also discussed. The chapter ends with conclusions and references.