近年来, 无线传感器网络 (WSNs) 作为国内外一个新兴的研究方向, 吸引了许多研究者和机构的广泛关注. 无线传感器网络具有与传统无线网络不同的特点, 且与应用高度相关. 无线传感器网络主要的一个设计目标是有效地使用网络节点的受限资源 (能量、内存和计算能力), 以最大化网络的服务寿命. 传统网络的介质访问控制 (MAC) 协议, 并不能直接应用于无线传感器网络. 针对无线传感器网络的特点和应用背景, 研究人员提出了很多 MAC 协议. 本文通过分析无线传感器网络的特点, 讨论了影响 MAC 协议设计的有关问题, 着重研究和比较了当前一些重要的无线传感器网络 MAC 协议. 结果表明, 不存在一种适用于无线传感器网络应用的标准 MAC 协议, 好的 MAC 协议必须能在能量有效性和网络性能之间进行折中. 最后, 展望了无线传感器网络 MAC 协议的进一步研究策略和发展趋势.
Wireless sensor networks (WSNs) are different from traditional networks and are highly dependent on applications. One of the main goals of WSNs is to maximize the lifetime of the whole network as well as to use the constrained node resources efficiently, such as energy, memory, and computing capacities. Traditional MAC protocols cannot be applied efficiently to WSNs. Therefore, many new MAC protocols have been designed specifically according to WSNs characteristics and different applications. After introducing the characteristics of WSNs, this paper first describes the sensor network properties that are crucial to the design of MAC protocols. Then, the key mechanisms, virtues, and shortcoming of the existing representative MAC protocols are analyzed, and their performances are compared. The results show that there is no MAC layer protocol that can be accepted as a standard. A good MAC protocol is that it has the ability to make tradeoffs between energy-efficiency and other performances of WSNs according to application conditions. Finally, the future research strategies and trends of MAC protocols in WSNs are summarized.