低占空比无线传感器网络同步MAC协议最优信标间隔分析  

The Optimal Beacon Interval for Synchronous MAC in Low Duty-Cycle Wireless Sensor Networks

作　　者：邢宇龙[1] 陈永锐[1] 易卫东[1] 段成华[1] 

机构地区：[1]中国科学院大学电子电气与通信工程学院,北京100049

出　　处：《计算机研究与发展》2016年第9期2009-2015,共7页Journal of Computer Research and Development

基　　金：国家科技支撑计划基金项目(2012BAJ24B01)~~

摘　　要：能量效率是无线传感器网络协议设计的首要考虑因素.无线传感器网络中,介质访问控制层(medium access control,MAC)协议通过降低节点的占空比来降低网络能耗,延长网络的生命周期.相比其他MAC协议,尽管同步MAC需要周期性分发信标来保持严格的时间同步,但却在数据传输方面具有更高的能量效率.信标间隔的长短直接影响同步MAC能量效率的高低.一方面,较短的信标间隔导致较高的同步开销;另一方面,由于时钟漂移的影响,较长的信标间隔会引起较大的保护时间,从而导致空闲侦听能耗的增加.因此,同步开销和空闲侦听这2部分能耗之间存在一个最优折中.分析了低占空比无线传感器网络同步MAC的最优信标间隔问题,提出了一种采用最优信标间隔的TDMA MAC协议(Opt-TDMA).实验表明:Opt-TDMA的能量效率优于非最优信标间隔的TDMA协议和同步MAC协议SCP-MAC.Energy efficiency is a fundamental theme in the design of wireless sensor networks protocols, especially for medium access control （MAC） protocols. An energy-efficient MAC protocol can significantly elongate the lifetime of wireless sensor networks by reducing the duty-cycle of sensor nodes to an ultra-low level. Synchronous MAC can be even more efficient in data transfer at the cost of requiring tight time synchronization through periodical beacon dissemination. The length of the beacon interval may greatly affect the energy efficiency of a synchronous MAC. A shorter beacon interval leads to higher synchronization cost due to frequent beacon sending and receiving, while a longer beacon interval will lead to a larger guard time and longer idle listening due to clock drift. Therefore, there is a tradeoff between these two parts of energy consumption. In this paper, we investigate the optimal beacon interval for synchronous MAC in low duty-cycle sensor networks, and then present a strategy that adaptively utilizes the optimal beacon interval in a TDMA-based MAC protocol （called Opt-TDMA）. By configuring the beacon interval to its optimal value according to the data packets rate and network size, Opt-TDMA can reduce the overall power consumption of both sending/receiving beacons and data packets. Experimental results demonstrate that Opt-TDMA is more energy-efficient than pure TDMA protocol and SCP-MAC by using optimal beacon interval and contention-free transmission.

关 键 词：信标间隔 同步MAC协议 低占空比 能量效率 无线传感器网络 

分 类 号：TP393[自动化与计算机技术—计算机应用技术]