卫小伟

(陕西交通职业技术学院信息工程系　西安　710018)



WSN中一种节能的按需调度协作式MAC协议研究*

卫小伟

(陕西交通职业技术学院信息工程系西安710018)

摘要能量空洞问题影响了由电池供电的多跳无线传感器网络的寿命。为此,论文提出一种按需调度协作式MAC协议(ODSC-MAC),综合采用按需策略及可扩展(传输)范围的传感器协作机制,ODSC-MAC协议解决了多跳WSN网络进行协作式传输(CT)时存在的时空问题,延长了网络寿命。另外,采用正交管线占空比调度以缓解流量竞争,同时设计了一种基于预定策略的唤醒机制以使协作节点时间同步,并为CT传输范围扩展提供支持。与现有的MAC协议相比,基于REACT的NS-2仿真结果表明,该协议既明确考虑了CT传输的开销及流量密集时控制报文的实际故障,又使网络运行时间提升了近80%。

关键词无线传感器网络; 能量空洞; 协作传输; 按需调度; 网络寿命

An Energy-saving On-demand Scheduling Cooperative MAC Protocol in Wireless Sensor Networks

WEI Xiaowei

(Department of Information Engineering, Shanxi College of Communication Technology, Xi’an710018)

AbstractThe energy hole problem limits the lifetime of battery powered multi-hop wireless sensor networks(WSNs). To solve this problem, An On-demand Scheduling Cooperative MAC protocol(ODSC-MAC) is proposed. By combining an on-demand strategy and sensor cooperation intended to extend range, ODSC-MAC tackles the spatio-temporal challenges for performing cooperative transmission(CT) in multi-hop WSN, to prolong the lifetime of the network. In addition, orthogonal and pipelined duty-cycle scheduling are used for reducing the traffic contention, and a reservation-based wake-up scheme is devised to bring cooperating nodes into temporary synchrony to support CT range extension. Compared with existing MAC protocols, our NS-2 simulations with REACT show that while explicitly accounting for the overhead of CT and practical failures of control packets in dense traffic, ODSC-MAC still gives almost 80% increase in network lifetime.

Key Wordswireless sensor networks, energy hole, cooperative transmission, on-demand scheduling, lifetime of the network

Class NumberTP393

1引言

众所周知,能量空洞问题影响了由电池供电的多跳无线传感器网络的寿命[1~2]。Sink附近的节点由于负载较重,能量耗尽较早,容易出现能量空洞问题:Sink附近的节点既要传输自己的报文,又要为距离Sink较远的节点转发报文。文献[3]已经证明,残余能量激活式协作传输(REACT)转发策略可纠正能量不均衡现象,将网络寿命延长2倍甚至更多。然而,该策略没有考虑协作式传输(CT)导致的额外控制开销。同时也没有考虑如何将REACT与占空比结合起来,而占空比是节约能量、提升WSN网络寿命的常用方法。

文献[4]的研究表明,MAC协议的能量消耗主要集中于空闲侦听、开销和冲突及数据传输和接收。……