面向工业无线汇聚网络的高吞吐率MAC协议

汇聚网络是工业传感器网络的常用拓扑形式。汇聚网络的隐藏终端是影响网络吞吐率的重要因素,目前常用信道预留机制来加以解决。此外,随着物理层数据传输速率的不断提高,相对短报文的现象日渐突出,使得用于信道预留的控制报文的开销相对增加。现有的IEEE802.11 DCF不能同时有效应对这两个现象。提出了取消信道预留方式来克服相对短报文问题,而对于由于信道预约取消所导致的隐藏终端问题,则以随机发送机制解决。为了获得最优的发送概率,设计了APCSMA协议,该协议以最大化节点吞吐率为目标,提出吞吐率最大化的必要条件,基于该必要条件,在主干扰模型下推导出节点均匀分布情况下的最优报文发送概率。从理论上分析了协议的网络吞吐率、延迟和能量效率。仿真结果和分析表明,APCSMA协议对于工业无线汇聚网络具有广泛的适用性。

High-throughput MAC Protocol for Industrial Convergent Wireless Networks

Convergent topology is a widely used topology in industrial wireless sensor networks,and its throughput is adversely influenced by the hidden terminal problem.Nowadays,channel reservation scheme is utilized to deal with the notorious hidden terminal problem.However,the increasing data rate in the physical layer introduces relatively short packets,which results in the relative increase of the overhead of the channel reservation scheme.Since IEEE 802.11 DCF cannot effectively deal with the two problems mentioned above simultaneously,we proposed a novel protocol,termed as APCSMA,for convergent topology.Specifically,the channel reservation scheme is eliminated to deal with the relatively short packets,and an opportunistic transmission scheme is employed to deal with the hidden terminal problem.A necessary condition has been developed for the optimal transmission probability to maximize the per-node throughput.Together with the assumption of uniformly distributed nodes,the optimal transmission probability is derived under the primary interference model.Then,the performances of our protocol are thoroughly investigated in terms of network throughput,delay and energy efficiency.Our analytical results verified by simulations and the results demonstrate the efficiency of the proposed protocol in practical industrial convergent wireless networks.