基于队列长度的自适应占空比 MAC 协议-《计算机技术与发展》

文章信息/Info

Author(s):: ZHANG Shan-shan; ZHEN Xue; School of Information Science and Engineering,Qufu Normal University,Rizhao 276826,China

摘要:: 由于无线传感器网络中设备电池能量有限,实现能量高效性是其主要考虑的问题。众所周知优秀的数据传输协议对降低能耗,延长网络生命周期有重要意义。而在基于竞争的 MAC 协议中,空闲监听是主要能量消耗来源,所以通常设计较低占空比的 MAC 协议来减少空闲监听时间。但是如果占空比过小,使得网络中所有数据传输集中在较短时间内, 会导致节点无法完成所需要的通信。所以选择合适的节点占空比,对于资源受限的网络来说是一种很重要的节能方法。文中提出了一种新型的异步 MAC 协议 QL-MAC,节点利用 CSMA 争用信道,发送一系列短的信标包唤醒目标节点,采用虚拟载波监听防止串听。不同于其他改变接收节点的方法,该协议从发送节点来考虑,可以根据缓冲区队列长度判断该网络负载,从而自适应调整节点的占空比,使节点及时发送数据,减少时延,并告知接收节点做出相应改变,进一步节省能量。在 OMNET++上实现了 QL-MAC 协议,仿真结果表明 QL-MAC 协议展现了良好的时延和能量有效性。

Abstract:: Due to the limited battery energy in wireless sensor networks,the realization of high energy efficiency is the main problem to be considered. It is well known that excellent data transmission protocols are important for reducing energy consumption and prolonging the life cycle of networks. In MAC protocols based on ompetition,idle listening is the main source of energy consumption,so MAC protocols with lower duty-cycle are usually designed to reduce idle listening time. However,if the duty-cycle is too small,all data transmissions in the network will be concentrated in a relatively short time,which will result in the failure of the nodes to complete the required communication. Therefore,selecting the appropriate duty-cycle is an important energy saving method for resource-constrained networks. We put forward a new kind of asynchronous MAC protocol named QL-MAC.? The protocol uses the CSMA mechanism to contend channel and sends some short beacon packets to wake up the target node,and uses virtual CSMA to reduce the overhearing. Unlike other receiver-initiated protocols,this protocol can judge the load of the network according to the length of the buffer queue focused on the sender,so as to adaptively adjust the duty-cycle of the node.Then receiver decides whether to make a corresponding change.We haveimplemented QL-MAC in the OMNeT++,and the simulation shows that QL-MAC can reduce the end to end delay and energy consumption significantly.