SEEL:无线传感器网络下自适应、低延迟的节能媒质接入控制协议

无线传感器网络有着广泛的应用前景,然而由于传感器节点能量有限,因此传感器网络上运行的协议必须具备能量有效性以获得较长的生命周期.而媒质接入控制子层是节点能量消耗的主要所在,因此无线传感器网络设计的关键问题之一是媒质的接入控制.提出了一种自适应低延迟的节能MAC协议——SEEL协议,根据当前的网络负载自适应地调节竞争窗口的大小,从而减小节点数据传送的碰撞几率和由于碰撞而导致的能量消耗;采用了快速退避机制,减少了节点在退避过程中的空闲监听时间;扩展了RTS/CTS消息机制,可减少节点在每帧活动阶段的时间以及减小数据的延迟,两者都能节约能量的使用.实验结果显示,SEEL协议具有比S-MAC和TEEM协议更好的性能.     

An asynchronous scheduled MAC protocol for wireless sensor networks

Wireless sensor networks (WSNs) comprise a number of autonomous sensors and one or more sinks to cooperatively monitor physical or environmental conditions. Energy efficiency is a key design factor of a MAC protocol for WSNs. Due to the importance of the problem, a number of energy efficient MAC protocols have been developed for WSNs. Preamble-sampling based MAC protocols (e.g., B-MAC and X-MAC) have overheads due to their preambles, and are inefficient at large wakeup intervals. SCP-MAC, a synchronous scheduled energy-efficient scheduling MAC protocol, minimizes the preamble by combining preamble sampling and scheduling techniques; however, it does not prevent energy loss due to overhearing; in addition, due to its synchronization procedure, it results in increased contention and delay. In this paper, we present an energy efficient MAC protocol for WSNs that avoids overhearing and reduces contention and delay by asynchronously scheduling the wakeup time of neighboring nodes. We provide an energy consumption analysis for multi-hop networks. To validate our design and analysis, we implement the proposed scheme in TinyOS. Experimental results show that AS-MAC considerably reduces energy consumption, packet loss and delay when compared with existing energy efficient MAC protocols.     

基于ZigBee的低功耗无线传感器网络改进协议

如何降低无线传感器网络(WSNs)节点的能耗来延长网络寿命是非常重要的,无线网路的性能主要取决于MAC协议,若要降低节点能耗,合理的设计与改进MAC协议就成为一个关键性问题.主要介绍了无线传感器网络中的ZigBee技术发展与应用,针对相关能耗问题,将延迟测量时间同步(DMTS)算法融入到ZigBee网络中,同时引入了基于S-MAC协议机制的周期性侦听/睡眠、碰撞避免等措施对协议进行改进,通过仿真与基本协议进行比较.仿真结果表明:改进的协议能够有效降低网络节点能耗.     

BSC-MAC: Energy efficiency in wireless sensor networks with base station control

Wireless sensor networks (WSNs) are now used in many areas and the interest in this technology continues to increase. Due to the small structure of the processor, the memory of the sensor nodes forming the wireless sensor networks, and as they are operated by a battery, the most important problem appears to be the energy issue. The battery depletion of the sensor nodes randomly deployed in critical areas may negatively interfere with part or all of the network communication and may cause the life of the entire network to terminate. Therefore, many studies have been conducted in the field of energy efficiency. In this study, Base Station Controlled MAC (BSC-MAC), which is a new design of MAC, is recommended. The BSC-MAC protocol presents an adaptive approach for energy efficiency. It determines the nodes on the network as root and source nodes and manages a sleep schedule according to these structures. The simulation of the BSC-MAC protocol was performed with ns-2 and compared to similar protocols, such as adaptive energy efficient MAC (AEEMAC), pattern MAC (P-MAC), and sensor MAC (S-MAC).     

An energy-efficient,transport-controlled MAC protocol for wireless sensor networks

In wireless sensor networks (WSNs), one major cause of wasted energy is that the wireless network interface is always on to accept possible traffic. Many medium access control (MAC) protocols therefore adopted a periodic listen-and-sleep scheme to save energy, at sacrifice of end-to-end latency and throughput. Another cause is packet dropping due to network congestion, necessitating a lightweight transport protocol for WSNs. In this paper, we suggest a transport-controlled MAC protocol (TC-MAC) that combines the transport protocol into the MAC protocol with the aims of achieving high performance as well as energy efficiency in multi-hop forwarding. Although TC-MAC also works through a periodic listen-and-sleep scheme, it lowers end-to-end latency by reserving data forwarding schedules across multi-hop nodes during the listen period and by forwarding data during the sleep period, all while increasing throughput by piggybacking the subsequent data forwarding schedule on current data transmissions and forwarding data consecutively. In addition, TC-MAC gives a fairness-aware lightweight transport control mechanism based on benefits of using the MAC-layer information. The results show that TC-MAC performs as well as an 802.11-like MAC in end-to-end latency and throughput, and is more efficient than S-MAC in energy consumption, with the additional advantage of supporting fairness-aware congestion control.     

无线传感器网络中一种竞争窗口自适应MAC协议

媒体访问控制(MAC)协议是保证无线传感器网络(WSNs)高效通信的关键网络协议之一。MAC层协议设计的是否合理将严重影响网络的性能。介绍了现有MAC协议分类和主要MAC协议。分析了WSNs中典型的S-MAC协议,针对S-MAC协议在载波侦听时采用固定竞争窗口的弊端,提出了一种新型的能够根据流量变化对竞争窗口进行动态调整的新的MAC协议ASMAC,利用NS2对ASMAC进行了仿真,证明了新的ASMAC不仅能够显著地提高吞吐量,降低时延,还能有效提高能量效率,在提高网络性能的同时达到节能的目的。     

睡眠调度技术在无线传感器网络的MAC层协议中的应用分析

无线传感器网络是由大量低成本的传感器节点构成的自组织网络。因为工作环境和成本因素,传感器节点通常不会更换电池,能量十分有限。节能是传感器网络中媒体访问控制（MAC）协议设计的首要问题,节点睡眠调度机制是节能的一个有效手段。文章介绍和分析了S-MAC,T-MAC,D-MAC中的睡眠调度机制的特点,并对未来研究方向提出了展望。     

Determining node duty cycle using Q-learning and linear regression for WSN

Wireless sensor network(WSN)is effective for monitoring the target environment,which consists of a large number of sensor nodes of limited energy.An efficient medium access control(MAC)protocol is thus imperative to maximize the energy efficiency and performance of WSN.The most existing MAC protocols are based on the scheduling of sleep and active period of the nodes,and do not consider the relationship between the load condition and performance.In this paper a novel scheme is proposed to properly determine the duty cycle of the WSN nodes according to the load,which employs the Q-leaming technique and function approximation with linear regression.This allows low-latency energy-efficient scheduling for a wide range of traffic conditions,and effectively overcomes the limitation of Q-learning with the problem of continuous state-action space.NS3 simulation reveals that the proposed scheme significantly improves the throughput,latency,and energy efficiency compared to the existing fully active scheme and S-MAC.     

基于竞争与TDMA的低时延无线传感器网络MAC协议

针对经典无线传感器网络（WSNs） S-MAC协议的累积睡眠延迟问题,提出了一种基于竞争与时分复用（TDMA）方式混合的低时延LH-MAC协议.LH-MAC根据包的传输跳数,提供不同优先级的接入服务,使已完成多跳传输的包以更大的概率接入信道,实现较远节点的低时延传输目标.仿真比较S-MAC与LH-MAC的平均延迟和能耗,表明LH-MAC在保持能量高效前提下,有效降低了端到端时延.     

一种能量有效的移动无线传感器网络MAC协议

基于S-MAC协议改进,利用虚拟簇之间边界节点的调度信息,采用能量有效的二次监听和灵活的调度自适应两个主要方法,设计一种能量有效的移动无线传感器网络MAC协议(EM-MAC),能实现移动节点更有效的更快速的睡眠——唤醒调度自适应。仿真结果表明该协议用于移动无线传感器网络,在能耗、延迟等性能方面有较好提高。     

无线传感器网络MAC协议的设计研究

媒体访问控制(MAC)协议是无线传感器网络协议的重要组成部分,它的性能好坏直接关系到无线信道的利用效率和整个网络的性能。介绍了无线传感器网络MAC协议设计的主要问题,根据设计指标的不同对无线传感器网络MAC协议进行了分类,并在此基础上,分析研究了几种典型的无线传感器网络MAC协议采用的机制和方法。     

C3: an energy-efficient protocol for coverage,connectivity and communication in WSNs

The lower layer of ubiquitous and pervasive systems consists of wireless ad hoc and sensor networks. In wireless sensor networks (WSNs), sensors consume most of their energy in data transmission and idle listening. Hence, efficient usage of energy can be ensured by improved protocols for topology control (i.e., coverage and connectivity), sleep scheduling, communication, and aggregation and compression of data. Though several protocols have been proposed for this purpose, they are not energy-efficient. We propose an integrated and energy-efficient protocol for Coverage, Connectivity, and Communication (C3) in WSNs. The C3 protocol uses received signal strength indicator to divide the network into virtual rings, defines clusters with clusterheads more probably at alternating rings, defines dings that are rings inside a cluster and uses triangular tessellation to identify redundant nodes, and communicates data to sink through clusterheads and gateways. The proposed protocol strives for near-optimal deployment, load balancing, and energy-efficient communication. Simulation results show that the C3 protocol ensures partial coverage of more than 90 % of the total deployment area, ensures one connected network, and facilitates energy-efficient communication while expending only one-fourth of the energy compared to other related protocols such as the coverage and connectivity protocol, and the layered diffusion-based coverage control.     

基于时分复用的无线传感器网络MAC协议研究

对近年来无线传感器网络(W SNs)的基于时分复用(TDMA)的媒质访问控制(MAC)协议的最新研究进展进行了讨论和综述,描述了设计W SNs的MAC协议应该考虑的问题,详细论述了传感器网络的MAC协议的能量有效性问题,着重对一些具有代表性的基于TDMA的MAC协议进行对比、分析,并在此基础上提出了将来设计这类MAC协议的方向和建议。     

无线传感器网络MAC层能耗与时延的权衡

无线传感器网络节点设计的最重要约束之一就是要求低能耗,这与传统网络依赖持续的能源供应而致力于提供尽可能高的服务质量截然不同.研究了一个结合无线传感器网络的能耗特性而提出的MAC协议S-MAC协议,并在对802.11MAC、S-MAC中的能耗状态与时延特征进行理论和数学分析的基础上,通过仿真实验得出了在模拟网络环境中802.11MAC和S-MAC的能耗和平均时延,S-MAC协议中引入节点周期性睡眠、冲突串音避免和消息传递等新技术,以牺牲时延为代价换取高效的能量利用,提供了一种高效可扩展的在能耗和时延之间进行权衡的方案.     

一种无线传感器网络MAC协议优化算法

在无线传感器网络中,各节点采集的信息以多跳的方式传送到汇聚点.从各节点到汇聚点形成一棵以汇聚点为根的传输树.文中在对无线传感器网络传输特点分析的基础上,剖析了基于CSMA/CA(载波多路监听/冲突避免)的MAC协议在树状结构无线传感器网络中的弊端,提出了一种基于CSMA/CA的MAC协议优化算法.算法基于节点在传输树中的位置信息调整其MAC信道接入分配,将CSMA/CA采用的各节点均等竞争信道的方法优化为各节点依据在传输树中的位置情况竞争信道的方式,这一优化提高了节点公平性,使MAC信道接入分配与树状结构的无线传感器网络传输特点相契合,解决了基于CSMA/CA的MAC协议与树状结构无线传感器网络不匹配的问题,从而减少了信道资源浪费,提高了网络传输效率,降低了能耗.实验结果表明该算法在网络丢包率、吞吐量和能耗方面的性能均有较大改进.     

一种多信道混合方式的无线传感器网络MAC协议

为了提高无线传感器网络的吞吐量,降低时延,本文设计了一种多信道MAC协议——MCHMAC。它采用调度和竞争访问机制相结的混合方式来传输信息,通过动态调整节点的活跃与睡眠状态的时长来节省能量。MCHMAC使用信道状态估计算法对信道进行评估,利用信道调度表来为节点调度状态最优的信道。仿真实验结果证明,本协议提高了吞吐量,降低了网络时延。     

基于数据重排序的无线传感器网络低延时节能MAC协议

节能,是无线传感器网络最关注的问题之一.让节点进行周期性的侦听与睡眠是一种常用的节能机制.但是,这种节能机制在数据报的传输过程中会引入较长的端到端延时,而且延时与整个周期的长度成正比.提出了一种应用于无线传感器网络的低延时的节能MAC协议:RLL-MAC.该协议在S-MAC/AL(S-MAC with Adaptive Listening)的基础上,增加了数据报重排序机制,即能够根据各个节点工作周期的时序关系,动态的调整数据报的发送次序,从而减少数据报的端到端延迟.通过理论分析和仿真实验表明,与S-MAC/AL相比,RLL-MAC在保持低能耗的同时,极大的降低了端到端延迟.     

基于跨层竞争的同步MAC协议研究

在无线传感器网络(WSNs)中,基于跨层竞争的同步媒体接入控制(MAC)在一周期内可安排多个数据包的多跳传输,传统的协议在同一个数据窗口传输请求数据包和确认数据包,降低了数据窗口的多跳流量的建立,也降低了在多跳场景中的数据包传输率和传输时延性能.本文提出了基于新的基于跨层竞争的同步MAC(CLC-MAC)协议,CLC-MAC协议引用新的周期结构,且其包含两个独立窗口,并由该窗口分别传输数据请求包和确认包,即请求包在数据窗口传输,而确认包在休眠窗口传输.实验数据表明:与先锋路由帧MAC(PRMAC)协议相比,CLC-MAC协议的端到端传输时延和数据包传输率的性能均得到了提高.     

带冲突避免和流量自适应的低功耗侦听MAC协议

为提升无线传感器网络在能耗、时延以及动态适应负载方面的综合性能, 对几种典型MAC协议进行了分析, 提出了一种带冲突避免和流量自适应的LCT-MAC协议。在该协议中, 长前导码被划分为多个小前导码, 并嵌入目的节点地址信息, 避免了串音; 节点可以根据网络流量调整睡眠周期, 减少了时延; 在重负载时, 节点能基于优先级信息选择退避时长, 避免冲突。仿真结果表明, 与S-MAC协议和LPL协议相比, LCT-MAC协议降低了传输时延, 并减少了全网能耗和数据包碰撞次数, 具有优良的综合性能。     

基于任务组合的无线传感器网络MAC协议框架

基于无线传感器网络WSN(Wireless Sensor Network)语义互连思想,讨论了面向应用的WSN任务组合的基本概念、任务关系及任务组合递归算法。将任务组合方法与现行WSN一般性MAC技术相结合,提出了基于任务组合的通用的WSNMAC框架。将该框架应用于具有代表性的WSN MAC中,具体分析了IEEE 802.11MAC和S-MAC在该框架中的实现方式。网络仿真结果显示,基于语义互连采用任务组合方式的MAC协议框架,能有效地改进一般MAC的能耗特性及时延特性,尤其是对于多信息采集的WSN。