基于Zigbee簇树路由的链路寻址方式改进

IEEE 802.15.4/Zigbee规范因其低速率,低功耗和低成本的特征而非常适合作为WSN的无线通信技术.使用该技术构建簇树型WSN时,网络性能受哪些因素的影响,影响程度如何都是值得研究的问题.本文通过一个自建的簇树型WSN仿真模型,研究了中心协调器位置对节点接入成功率的影响;传感器节点发包速率和信号发射功率对吞吐量和传包率的影响,并对簇树形路由的寻址方式进行了改进,将跨点寻址应用在路由方式中,取得了良好的网络效果.     

Flexible IEEE 802.15.4 deadline-aware scheduling for DPCSs using priority-based CSMA-CA

The IEEE 802.15.4 protocol offers great potential in several application fields, such as industrial Wireless Sensor Networks (WSNs). An industrial automation cell (field level) is characterized mostly by periodic traffic flows. Using the IEEE 802.15.4 protocol, it is necessary to manage Guaranteed Time Slots (GTSs) allocation and at the same time ensure adequate performance both to other periodic traffic flows and network management/control flows. For these reasons, this paper shows a flexible approach in order to improve GTSs assignment and medium access performance. Analytical results are shown in order to demonstrate benefits introduced by deadline-aware algorithm (for guaranteed access to reserved slots) and CSMA-CA-priority based (for latencies reduction during medium access attempts). Otherwise, obtained results show that the proposed technique improves the number of deadlines met and the probability to find the channel free for transmissions.     

WSN中利用贝叶斯博弈的数据传递策略

在无线传感器网络中,数据的传递策略对网络的能量损耗具有重要的影响,为此,提出了一个基于贝叶斯博弈的数据传递模型。在该模型中网络节点为了获取最大的收益,在考虑自身能量水平的基础上,适当的调整发送/转发的数据量。当节点发送/转发的数据满足一定条件时,网络存在均衡状态。仿真结果表明,该基于博弈论的数据传递策略在均衡状态下能够明显降低能量损耗,延长网络的使用寿命。     

Intelligent antenna selection decision in IEEE 802.15.4 wireless sensor networks: An experimental analysis

The goal of this paper is to study the feasibility of making intelligent antenna selection decision in IEEE 802.15.4 Wireless Sensor Networks (WSNs). This study provides us the basis to design and implement software defined intelligent antenna switching capability to wireless sensor nodes based on Received Signal Strength Indicator (RSSI) link quality metric. First, we discuss the results of our newly designed radio module (Inverted-F Antenna) for 2.4 GHz bandwidth (WSNs). Second, we propose an intelligent antenna selection strategy to exploit antenna diversity. Third, we propose the prototype of our diversity antenna for the TelosB mote and the intelligent switch design. Finally, we compare the performance of the built-in TelosB antenna with our proposed external antenna in both laboratory and realistic environments. Experimental results confirm the gain of 6–10 dB of the proposed radio module over the built-in radio module of the TelosB motes.     

Generic Markov model of the contention access period of IEEE 802.15.4 MAC layer

The IEEE-802.15.4 standard is poised to become the global standard for low data rate, low energy consumption Wireless Sensor Networks. By assigning the same sets of contention access parameters for all data frames and nodes, the Contention Access Period (CAP) of the slotted IEEE-802.15.4 currently provides an even channel access functionality and no service differentiation. However, some applications may require service differentiation and traffic prioritization support to accommodate high-priority traffic (e.g., alarms). In order to simulate a scenario in which different sets of access parameters for different node classes can be configured, this paper develops a Markov-chain-based model of the CAP of the IEEE-802.15.4-MAC. Our Markov model can be used to evaluate the impact of mixing node classes in important factors like the throughput, energy consumption, probability of delivery and the packet latency. The model has been used to provide traffic differentiation in a high saturation scenario in which a set of nodes can be configured to increase 76% the probability of sending a packet and reduce 58% latency, with a 69% energy penalty, in comparison with a standard scenario. The accuracy of the Markov model is validated by extensive ns-2 simulations.     

一种IEEE 802.11接入机制的新退避算法

无线传感器网络采用类似开放式系统互联模型的协议栈,作为第一个完全针对无线传感网络设计的MAC协议,S-MAC采用了IEEE802.11DCF的接入机制。本文在分析了IEEE802.11协议的二进制指数退避算法(BEB),以及倍数增线性减退避算法(MILD)后,提出了一种基于网络性能指标的新退避算法。新算法将无线信道中的时隙利用率映射网络性能指标传输概率,对网络中连续两次发送的时隙利用率进行平均滤波处理,改变重传节点的发送优先级,来调整节点在竞争使用窗口的退避值,以达到有效减少网络的碰撞、提高无线信道的使用效率和网络吞吐率的目的。仿真结果表明,新退避算法能更准确地估计网络当前的竞争状态,有效地提高了网络吞吐率,获得较好的网络性能。     

无线传感器网MAC协议能耗控制性能研究

为研究无线传感器网对能耗的要求,提出一种无线传感器网媒体接入控制协议,对应用场景进行抽象,基于OPNET构建无线传感器网仿真平台,测试不同应用场景下各种媒体接入控制协议的能耗和延时性能,实验结果表明,任何一类媒体接入控制协议均能在不同应用场景中提供较好的性能,但不是最优的。     

一种基于能量感知无线传感器网络多路径路由机制

目前,无线传感器网络在智能环境检测,灾难控制,战场侦察,安全监视方面取得了日益广泛的应用,引起人们日益关注,在分析无线传感器网络能量消耗特征的基础上,基于Markov模型提出了无线传感器网络节点能量消耗模型,改进了无线传感器网络多路径路由协议。仿真结果表明,与传统的多路径路由机制相比,能够有效地降低无线传感器网络节点能量消耗,提高网络生存时间。     

体域医学传感器网络的设计及其QoS性能分析

提出医学无线传感器网络（MWSNs）的三层体系结构,并重点分析体域医学传感器网络的组成结构和网络传输需求。设计了基于IEEE 802.15.4无线个域网协议的体域医学传感器网络（BA-MWSN）,其拓扑结构采用星型,MAC采用时隙CSMA/CA机制。通过网络仿真评估了该BA-MWSN的QoS性能,分析表明：该网络能满足体域MWSNs的网络传输要求;设置合理的节点数量、网络负载和使用长帧可以获得较高的网络利用率和可靠性。     

Energy efficient and QoS based routing protocol for wireless sensor networks

The increasing demand for real-time applications in Wireless Sensor Networks (WSNs) has made the Quality of Service (QoS) based communication protocols an interesting and hot research topic. Satisfying Quality of Service (QoS) requirements (e.g. bandwidth and delay constraints) for the different QoS based applications of WSNs raises significant challenges. More precisely, the networking protocols need to cope up with energy constraints, while providing precise QoS guarantee. Therefore, enabling QoS applications in sensor networks requires energy and QoS awareness in different layers of the protocol stack. In many of these applications (such as multimedia applications, or real-time and mission critical applications), the network traffic is mixed of delay sensitive and delay tolerant traffic. Hence, QoS routing becomes an important issue. In this paper, we propose an Energy Efficient and QoS aware multipath routing protocol (abbreviated shortly as EQSR) that maximizes the network lifetime through balancing energy consumption across multiple nodes, uses the concept of service differentiation to allow delay sensitive traffic to reach the sink node within an acceptable delay, reduces the end to end delay through spreading out the traffic across multiple paths, and increases the throughput through introducing data redundancy. EQSR uses the residual energy, node available buffer size, and Signal-to-Noise Ratio (SNR) to predict the best next hop through the paths construction phase. Based on the concept of service differentiation, EQSR protocol employs a queuing model to handle both real-time and non-real-time traffic.     

无线传感器网络最小能量簇群构造策略

尽可能延长无线传感器网络（WSNs）的生命周期是设计和部署网络所面临的最大挑战之一。由于节点配备的能量有限，采用分簇方式组织节点可以极大地降低节点与Sink节点通信的能耗。簇群成员节点和簇头的通信方式与簇群的拓扑结构决定整个簇群的能量消耗速度。文中分析了簇群节点采用Multi-hop通信方式时，节点通过中继节点与簇头通信时能量消耗的模型，然后在选择链路的最优跳数的基础上，提出建立最小能量中继链路的方法，实现通信能耗的最小化。对WSNs的设计和实施具有一定的指导意义。     

基于6LoWPAN的嵌入式多网关系统设计与实现

6LoWPAN是一种在IEEE802.15.4标准基础上IP化实现无线传感器网络的技术。在现有单目的导向的有向无环图（DODAG）环路由协议标准下,存在围绕单边界路由器的网络拥塞和能耗问题。设计了一种嵌入式6LoWPAN多网关协议和系统,嵌入式网关节点具备双模通信功能,可实现无线传感网（WSN）和固定IPv6网络的物理连接,双模网关通过固网建立与6LoWPAN根边界路由器之间的IP隧道来实现上下行路由。通过对现有6LoWPAN协议标准的补充和优化,使双模节点具有网内和网际路由能力,从而实现多网关架构和多径路由功能。优化的多点互通拓扑位置和流量分担算法实现上下行链路的有效负载平衡,也减小了节点多跳路由能耗。通过对多网关平台进行实验测试,并与单网关系统对比测试,结果表明该方案不仅实现了6LoWPAN在以太网的多点接入,降低了网络内数据传输时延和丢包率,并且提升了网络整体吞吐量。     

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。     

改进的基于统计学的滑动窗口无参数的累积和算法

为解决IEEE802.15.4无线传感器网络(WSN)中节点自私行为的检测问题,将最低检测延迟作为决策目标,提出了一种改进的基于统计学的滑动窗口无参数的累积和(SWN-CUSUM)算法。算法通过跟踪来自数据包两次成功传输之间的延迟特征序列,以此来判断无线传感器网络中的节点是否存在自私行为。最后通过NS2仿真工具验证算法的有效性。研究结果表明：改进的算法不仅弱化了阈值对算法性能的影响,还缩小了用于检测自私行为的滑动窗口大小,同时所提算法相对于原SWN-CUSUM算法在计算量及检测延迟上均有改善,证明改进的算法可以有效、快速地检测IEEE802.15.4无线传感器网络中的节点自私行为。     

无线传感器网络中基于关联度的多查询优化

无线传感器网络是一种以数据为中心的网络,用户通过基站向网络提出查询请求获取所需数据。如何通过多查询的优化来减少传感器节点的能耗以延长网络生命期是无线传感器网络中需要解决的关键问题之一。提出了基于关联度的多查询优化算法,其基本思想是节点通过节点与候选父亲节点之间的关联度来选择父节点,从而被相同查询覆盖的节点聚集成一个组,多个查询间共享组中节点的数据,在网络中对查询数据进行有效的融合,充分减少了网络的数据传输量,延长了网络的生命期。理论分析和模拟实验表明该算法可以充分减少数据传输量,从而达到节能的目的。     

An approach to implement data fusion techniques in wireless sensor networks using genetic machine learning algorithms

Wireless Sensor Networks (WSNs) can be used to monitor hazardous and inaccessible areas. In these situations, the power supply (e.g. battery) of each node cannot be easily replaced. One solution to deal with the limited capacity of current power supplies is to deploy a large number of sensor nodes, since the lifetime and dependability of the network will increase through cooperation among nodes. Applications on WSN may also have other concerns, such as meeting temporal deadlines on message transmissions and maximizing the quality of information. Data fusion is a well-known technique that can be useful for the enhancement of data quality and for the maximization of WSN lifetime. In this paper, we propose an approach that allows the implementation of parallel data fusion techniques in IEEE 802.15.4 networks. One of the main advantages of the proposed approach is that it enables a trade-off between different user-defined metrics through the use of a genetic machine learning algorithm. Simulations and field experiments performed in different communication scenarios highlight significant improvements when compared with, for instance, the Gur Game approach or the implementation of conventional periodic communication techniques over IEEE 802.15.4 networks.     

基于能量优化的无线传感器网络分簇路由算法研究

无线传感器网络的路由协议设计要同时关注单个节点的能耗及整个网络能量的均衡消耗.分簇算法能有效解决节点能耗受限与不同节点能量开销不平衡问题.在分析了传统分簇路由LEACH(low energy adaptive clustering hierarchy)协议中选择簇头算法不足和当前一些典型基于LEACH思想的路由改进算法...     

无线传感器网络基于议价解的合作策略

针对无线传感器网络（WSN）的合作多样性问题,对结合节点能耗和吞吐量的对称合作模式进行了讨论。基于Raiffa-Kalai-Smorodinsky议价解（RBS）,将对称合作问题转换成议价问题,提出了一种提高网络传输效率的WSN对称合作策略。分析了由[n]传感器节点和一个sink 组成的对称合作模型,并在此基础上,讨论了RBS最优带宽分配策略的实现过程。仿真结果表明,该对称合作策略可以大大提高传感器节点的传输效率。     

SMAC multi-hop mesh routing protocol using IEEE 802.15.4

This paper discusses some aspects related to Wireless Sensor Networks over the IEEE 802.15.4 standard, and proposes, for the very first time, a mesh network topology with geographic routing integrated to the open Freescale protocol (SMAC - Simple Medium Access Control). For this is proposed the SMAC routing protocol. Before this work the SMAC protocol was suitable to perform one hop communications only. However, with the developed mechanisms, it is possible to use multi-hop communication. Performance results from the implemented protocol are presented and analyzed in order to define important requirements for wireless sensor networks, such as robustness, self-healing property and low latency.     

基于三链混合遗传算法的WSNs 中 Sink节点布局优化

对无线传感器网络的设计和布局中,多Sink 节点的布局是其拓扑设计的关键,对网络通信的能量控制至关重 要。本文通过分析其Sink 节点布局模型,提出一种改进的三链混合遗传算法对Sink 节点布局求取最优解。实验表明,三链混 合遗传算法在针对Sink 节点的布局算法中相对于枚举算法,具有较优解,并且算法效率高,可降低无线传感器网络的能耗,改 善网络性能。