EasiCC:一种保证带宽公平性的传感器网络拥塞控制机制

实用的传感器网络拥塞控制方案不仅需要满足多项网络性能指标,而且必须控制开销很小,提出了一种满足上述要求的拥塞控制机制EasiCC(EasiNet congestion control mechanism).在EasiCC中,数据流源节点将数据报文按比例划分到各优先等级中,各网络节点根据网络拥塞程度动态地、同步地调整报文过滤标准,结合报文过滤标准和报文优先级来调节网络流量,保证了无线信道带宽分配上的公平性;将网络准入控制和队列丢包手段相结合来调整网络流量,保证了网络综合性能指标.EasiCC控制开销很少,已在实际传感器网络平台中实现.模拟验证和实验测试结果显示,EasiCC能够公平地为各数据流分配发报速度和网络带宽,并且在报文传输成功率、传输延迟等性能指标上均有良好的表现.     

A proportional fairness scheduling for wireless sensor networks

This paper describes a packet scheduling algorithm for wireless sensor networks (WSNs) that meets the proportional fairness principle. Based on the weighted round-robin strategy, the proposed scheduling algorithm allocates a different service quota to different traffic according to the average packet arrival rate. This guarantees proportional fairness in terms of the average packet delivery delay and the average packet loss ratio. Since the scheduling algorithm does not perform high-load operations such as time stamping and sorting, it can be implemented easily and is suitable for resource-limited WSNs. The proposed scheduling algorithm is tested in a WSN and is found to guarantee the proportional fairness of the average packet delivery delay when this is used as the performance metric, and to realize proportional fairness in the average packet loss ratio when all the queues are overflowing and the average packet loss ratio is used as the performance metric.     

An accurate performance model for network-on-chip and multicomputer interconnection networks

In this paper, we present a mathematical background for a new approach for performances modeling of interconnection networks, based on analyzing the packet blocking and waiting time spent in each channel passing through all possible paths in the channel dependency graph. We have proposed a new, simple and very accurate analytical model for deterministic routing in wormhole networks, which is general in terms of the network topology and traffic distribution. An accurate calculation of the variance of the service time has been developed, which overcomes the rough approximation used, as a rule, in the existing models. The model supports two-dimensional mesh topologies, widely used in network-on-chip architectures, and multidimensional topologies, popular in multicomputer architectures. It is applicable even for irregular topologies and arbitrary application-specific traffic. Results obtained through simulation show that the model achieves a high degree of accuracy.     

Enhanced Security with Improved Defensive Routing Mechanism in Wireless Sensor Networks

In recent scenario of Wireless Sensor Networks (WSNs), there are many application developed for handling sensitive and private data such as military information, surveillance data, tracking, etc. Hence, the sensor nodes of WSNs are distributed in an intimidating region, which is non-rigid to attacks. The recent research domains of WSN deal with models to handle the WSN communications against malicious attacks and threats. In traditional models, the solution has been made for defending the networks, only to specific attacks. However, in real-time applications, the kind of attack that is launched by the adversary is not known. Additionally, on developing a security mechanism for WSN, the resource constraints of sensor nodes are also to be considered. With that note, this paper presents an Enhanced Security Model with Improved Defensive Routing Mechanism (IDRM) for defending the sensor network from various attacks. Moreover, for efficient model design, the work includes the part of feature evaluation of some general attacks of WSNs. The IDRM also includes determination of optimal secure paths and Node security for secure routing operations. The performance of the proposed model is evaluated with respect to several factors; it is found that the model has achieved better security levels and is efficient than other existing models in WSN communications. It is proven that the proposed IDRM produces 74% of PDR in average and a minimized packet drop of 38% when comparing with the existing works.     

Energy-aware node placement,topology control and MAC scheduling for wireless sensor networks

In the WSNs, the nodes closer to the sink node have heavier traffic load for packet forwarding because they do not only collect data within their sensing range but also relay data for nodes further away. The unbalanced power consumption among sensor nodes may cause network partition. This paper proposes efficient node placement, topology control, and MAC scheduling protocols to prolong the sensor network lifetime, balance the power consumption of sensor nodes, and avoid collision. Firstly, a virtual tree topology is constructed based on Grid-based WSNs. Then two node-placement techniques, namely Distance-based and Density-based deployment schemes, are proposed to balance the power consumption of sensor nodes. Finally, a collision-free MAC scheduling protocol is proposed to prevent the packet transmissions from collision. In addition, extension of the proposed protocols are made from a Grid-based WSN to a randomly deployed WSN, enabling the developed energy-balanced schemes to be generally applied to randomly deployed WSNs. Simulation results reveal that the developed protocols can efficiently balance each sensor node’s power consumption and prolong the network lifetime in both Grid-based and randomly deployed WSNs.     

基于HJB方程的无线传感器网络系统Minimax控制器设计

针对工业环境下无线传感器网络系统在受到外部较大干扰时的系统稳定性问题,提出Hamilton-JacobiBellman (HJB)方程与Minimax控制相结合的方法.首先,针对无线传感器网络在复杂工况环境下出现的网络时延和连续丢包有界的情况,给出具有时延和丢包的无线传感器网络系统模型;然后,在Minimax性能指标函数下,利用HJB方程设计系统的Minimax最优控制器,进一步通过检验函数得出有关最大干扰的表达形式,从而推导出系统稳定的充分条件;最后,通过数值算例和仿真验证系统在突发较大干扰时采用所提方法的可行性和有效性.     

井下无线传感器网络AODV和DSDV协议的仿真对比

通过分析当前煤矿安全监测无线传感器网络的路由特点及其对应的掘进工作面典型的系统方案,比较当前无线传感网络中比较经典的AODV和DSDV路由协议,为了考察这两种路由协议在矿井下的性能,使用NS2网络仿真软件的Shadowing模式,选取包成功投递端到端的平均延时、包成功投递率、路由协议负载这三个衡量指标对AODV与DSDV路由协议进行了性能评估,研究结果表明在节点相对少的掘进巷道场景下DSDV协议表现出较好的特点和很好的鲁棒性,为满足井下实时监测网络的应用需求提供一种方案.     

一种基于蚁群优化的WSN拥塞控制算法*

针对无线传感器网络中由于拥塞引起的丢包和能量过度消耗等问题,提出了一种基于蚁群优化的拥塞控制算法以减轻WSN中的拥塞和改进网络性能。该算法充分考虑了给定时刻WSN的拥塞状况,分成三个阶段在源节点和sink节点间寻找一条最佳的路径,并及时地消除拥塞。仿真实验结果表明,该算法在网络吞吐量、丢包率、时延和能耗方面具有较好的综合网络性能。     

SEEM: Secure and energy-efficient multipath routing protocol for wireless sensor networks

A Wireless Sensor Network (WSN) is a collection of wireless sensor nodes forming a temporary network without the aid of any established infrastructure or centralized administration. In such an environment, due to the limited range of each node’s wireless transmissions, it may be necessary for one sensor node to ask for the aid of other sensor nodes in forwarding a packet to its destination, usually the base station. One important issue when designing wireless sensor network is the routing protocol that makes the best use of the severely limited resource presented by WSN, especially the energy limitation. Another import factor required attention from researchers is providing as much security to the application as possible. The proposed routing protocols in the literature focus either only on increasing lifetime of network or only on addressing security issues while consuming much power. None of them combine solutions to the two challenges. In this paper, we propose a new routing protocol called SEEM: Secure and Energy-Efficient multipath Routing protocol. SEEM uses multipath alternately as the path for communicating between two nodes thus prolongs the lifetime of the network. On the other hand, SEEM is effectively resistive to some specific attacks that have the character of pulling all traffic through the malicious nodes by advertising an attractive route to the destination. The performance of our protocol is compared to the Directed Diffusion protocol. Simulation results show that our protocol surpasses the Directed Diffusion protocol in terms of throughput, control overhead and network lifetime.     

WSN中基于中继选择的DH-MSMR-CARQ时延与吞吐量分析

为提高无线传感器网络（WSN）的时延和吞吐量性能,提出了一种两跳多源多中继协同自动重传请求（DH-MSMR-CARQ）协议。建立最大比合并（MRC）下两种不同中继选择的DH-MSMR-CARQ协议Markov链模型,分别给出状态空间。基于截短,由各自的平均分组差错率和状态转移概率矩阵推导协议的平均传输时延和吞吐量解析表达式。数值模拟结果表明,源节点数、分组长度及最佳中继节点到目的节点的分组差错率是影响平均传输时延的关键因素,采用第一种中继选择方式具有更高的吞吐量。另外,在非极端恶劣信道环境下（源节点到中继节点的分组差错率小于0.8）,DH-MSMR-CARQ协议比可直达的SSSR-CARQ、MSSR-CARQ和MSMR-CARQ协议具有更高的吞吐量。     

一种自适应占空比的WSN MAC协议

PW-MAC 协议中发送者通过预测接收者的醒来时间来最小化传感器节点的能量消耗,但在无陑传感器网络中, PW-MAC协议不能适应大幅流量的变化。为此,提出一种动态调整传感器节点占空比的MAC协议,该协议采用传感器的占空比,根据流量的变化进行动态调整。仿真结果证明,与 PW-MAC 协议陒比,该协议数据包传输延时减少30%,数据包投递率提高35%。     

基于网络效用最大化与冲突避免的无线传感器网络MAC协议

针对周期汇报型无线传感器网络(WSN)中的无线信号冲突和能量利用效率问题,提出了一种基于网络效用最大化与冲突避免的媒体访问控制(UM-MAC)协议。该协议基于时分多路复用(TDMA)调度机制,将效用模型引入无冲突的节点工作时隙分配过程中,把链路可靠性、网络能耗归纳到一个统一的效用优化框架中;进而提出了一个启发式算法,使网络能够快速找到一个基于网络效用最大化与冲突避免的节点工作时隙调度方案。将UM-MAC协议与S-MAC协议和冲突避免MAC(CA-MAC)协议进行比较,在不同节点数量的网络环境中,UM-MAC获得的网络效用较大,平均数据包成功发送率较高,生命周期介于S-MAC与CA-MAC之间,在不同的网络负载下所有节点发数据包到汇聚节点的平均时延有所增加。仿真实验结果表明:UM-MAC协议较好地解决了冲突干扰问题,提高了网络的数据包成功发送率和能量利用效率等性能;在低网络负载时,TDMA类协议的性能并不比竞争类协议好。     

无线传感器网络权衡生存时间与数据分组跳数的分流路由算法*

无线传感器网络的节点大多采用电池供电.因而节能对无线传感器网络就显得至关重要.该文提出一种能耗感知的优化网络生存时间的路由算法,称之为分流路由算法(DTRA,Diffluent Traffic Routing Algorithm).DTRA算法采用一个优化模型以优化每个节点发出的数据比例,从而达到权衡网络生存时间和数据分组跳数.此外,采用一个简单的遗传算法求解该优化问题.仿真结果表明:DTRA算法能显著地提高网络的生存时间,同时将数据分组平均跳数保持在一个较低的水平;在网络生存时间上,DTRA算法比一些已有的知名算法更优.     

基于ARMA的WSN流量预测模型

无线传感器网络(WSN)的流量预测研究对WSN管理有重要的意义。提出基于ARMA的网络流量实时在线预测模型,并对该预测模型进行了推导分析;在仿真平台中实现了算法,并对仿真结果进行了分析和统计,仿真结果显示预测模型有效提高了无线传感器网络流量的预测精度。     

基于IPv6的无线传感器网络接入设计*

无线传感器网络(WSN)与现有网络基础结合是WSN研究中必须解决的技术问题之一。在IPv6协议下,提出了一种大规模无线传感器网络接入国际互联网方式。本接入方式以数据应用为中心,按地理位置为无线传感器网络映射IPv6地址,由此设计了一种基于地理位置信息的顺时针逐格CGRP路由协议,并通过仿真实验分析协议的稳定性和路由分组传输成功率,最后阐述了以网关为路由接口的无线传感器网络与Internet通信机制。该接入方式既能根据IP对无线传感器网络寻址,又能降低无线传感器网络全IP化带来的高额开销,符合无线传感器应用     

无线传感器网络TCP性能的改善机制

在无线传感器网络中,节点分布过于密集或大量数据流的突发将造成拥塞,导致报文丢失,引起吞吐量下降和能量浪费。该文提出一种新的拥塞控制机制PTCP,通过分段调整慢启动阶段的TCP窗口增长速度控制拥塞。仿真结果证明,该机制有效解决了传感器网络中的拥塞控制问题,提高了无线传感器网络的TCP性能。     

Framework based on stochastic L-Systems for modeling IP traffic with multifractal behavior

This paper presents and compares a set of traffic models, and associated parameter fitting procedures, based on so-called stochastic L-Systems, which were introduced by biologist A. Lindenmayer as a method to model plant growth. Starting from an initial symbol, an L-System generates iteratively sequences of symbols, belonging to an alphabet, through successive application of production rules. In a traffic modeling context, the symbols are interpreted as packet arrival rates or mean packet sizes, and each iteration is associated to a finest time scale of the traffic. These models are able to capture the multiscaling and multifractal behavior sometimes observed in Internet traffic. We describe and compare four traffic models, one characterizing the packet arrival process, and the other three characterizing both the packet arrival and the packet size processes. The models are tested with several measured traffic traces: the well-known pOct Bellcore, a trace of aggregate WAN traffic and two traces of specific applications (Kazaa and Operation Flashing Point). We assess the multifractality of these traces using Linear Multiscale Diagrams. The traffic models are evaluated by comparing, for the measured traffic and for traffic generated according to the inferred models, the probability mass function, the autocovariance function and the queuing behavior. Our results show that the L-System based traffic models that characterize both the packet arrival and packet size processes can achieve very good fitting performance in terms of first- and second-order statistics and queuing behavior.     

适用于大规模无线传感器网的流量优化系统设计

针对大规模无线传感器网络(WSN)流量随访问者数量增加而上升的问题,设计并实现了一种适用于构建大型WSN并降低系统流量的应用系统框架。系统采用IPv6和低功耗无线个域网的IPv6技术(6LoWPAN)搭建大规模WSN,使用消息队列遥测传输(MQTT)协议和针对WSN设计的消息队列遥测传输(MQTT-SN)协议在应用层搭建了连接WSN和传统互联网的发布/订阅结构。实验结果显示,当系统中存在5个传感器节点时,与受限应用协议(CoAP)构建的WSN应用系统相比,提出的系统框架的数据流量仅为前者的18%左右。这表明该系统框架可有效地控制访问者增加对WSN流量造成的影响。     

无线传感器网络QoS仿真与研究

无线传感器网络在军事和民用领域均具有广阔的应用前景,但由于传感器节点资源的限制,网络能否满足在实际应用中的QoS要求是一个重要问题。本文对无线传感器网络的主要QoS指标进行了介绍,并分别从能量效率、丢包率、吞吐量和传输时延等主要QoS指标对三种典型拓扑结构的无线传感器网络进行了分析;实现了基于NS2的无线传感器网络通用仿真平台,借助此平台对典型拓扑结构的传感器网络主要QoS指标进行了仿真验证和分析,得到了不同拓扑结构对无线传感器网络QoS指标的影响程度。