时延容忍网络中基于效用转发的自适应机会路由协议

提出了一种基于效用转发的自适应机会路由算法URD,并从理论上对该算法的有效性进行了分析.通过DTN仿真软件ONE进行了具体实现和验证,并与其他的经典协议:Epidemic,PRoPHET和SprayAndWait进行了性能对比.仿真结果表明,URD算法能够增加节点相遇的可能性,提高数据分组转发的效率,减少了网络的时延开销.     

基于社会上下文认知的机会路由算法

无线智能设备的普遍使用促进了机会网络的发展.这类网络处于间歇性连接状态,以自组织方式转发数据.路由协议设计时考虑节点携带者的社会特征和日常行为能够提高机会网络的性能.提出了一种基于社会上下文认知的机会路由算法SCOR,该算法利用网络中的社会上下文信息,通过BP神经网络模型预测节点的移动行为.路由决策过程充分考虑移动节点活动的时间和空间属性,当接收节点与发送节点同时处于网络中的同一连通域时,数据转发采用同步方式,否则采用异步方式.仿真分析和实验结果表明,与其它经典算法相比,SCOR算法提高了数据成功转发的比率,减少了网络的开销.     

基于COPE协议改进的网络编码感知机会路由算法

提出一种网络编码感知机会路由算法,将COPE协议中的机会监听和网络编码技术引入现有的机会路由机制,采用新的路由度量即LQM(链路质量度量)标准来选择备选转发节点集,在确保选择路径的编码机会的同时也在一定程度上保证了链路质量。仿真结果表明,此方法能提高网络的整体吞吐量,增加编码机会,降低平均端到端的时延。     

基于多方议价博弈的机会网络高吞吐量低开销概率路由算法

针对含自私节点的机会网络中现有基于议价博弈的概率路由算法存在的消息单向传递影响转发概率提高、依赖虚拟货币进行交易削弱节点购买力以及消息交易过程有冗余交互的问题,提出一种基于多方议价博弈的高吞吐量低开销概率路由算法——HLPR-MG。HLPR-MG算法通过将节点两两博弈扩展为多方博弈以加快消息转发概率的提升,引入“以物易物”方式增强节点购买力,并且改进现有交互机制以减少博弈次数,从而达到提高网络吞吐量的和减小控制开销的效果。理论分析验证了HLPR-MG算法设计的有效性。仿真结果表明,与基于议价博弈的现有典型路由算法GSCP和BG相比,HLPR-MG算法的吞吐量和消息传送成功率至少提高了3.63%,而控制开销和平均端到端消息时延则分别降低超17.76%和4.03%。     

认知无线电网络中基于信任的安全路由模型

针对认知无线电网络中路由受到的选择性转发攻击,提出一种基于信任的安全路由模型。通过监视节点的数据转发行为,构建节点的信任以识别恶意节点。基于路由选择必须同频谱分配紧密结合的特点,在路由发现阶段,请求信息中封装节点的可用频谱机会并避免发送给恶意节点。在路由选择阶段,利用节点信任构建可用路径信任,结合延时度量进行路由决定。同时,根据节点的信任划分对其服务请求采取不同的响应,对非可信节点的恶意行为采取更严厉的惩罚,从而激励节点在路由中的合作。仿真结果及分析表明,在选择性转发攻击下,该模型较已有模型在网络吞吐率、端到端延迟方面都有较好的表现。     

复杂网络环境下的DSR路由协议性能仿真

DSR是用于多跳无线Ad hoc网络的一个简单高效的路由协议,DSR协议由路由发现和路由维持两部分组成,允许节点在Ad hoc网络中发现、维持到任意节点的源路由.文章详细介绍了DSR协议的特点并利用Opnet Modeler 10.5构建了小规模(50节点)和大规模(100节点)复杂的(所有节点同时移动、所有节点既是源节点又是目的节点)移动自组网模型,通过改变节点移动速度及发送分组大小,对DSR路由算法的平均路由发现时间、平均路由长度、吞吐量、数据分组平均端到端的时延、及分组交付率在两种场景下进行了仿真分析和性能比较.     

Ad hoc网络两种按需路由协议性能分析

Ad hoc网络是一种无需依赖于事先布设的基础设施,而仅依靠网络内部节点之间的协作,就能够完成节点间通信的网络。比较了Ad hoc网络两种主流的按需路由协议：动态源路由协议,自组网按需距离矢量路由协议。使用基于ns-2的仿真模型进行仿真,并通过分组交付率、平均端到端时延、标准化路由负荷、对两种按需路由协议进行评估。实验结果表明即使DSR和AODV协议都是按需路由协议,但它们采取的路由机制的不同,导致它们的性能表现的巨大差异。     

采用方向性天线的ad hoc网络路由协议研究

为了降低方向性天线扫描路由发现的开销和代价,有效利用方向性天线的高空间复用度和高传输能力,提出一种采用方向性天线的ad hoc网络位置信息辅助的按需距离矢量路由协议DLAODV,协议以按需方式获取网络节点的位置信息,结合泛洪、受限泛洪、路由压缩、位置信息修正的贪婪转发策略以及分区桥接策略,充分利用方向性天线优势,有效提高路由发现效率,路由区分维护策略有效降低了路由维护开销.仿真结果显示,DLAODV能够使得网络获得高吞吐率、低时延和开销性能,相比采用全向天线的AODV协议性能获得了明显提升.     

一种基于节点能量的机会网络概率路由算法

在机会网络中,节点之间可能不存在端到端的路径.为了节省网络中节点消耗的能量,在概率路由算法的基础上提出了一种基于节点能量的概率路由算法(Energy-based Probabilistic Routing Protocol using History of Encounters and Transitivity,EBPROPHET).首先,计算两个节点相遇时节点的通信开销,然后相遇节点的剩余能量作为一个参量引入算法,选择节点剩余能量多的节点作为转发节点,最后,进行消息的转发.仿真表明,EB-PROPHET算法具有良好的路由性能,降低了整个网络的能量消耗,延长了网络的生存周期.     

无线多跳网络中一种基于网络编码的机会路由

近年来机会路由和网络编码是两种利用无线信道广播特性提高网络性能的新兴技术。相比传统的静态路由决策,机会路由利用动态和机会路由选择减轻无线有损链路带来的影响。网络编码可以提高网络的资源利用率。但编码机会依赖于多个并发流所选路径的相对结构。为了创造更多的网络编码机会和提高网络吞吐量,本文提出了一种基于流间网络编码的机会路由(ORNC)算法。在ORNC中,每个分组转发的机会路径选择是基于网络编码感知的方式进行的。当没有编码机会时,采用背压策略选择下一跳转发路径以平衡网络负载。仿真结果表明本文提出的ORNC算法能够提高无线多跳网络的吞吐量。     

网络编码在无线Mesh网络中的研究与实现

Mesh网络沿用了Ad Hoc网络中的路由协议,但Mesh网络节点移动性高,路径的生存周期短,根据无线Mesh网络自身的动态特点进行路由协议的优化成为了研究的热点。COPE编码方案是针对Mesh网络中的单播特性提出的一种新的机会网络编码机制,能够提高网络的吞吐量。通过NS2仿真平台对AODV路由协议添加COPE网络编码方案,仿真结果表明在不同网络条件下,AODV和COPE的结合增加了无线节点的编码机会,使网络的吞吐量得到了有效的提高。     

Throughput oriented forwarders selection analysis for opportunistic routing in wireless mesh network

Opportunistic routing explicitly takes advantage of the broadcast nature of wireless communications by using a set of forwarders to opportunistically perform packet forwarding. A key issue in the design of opportunistic routing protocols is the forwarder list selection problem. This paper proposes a novel routing metric which shows the end-to-end throughput and a corresponding throughput oriented opportunistic routing forwarder-selecting algorithm throughput oriented forwarders selection (TOFS) through analyzing forwarding characteristics of forwarders. The algorithm puts forward a constraint mechanism that controls the number of forwarders by constraint of throughput for forwarders selection, achieving a better balance between number of forwarders and effective link stability by introducing the factor of transmission time. Simulation results show that the algorithm can improve the network end-to-end throughput effectively over existing methods.     

Opportunistic media access control and routing for delay-tolerant mobile ad hoc networks

In delay-tolerant mobile ad hoc networks, motion of network nodes, network sparsity and sporadic density can cause a lack of guaranteed connectivity. These networks experience significant link delay and their routing protocols must take a store-and-forward approach. In this paper, an opportunistic routing protocol is proposed, along with its compatible media access control, for non-real-time services in delay-tolerant networks. The scheme is mobility-aware such that each network node needs to know its own position and velocity. The media access control employs a four-fold handshake procedure to probe the wireless channel and cooperatively prioritize candidate nodes for packet replication. It exploits the broadcast characteristic of the wireless medium to utilize long-range but unreliable links. The routing process seizes opportunities of node contacts for data delivery. It takes a multiple-copy approach that is adaptive with node movements. Numerical results in mobile ad hoc networks and vehicular ad hoc networks show superior performance of the proposed protocol compared with other routing protocols. The mobility-aware media access control and routing scheme exhibits relatively small packet delivery delay and requires a modest amount of total packet replications/transmissions.     

一种基于WSN时变性与节点剩余能量均衡的机会路由算法

 为了解决数据报文在无线传感网络中动态路由以及网络内各节点剩余能量均衡问题,该文提出了一种机会路由算法。首先,利用热力学第2定律描述数据报文在无线传感器网络中动态路由的传输过程,其中,为了表征网络内各节点状态的时变性以及剩余能量,提出了机会熵模型;其次,以机会熵模型作为选择下一跳节点的理论依据,并结合蚁群优化(ACO)算法,设计并实现了考虑网络中各节点时变性与剩余能量均衡的机会路由算法(ACO for Time Dependent Opportunistic-routing Protocol, ATDOP),使得数据报文在转发过程时,能够有效地选择下一跳节点,从而使网络内各节点的通信资源和能量资源达到负载均衡。最后,通过实验证明,相对于已有的机会路由协议,ATDOP具有报文成功传输率高、网络有效吞吐量大以及网络工作寿命长等优点。     

无线ad hoc网络中多路径负载平衡性能分析

提出了一种新颖的分析模型来计算无线ad hoc网络中多路径情况下的负载。该模型考虑到多路径的数目、路由的选取方法以及网络中节点的密度等条件，能够对不同网络条件下的负载进行较好的分析与理论计算。仿真结果与理论计算有良好的一致性，结果表明在无线ad hoc网络中简单地使用多路径路由并不能有效地平衡网络负载。这一结论与目前普遍认定的结论（在无线ad hoc网络中使用多路径路由和在有线网络中使用多路径路由一样，可以很好地平衡网络负载、增加网络的吞吐量）是不一致的。     

基于Ka/Ku相控阵天线的空基自组网协议设计

针对空基自组织网络的大容量通信需求,首先提出了基于频分复用的定向MAC协议,在邻居发现过程中将测距算法与多维尺度变换定位算法相结合得到每个节点的相对位置,并设计了双预约资源分配算法,完成定向数据传输;然后提出了定向路由协议,解决了次佳路由问题和路由应答风暴,并加入相邻搜索、链路质量评估和备用路由,降低了协议开销。空基自组网基于Ka/Ku相控阵天线的定向传播特性以及Ka/Ku频段频谱资源丰富的特点,使用频分复用、空分复用技术实现多个信道的高速并行传输,从而极大地提高网络的吞吐量。     

无线传感器网络路由协议的设计与实现

针对传统路由协议端到端时延长、丢包率过高的现实问题,提出了一种基于贪婪转发的能量感知多路径路由协议(Greedy Forward Energy-aware Multipath Routing Protocol,GFEMRP)。GFEMRP从传感器起始结点出发,如果遇到网络黑洞则选择周边转发方式,否则将选择吞吐量大、且更接近于目的结点的结点作为下一跳结点。利用了OMNET++5.0和INET框架对包括无线自组网按需平面距离向量路由协议(Ad hoc on-demand distance vector routing protocol,AODV),动态按需无线自组织网络(Dynamic MANET On-demand,DYMO),贪婪周边无状态路由无线网络(Greedy Perimeter Stateless Routing for Wireless Networks,GPSR)和GFEMRP协议在内的四种路由协议进行了仿真和比较,实验结果表明GFEMRP协议具有良好的端到端时延、丢包率等性能。     

PARO: Supporting Dynamic Power Controlled Routing in Wireless Ad Hoc Networks

This paper introduces PARO, a dynamic power controlled routing scheme that helps to minimize the transmission power needed to forward packets between wireless devices in ad hoc networks. Using PARO, one or more intermediate nodes called redirectors elects to forward packets on behalf of source–destination pairs thus reducing the aggregate transmission power consumed by wireless devices. PARO is applicable to a number of networking environments including wireless sensor networks, home networks and mobile ad hoc networks. In this paper, we present the detailed design of PARO and evaluate the protocol using simulation and experimentation. We show through simulation that PARO is capable of outperforming traditional broadcast-based routing protocols (e.g., MANET routing protocols) due to its energy conserving point-to-point on-demand design. We discuss our experiences from an implementation of the protocol in an experimental wireless testbed using off-the-shelf radio technology. We also evaluate the impact of dynamic power controlled routing on traditional network performance metrics such as end-to-end delay and throughput.     

A quantitative comparison of ad hoc routing protocols with and without channel adaptation

To efficiently support tetherless applications in ad hoc wireless mobile computing networks, a judicious ad hoc routing protocol is needed. Much research has been done on designing ad hoc routing protocols and some well-known protocols are also being implemented in practical situations. However; one major imperfection in existing protocols is that the time-varying nature of the wireless channels among the mobile-terminals is ignored; let alone exploited. This could be a severe design drawback because the varying channel quality can lead to very poor overall route quality in turn, resulting in low data throughput. Indeed, better performance could be achieved if a routing protocol dynamically changes the routes according to the channel conditions. In this paper, we first propose two channel adaptive routing protocols which work by using an adaptive channel coding and modulation scheme that allows a mobile terminal to dynamically adjust the data throughput via changing the amount of error protection incorporated. We then present a qualitative and quantitative comparison of the two classes of ad hoc routing protocols. Extensive simulation results indicate that channel adaptive ad hoc routing protocols are more efficient in that shorter delays and higher rates are achieved, at the expense of a higher overhead in route set-up and maintenance.