OLSR协议MPR覆盖度对网络性能的影响分析

路由协议是无线移动自组网（Mobile Ad Hoc Networks,MANETs）的关键技术之一。针对优化链路状态路由（Optimized Link SState Routing,OLSR）协议中的多点中继（Multipoint Relay,MPR）覆盖度对网络开销的影响进行了分析。OLSR协议与一般的链路状态协议相比,其采纳了MPR机制,一定程度上抑制了网络中广播控制信息的洪泛,从而降低了网络中的控制开销,但是这种机制是否影响到路由的鲁棒性是值得探讨的问题。基于此,设计了相应的MPR选择算法并进行仿真实验。结果表明,适当提高MPR覆盖度能加快路由的收敛。     

短波Ad Hoc路由协议仿真与性能分析

为找到一种适合短波Ad hoc网络使用的路由协议,通过OPNET仿真软件对短波信道进行建模,在该模型的基础上对无线Ad Hoc常用的3种路由协议:优化链路状态路由(Optimized Link State Routing,OLSR)、反应式路由中的动态源路由(Dynamic Source Routing,DSR)和按需距离矢量(Ad hoc On Demand Distance Vector,AODV)进行仿真分析。仿真结果表明,OLSR路由协议网络时延最小、吞吐量最高和数据丢失率最低,其整体性能优于AODV及DSR路由协议,更适合于短波信道,但是OLSR路由协议也存在着开销高的不足,下一步可以针对降低路由开销进行研究。     

OLSR路由协议改进研究

优化链路状态路由协议（Optimized Link State Routing,OLSR）是Ad Hoc网络中的一种先验式的链路状态路由协议，在该协议基础上，通过在HELLO消息中加入二跳邻节点信息进行一跳广播，节点能获取所有的二跳邻节点及三跳邻节点，从二跳邻节点中选出中继节点（称之为多点二级中继节点MPL2R）覆盖三级邻节点，再从一跳邻节点中选出中继节点（称之为一级中继节点MPL1R，即原来的MPR）,MPL2R和MPL1R完成了对所有的二跳和三跳邻节点的覆盖。修改TC消息内容，并改进MPR节点选择算法。通过对OLSR路由协议的改进，增加了路由开销，但从全局看，最后计算出的路径更接近全局最优。     

基于跨层的加权自组网路由协议的设计及实现

以优化的链路状态路由（Optimized Link State Routing,OLSR）协议为原型,为无线移动自组织网络（Mobile Ad Hoc Networks,MANETs）设计了基于跨层的速率自适应的加权路由协议。该协议充分考察无线信道的时变性质,在路由计算过程中通过跨层信息共享节点的邻居关系及获取节点的当前发送速率,削减了协议的开销。将无线链路的速率与跳数相结合,设计了一种新的路由度量规则。仿真结果表明,提出的加权路由协议能够显著降低网络层的路由开销,提升网络吞吐量,降低端到端时延。     

Ad Hoc网络中实现定位的OLSR协议研究

针对Ad Hoc网络中的节点位置估计和路由控制问题,在基于OLSR(最优链路状态路由)协议的基础上提出了一种能够同时实现路由和定位的综合协议OLSR-P(最优链路状态路由和定位)。该协议对OLSR协议进行了改进,能够将路由开销和定位有效结合,并对数据包结构进行改良,利用原协议的路由开销实现定位。仿真实验结果表明:OLSR-P协议不仅能够同时实现路由和定位,还能有效地控制开销。     

基于IEEE802.11 DCF的链路预先修复AODV路由协议

基于无线自组织网络中普遍使用的底层通信协议IEEE802.11 DCF,针对广泛应用于无线自组织网络中的路由协议(AODV),提出了一种链路预先修复算法。该算法首先推算了DCF协议中的不稳定传输范围,然后通过MAC层与路由层的跨层协作,在下一跳节点移动在不稳定传输范围时就事先采取相应的路由修复措施。相对于AODV中采用节点周期性地发送HELLO消息来监测邻居节点变化的方法,该算法更为高效及时。仿真结果表明,该算法能够有效的减小端到端时延,保障了投递率。     

基于OLSR协议的无线MESH网络系统设计

本文针对传统单跳无线网络(WLAN)可伸缩性低、鲁棒性差等缺点,提出了一种基于OLSR协议的无线MESH网络系统设计方法,该方法在提高对网络拓扑变化动态适应性的同时, 达到减少控制开销的目的。每个子网选择部分节点作为网络控制分组的多点中继节点(MPR), 其它邻居节点收到该节点发送的控制分组时,只进行处理而不转发,通过这种方式显著地减少了传统先应式路由协议网络拓扑信息广播的控制分组数量。每一个 MPR 节点只报告自己与其 MPR 节点之间的链路,进一步地减少了网络控制开销。该方法在城市数字化、城市无线监控等领域具有较高应用前景。     

一种高能效低时延的LLN路由修复算法

由于低功耗有损网络(LLN)中无线链路的不稳定性和有损性,外部环境的干扰极易导致网络出现故障,从而严重影响网络性能,而LLN网络中现有路由修复算法存在控制开销冗余和修复时延较大等问题。为此,提出了一种高能效低时延的LLN路由修复算法(EELDR-RPL)。该算法通过采用“零额外控制开销通告链路故障及邻居节点信息”机制,使得链路故障节点的子节点能够及时获知链路故障以及链路故障节点的邻居情况;通过采用“自适应调整节点网络深度值”机制,使得链路故障节点能够快速地重新接入网络;通过采用“链路故障节点子节点自适应切换”机制,能够达到优化网络拓扑的目的。仿真结果表明,与现有路由修复算法相比,EELDR-RPL算法能够有效地降低路由修复时延和减少控制开销。     

自组网路由协议的仿真与性能研究

在Ad Hoc网络中,如何针对实际的应用选择一个最佳的路由协议是一个难点问题.分析DSDV,OLSR,DSR,TORA和AODV五种常用的Ad HOC路由协议,基于网络节点暂停时间及最大移动速度变化两种情况,设计了针对平均端到端时延、数据包分组传送率、路由开销和平均跳数四个指标的仿真实验.仿真结果表明:在相同的网络环境下,与其他四种协议相比,OLSR协议的平均时延、路由开销和平均跳数都较小,分组传送率也较高,性能最好.通过对五种协议性能指标的综合比较,提出了一个通用的路由选择方案.     

基于链路稳定性估计的HELLO报文自适应发送算法

标准OLSR路由协议以固定间隔周期性交互HELLO报文进行邻居感知。当网络拓扑快速变化时,固定的报文发送间隔将不能及时更新邻居信息;当网络拓扑相对稳定时,固定的报文发送间隔又会带来网络带宽的浪费。提出一种基于当前链路连接稳定性度量的HELLO报文发送间隔自适应调节算法,通过估计相邻节点间链路维持概率,选择合适的HELLO报文发送间隔。仿真结果表明,与标准OLSR路由协议以及其他相关改进算法相比,节省了网络控制报文开销,增大了吞吐量,提升了网络性能。     

HOLSR: a hierarchical proactive routing mechanism for mobile ad hoc networks

This article reviews the hierarchical optimized link state routing (HOLSR) mechanism for heterogeneous mobile ad hoc networks. In this work a heterogeneous mobile ad hoc network is defined as a network of mobile nodes that are characterized by different communications capabilities, such as multiple radio interfaces. The article focuses on proposing the HOLSR protocol. The HOLSR mechanism is derived from the OLSR protocol; however, unlike OLSR, the HOLSR protocol takes advantage of different mobile node capabilities to reduce the routing control overhead in large heterogeneous ad hoc networks, thus improving the performance of the routing mechanism.     

WRE‐OLSR,a new scheme for enhancing the lifetime within ad hoc and wireless sensor networks

Within ad hoc and wireless sensor networks, communications are accomplished in dynamic environments with a random movement of mobile devices. Thus, routing protocols over these networks are an important concern to offer efficient network scalability, manage topology information, and prolong the network lifetime. Optimized link state routing (OLSR) is one of those routing protocols implemented in ad hoc and wireless sensor networks. Because of its proactive technique, routes between two nodes are established in a very short time, but it can spend a lot of resources for selecting the multipoint relays (MPRs: nodes responsible for routing data) and exchanging topology control information. Thus, nodes playing for a long time a role of MPR within networks implementing such protocol can rapidly exhaust their batteries, which create route failures and affect the network lifetime. Our main approach relies on analyzing this concern by introducing a new criterion that implements a combination between the residual energy of a node and its reachability in order to determine the optimal number of MPRs and sustain the network lifetime. Simulations performed illustrate obviously that our approach is more significant compared with the basic heuristic used by original OLSR to compute the MPR set of a node.     

城市环境VANETS下的基于beacon控制的路由方案

车载网络(Vehicular ad hoc networks,VANETs)是一种特殊形式的网络,具有节点高速移动、拓扑频繁的变化的特性。这些特性为消息的传播带来挑战。路由机制是实现消息传递的关键因素。地理位置路由被广泛地应用于VANETS,要求节点周期广播beacon消息。然而,节点周期地广播beacon消息,降低了路由性能,特别是在城市区域,由于节点密集,每个节点均广播beacon消息,恶化了路由性能。为此,针对城市环境,提出基于beacon控制的路由协议RPBC(Routing protocol with beacon control)。在RPBC中,并非每个节点广播beacon消息,而设置有效的机制选择部分节点广播,从而降低了beacon冗余,同时,采用最短路径算法,减少数据传输跳数。仿真结果表明,提出的RBPC在分组投递率、端到端传输时延以及路由开销方面均有较好的性能。     

一种空基自组网路由协议的研究

针对传统Ad Hoc路由协议无法满足空基自组网在高动态拓扑下成功投递、路由开销和低延迟的要求,研究了一种利用空基平台已规划的航线信息来提高网络路由性能的路由协议.该路由协议由已知移动信息路由协议（MARP,mobility aware route protocol）和移动信息洪泛协议（MDP,mobility dissemination protocol）组成.MARP利用规划的航线信息预测网络拓扑并计算路由,MDP采用洪泛方式通知网络中所有节点实际拓扑和预测拓扑的差异信息.设计该协议的数据结构、链路预测机制、实际链路探测机制、多余广播减少机制.通过QualNet仿真验证,结果表明,MARP/MDP在平均报文传输延迟、报文成功投递率及路由开销方面比AODV和OLSR协议具有更优越的性能.     

Efficient on-demand routing for mobile ad hoc wireless access networks

In this paper, we consider a mobile ad hoc wireless access network in which mobile nodes can access the Internet via one or more stationary gateway nodes. Mobile nodes outside the transmission range of the gateway can continue to communicate with the gateway via their neighboring nodes over multihop paths. On-demand routing schemes are appealing because of their low routing overhead in bandwidth restricted mobile ad hoc networks, however, their routing control overhead increases exponentially with node density in a given geographic area. To control the overhead of on-demand routing without sacrificing performance, we present a novel extension of the ad hoc on-demand distance vector (AODV) routing protocol, called LB-AODV, which incorporates the concept of load-balancing (LB). Simulation results show that as traffic increases, our proposed LB-AODV routing protocol has a significantly higher packet delivery fraction, a lower end-to-end delay and a reduced routing overhead when compared with both AODV and gossip-based routing protocols.     

Moralism: mobility prediction with link stability based multicast routing protocol in MANETs

In recent research, link stability is getting tremendous attention in mobile adhoc networks (MANETs), because of several impediments that occur in a reliable and robust network. Link stability metric is used to improve network performance in terms of end-to-end delay, data success delivery ratio (DSDR) and available route time (ART). Energy consumption, bandwidth and communication delay of major concern in ad hoc networks. A high mobility of MANET nodes reduces the reliability of network communication. In a dynamic networks, high mobility of the nodes makes it very difficult to predict the dynamic routing topology and hence cause route/link failures. Multicast in MANETs is an emerging trend that effectively improves the performance while lowering the energy consumption and bandwidth usage. Multicast routing protocol transmits a packet to multicast a group at a given time instant to achieve a better utilization of resources. In this paper, node mobility is considered to map better their movement in the network. So, the links with long active duration time can be identified as a stable link for route construction. Variation in signal strength is used to identify whether the direction of the node is towards or away from estimating node. We consider signal strength as QoS metric to calculate link stability for route construction. Efforts are made to identify the link with highly probable longer lifetime as the best suitable link between two consecutive nodes. We predict the movement time of nodes that define the route path to the node destination. Exata/cyber simulator is used for network simulation. The simulation results of the proposed routing protocol are compared with on-demand multicast routing protocol and E-ODMRP, which works on minimum hop count path. Analysis of our simulation results has shown improvement of various routing performance metrics such as DSDR, ART, routing overhead and packet drop ratio.     

Proficient link state routing in mobile ad hoc network-based deep Q-learning network optimized with chaotic bat swarm optimization algorithm

Mobile ad-hoc network (MANET) is a category of ad-hoc network that can be reconfigurable its network. MANETS are self-organized networks, that can use the wireless links to connect various networks via mobile nodes: but it consumes more energy and it also has routing problems. This is the major drawback of being connected with the MANET technology. Therefore, this study proposes a new protocol as deep Q-learning network optimized with chaotic bat swarm optimization algorithm (CBS)-based optimized link state routing (OLSR) (CBS-OLSR) for MANET. This protocol reduces MANET energy usage and adopts OLSR multi-point relay (MPR) technology. MANET's OLSR and the CBS algorithm utilize a similar method to locate the best optimum path from source to destination node. By embedding the new improved deep Q-learning and OLSR algorithms, both are used for optimizing the MPR sets selection, it can efficiently diminish the energy consumption in the network topology, but automatically increase the lifespan of the network. It also enhances the package delivery ratio and decreases end-to-end delay. The experimental outcomes prove that the proposed protocol is reliable and proficient that is appropriate for numerous MANET applications.     

软件定义无人机自组网高效自适应路由维护机制

为解决软件定义无人机自组网路由维护存在的控制开销和数据包延迟偏大的问题,基于现有的OpenFlow协议提出了一种高效自适应的软件定义无人机自组网路由维护机制( Efficient and Adaptive Software-defined Unmanned Aerial Vehicle Ad Hoc Network R...