一种低时延的短波自组网优化链路状态路由协议

优化链路状态路由(Optimized Link State Routing,OLSR)协议是一种先验式路由协议,网络中的所有节点通过周期性地发送控制消息来计算全网路由信息。在短波自组织网络中,节点周期性地发送控制消息会占据大量的信道资源,大幅增加网络的控制开销,浪费短波有限的带宽资源,导致网络通信性能急剧下降。其次,受到地形地貌、天线方向和接收性能的个体差异等影响,造成无线链路不稳定,导致网络中存在非对称链路,增加了通信端到端时延。为此,提出了一种低时延的短波自组网OLSR协议。该协议在执行MPR(Multipoint Relay)选择算法时综合考虑了节点的连接度和链路可靠性,在优化MPR节点个数的同时选择链路可靠性较大的节点作为MPR节点,在进行路由选择时能够利用网络中的非对称链路。仿真结果表明,该协议能优化数据包投递成功率、吞吐量、端到端时延和网络控制开销等性能指标。     

移动Ad hoc路由协议中的节点预测研究

在移动Ad hoc网络中,节点是随意移动的,为确定某一时刻的网络拓扑,必须首先探测出网络中所有节点的位置和移动特征,这样也能避免Ad hoc网络频繁出现链路故障。为此,提出一种继承自AOMDV协议的增加节点预测的新型路由协议NP-AOMDV,并与AOMDV在吞吐量、端到端时延、路由控制开销等做性能对比,通过NS2下的仿真结果分析可知,NP-AOM-DV比AOMDV性能有了一定的提高。     

能量感知和链路稳定度的多径MANET路由

在移动自组织网络中,相对于单路径路由算法而言,多路径路由算法可以均衡网络负载、提高路由的可靠性。通过对AOMDV路由协议进行改进,提出了基于能量感知和链路稳定度的多径MANET路由协议ELMRP。ELMRP协议综合考虑了节点的剩余能量和链路稳定度,根据路径的剩余能量和稳定度计算代价值,按照代价值在多条节点不相交路径上分配数据流量。仿真结果表明,和AOMDV路由协议相比,ELMRP协议延长了网络的生存时间,提高了数据分组递送率,降低了路由发现频度。     

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。     

基于链路可用性预测的AODV路由协议研究

传统的AODV路由协议无法适应Ad hoc网络拓扑的高度动态变化.对AODV路由算法进行链路可用性预测扩展,节点通过接收分组的能量值和链路连续可用时间选择最可靠的路径进行路由,并在链路真正失效之前启动预先修复过程.仿真结果表明,改进后的AODV协议提高了分组的投递率,降低了分组端到端平均传输延时,路由协议的可靠性得到改进.     

无线Mesh网络多路径路由协议的研究

L2MPM路由协议工作在第2层,属于多经路由中的备份路由,但并未考虑主路经与备份路径之间存在链路相交的问题,降低了网络的容错能力。因此,在L2MPM协议的基础上,提出了LD-L2MPM路由协议。该协议通过采用链路不相交策略,在Hello包中添加第一跳和最后一跳字段来确保所选的两条路径是链路不相交。仿真结果表明,与原有协议相比,数据包投递率提高约6%,平均端到端时延降低约5%。     

一种贪婪地理路由协议的改进算法

贪婪转发策略广泛应用于无线传感网络(WSNs)的地理路由协议中,但是,该协议存在数据包丢失严重以及在遭遇路由空洞时路由效率低下的不足。为此,提出一种贪婪地理路由协议的改进算法,记为GPSR-I算法。GPSR-I算法在选择下一跳转发节点时,利用节点离目的节点距离、方向以及节点密度信息计算度量值,然后依据该度量值决策下一跳转发节点。仿真数据表明,与GPSR相比,GPSR-I算法能够有效降低平均端到端传输时延、路由开销,并提高了数据包传输率。     

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。     

移动Ad Hoc网络中基于Qos的多路径路由协议研究

针对现有移动Ad Hoc网在大流量业务下无法提供高质量QoS保障的问题,通过推导证明提出了路径长度限制的路径稳定的约束关系,进而将QoS的判定因子引入一种确定性的最优权值约束路由算法进行实例化,并在该路由算法的基础上提出了基于QoS保障的多路径路由协议(MP-QAODV).通过仿真,验证了MP-QAODV协议在平均端到端时延、端到端数据分组投递率、归一化路由开销等方面优于AODV和AOMDV协议.     

改进的可靠信道路由算法在认知无线电Ad-hoc网络中的应用

针对认知无线电网络中传统路由可靠性较低的问题,提出了一种改进的可靠信道路由算法(Improved reliable channel routing,IRCR)。算法根据认知无线电网络频谱的动态性,利用相邻节点间信道利用率,选择可靠邻节点,并根据可靠邻节点建立可靠路由。仿真结果表明,与传统频谱感知按需路由协议(spectrumaware on-demand routing protocol,SORP)相比,IRCR具有较高的数据包投递率和较低平均时延。     

End-to-End Link Reliable Energy Efficient Multipath Routing for Mobile Ad Hoc Networks

Among the many multipath routing protocols, the AOMDV is widely used in highly dynamic ad hoc networks because of its generic feature. Since the communicating nodes in AOMDV are prone to link failures and route breaks due to the selection of multiple routes between any source and destination pair based on minimal hop count which does not ensure end-to-end reliable data transmission. To overcome such problems, we propose a novel node disjoint multipath routing protocol called End-to-End Link Reliable Energy Efficient Multipath Routing (E2E-LREEMR) protocol by extending AOMDV. The E2E-LREEMR finds multiple link reliable energy efficient paths between any source and destination pair for data transmission using two metrics such as Path-Link Quality Estimator and Path-Node Energy Estimator. We evaluate the performance of E2E-LREEMR protocol using NS 2.34 with varying network flows under random way-point mobility model and compare it with AOMDV routing protocol in terms of Quality of Service metrics. When there is a hike in network flows, the E2E-LREEMR reduces 30.43 % of average end-to-end delay, 29.44 % of routing overhead, 32.65 % of packet loss ratio, 18.79 % of normalized routing overhead and 12.87 % of energy consumption. It also increases rather 10.26 % of packet delivery ratio and 6.96 % of throughput than AOMDV routing protocol.     

基于节点能量策略的AOMDV路由算法改进

通过对AOMDV多径协议进行改进,提出了一种基于节点剩余能量策略MMBCR的多径协议(EAOMDV)。改进协议以节点剩余能量为备份路径的度量对AOMDV多径协议进行改进。使用NS2软件进行仿真,通过改变节点的暂停时间来比较EAOMDV协议和AOMDV协议的性能。仿真结果表明,与AOMDV多径协议相比,新协议路由开销和丢包率有所增加,但降低了网络的总能耗并减少了某时刻耗尽能量的节点数目,从而延长了网络的存活时间。     

A Shoelace-Based QoS Routing Protocol for Mobile Ad Hoc Networks Using Directional Antenna

In this paper, we propose a new quality-of-service (QoS) routing protocol for mobile ad hoc network (MANET) using directional antennas. The proposed scheme offers a bandwidth-based routing protocol for QoS support in MANET using the concept of multi-path. Our MAC sub-layer adopts the CDMA-over-TDMA channel model. The on-demand QoS routing protocol calculates the end-to-end bandwidth and allocates bandwidth from the source node to the destination node. The paths are combined with multiple cross links, called shoelace, when the network bandwidth is strictly limited. Due to the property of the directional antenna, these cross links can transmit data simultaneously without any data interference. We develop a shoelace-based on-demand QoS routing protocol by identifying shoelaces in a MANET so as to construct a QoS route, which satisfied the bandwidth requirement, more easily. The shoelace-based route from the source to the destination is a route whose sub-path is constructed by shoelace structure. With the identified shoelaces, our shoelace-based scheme offers a higher success rate to construct a QoS route. Finally, simulation results demonstrate that the proposed routing protocol outperform existing QoS routing protocols in terms of success rate, throughput, and average latency.     

Survey of Secure Routing Protocols for Wireless Ad Hoc Networks

The mobile ad hoc network is a type of wireless network characterized by mobile nodes without a centralized administration. Frequent variations of the topology and the nature of the radio links have a negative impact on the stability of the links. Indeed, the link quality deteriorates rapidly and link breaks become frequent. To overcome these problems, new forms of routing protocols are used as the MultiPath routing. In addition, routing protocols require the knowledge of the nodes neighborhood to build and manage routes. The neighbor discovery process is performed by a Hello protocol. The Hello protocol typically involves several parameters such as the packet’s period; node’s transmit power, node’s position and node’s battery level. The purpose of this paper is to change the behavior of ad hoc On demand Multi-path Distance Vector (AOMDV) routing protocol by considering the density of the nodes as well as the interference of the neighboring nodes. This selection of paths goes through two stages. In the first step, we study the impact of the neighbor discovery process to select a set of paths having a minimum number of neighboring nodes to diminish contention problems and interference rate. In the second step, the Interference Ratio (IR) metric is used to select the paths in which the nodes are surrounded by a minimum of interference. We choose for our study two proposed approaches based on AOMDV routing protocol. The first is called AOMDV_neighbor and considers the density parameter as a path metric. The second is called AOMDV_neighbor_IR which considers the interference rate (IR) between each node and its neighborhood as a path metric. We evaluate the proposed routing protocols performance under various NS2 simulation scenarios in a shadowing environment.

     

An adaptive‐aware energy and queue improvement of AOMDV

Because the node energy and network resources in the wireless sensor network (WSN) are very finite, it is necessary to distribute data traffic reasonably and achieve network load balancing. Ad hoc on‐demand multipath distance vector (AOMDV) is a widely used routing protocol in WSN, but it has some deficiencies: establishes the route by only using hop counts as the routing criterion without considering other factors such as energy consumption and network load; forwards route request in fixed delay resulting in building the nonoptimal path; and cannot update the path status after built paths. For the deficiency of AOMDV, this paper proposes a multipath routing protocol adaptive energy and queue AOMDV (AEQAOMDV) based on adaptively sensing node residual energy and buffer queue length. When sending a routing request, the forwarding delay of the routing request is adaptively adjusted by both the residual energy and the queue length of the intermediate node; when establishing routes, a fitness is defined as a routing criterion according to the link energy and the queue load, predicting the available duration of the node based on the energy consumption rate and adjusting the weight of the routing criterion by the available duration of the node; after the routes are established, the path information status are updated via periodically broadcasting Hello that carries the path information with the minimum fitness, making the source node update the path information periodically. By using NS‐2, simulations demonstrate that compared with AOMDV, AEQAOMDV has obvious improvements in increasing packet delivery ratio, reducing network routing overhead, reducing route discovery frequency, and decreasing the network delay. And AEQAOMDV is more suitable for WSN.     

基于AOMDV的多径路由协议改进及仿真分析

Ad Hoc网络是由一些移动节点组成、拓扑结构复杂且动态变化的自组织网络。网络中没有固定的网络基础设施,对路由协议要求较高。通过在每个节点的路由表和发送接收包中增加能量参数等措施,提出基于AOMDV的多路径路由协议改进方案PE-AOMDV协议,最后在NS2仿真平台上实现对改进的AOMDV多路径路由协议仿真分析。仿真结果表明：与AOMDV协议相比,新的基于能量的多路径路由协议PE-AOMDV的传输时延和路由开销都有所降低,并提高了分组投递率,从而提高了网络性能。     

Design and Performance Analysis of a Proxy-Based Indirect Routing Scheme in Ad Hoc Wireless Networks

The majority of existing ad hoc network routing protocols has a tendency to use the shortest single path from a source to a destination. However, in constantly changing topologies such as those in mobile ad hoc wireless networks, the shortest single path is not only unreliable for reachability but also unsuitable for traffic load equilibrium. In order to improve routing performance and make optimum use of the limited resources, the congestion must first be relieved as much as possible and the routing path be made available at all times. In this paper, we propose a novel scheme, called the Applicative Indirect Routing (AIR), to control network traffic congestion and refine route availability by coping with unreliable links quickly. The proposed scheme, acting as a proactive routing protocol, utilizes additional information about the neighbors shared by the sender and the receiver to find an alternative for the original path with unreliable links. The additional bandwidth usage in AIR to obtain the information about shared neighbors (defined as proxy candidates) is so minimal that the bandwidth availability for user data traffic is not significantly affected. Extensive simulation experiments show that compared with a conventional proactive protocol, namely Destination-Sequenced Distance Vector (DSDV), the AIR scheme leads to a much improved system performance in terms of packet delivery ratio, average end-to-end packet delay, and network reliability. We further show that, in terms of packet delivery ratio, AIR is also a competitive protocol compared with such reactive protocols as Ad hoc On Demand Distance Vector (AODV) and Dynamic Source Routing (DSR).     

Distributed channel assignment combined with routing over multi-radio multi-channel wireless mesh networks

In order to realize the reduction of equipment cost and the demand of higher capacity,wireless mesh network(WMN) router devices usually have several interfaces and work on multi-channels.Jointing channel allocation,interface assignment and routing can efficiently improve the network capacity.This paper presents an efficient channel assignment scheme combined with the multi-radio link quality source routing(MR-LQSR) protocol,which is called channel assignment with MR-LQSR(CA-LQSR).In this scheme,a physical interference model is established:calculated transmission time(CTT) is proposed as the metric of channel assignment,which can reflect the real network environment and channel interference best,and enhanced weighted cumulative expected transmission time(EWCETT) is proposed as the routing metric,which preserves load balancing and bandwidth of links.Meantime,the expression of EWCETT contains the value of CTT,thus the total cost time of channel assignment and routing can be reduced.Simulation results show that our method has advantage of higher throughput,lower end-to-end time delay,and less network cost over some other existing methods.     

MANET实时传输的可靠性研究

以IDA算法的可逆"扩散-恢复"运算为基础,本中提出一个多径路由分布式网络环境的MANET信息扩散方案.该方案因MANET实时传输网络环境中无线信道质量和路由拓扑的持续变化,动态地调整IDA算法的两个主要参数,以实现自适应的冗余机制,在节约网络资源的同时保证实时传输的可靠性.该方案的实现只需在网络层和应用层做少量的修改,使得它在实际应用中更为方便、有效.