基于多路径路由的自组网节点合作方法

为减小移动自组网中自私节点对网络性能的影响,提出了一种基于TORA协议的自组网节点合作方法TORA_CE。由于每个节点拥有多条通往目的节点的路径,在发现自私节点后,该方法能够快速切换路由,从而减小了数据传输过程中丢包的概率。TORA_CE具有更好的分布式特点,将自私节点引发的路由变化限制在自私节点附近较小的范围内,而且引入了共同邻居监听技术,并采用一跳信息计算节点的信誉值,提高了对自私节点的检测速度。使用NS2对TORA_CE进行了仿真,实验结果显示,与基于DSR协议的节点合作方法相比,TORA_CE能够明显提高网络的吞吐率。     

基于广播树的移动自组织网络合作路由协议

为了激励自组网中的自私节点使其参与网络合作,提出了一种基于VCG机制计算转发节点支付的BEC协议,此协议对LDTTO协议的支付方案进行了改进,使源节点失去作弊动机.在路由发现阶段,创建以目的节点为根的广播树,将节点拓扑信息沿广播树以单播方式发送到根节点,降低了网络控制负载开销和路由发现延迟.BEC协议引入了容错机制,通过在混杂模式下对父节点的监听来确保数据的正确传输.在BEC协议中,高度为O(lgn)的广播树,路由发现过程的消息负载为O(nlogn),低于LOTID协议的O(n2).仿真实验结果表明,与现有的几种重要协议相比,BEC协议具有更低的消息负载和网络延迟.     

移动自组网的GloMoSim仿真研究

移动自组织网络(MANET)由于其灵活的架构和组网特点,已经成为下一代无线网络应用中的关键技术,路由协议是其研究的一个重点,针对这些协议的有效仿真和验证是必要的。全球移动信息系统仿真库在移动自组网的仿真研究中得到了很广泛的应用,尤其是对大规模网络的仿真支持。本文重点介绍了GloMoSim仿真环境的特点和机理,并结合典型的自组网路由策略,分析比较了这些路由协议的性能,最后给出相关的结论。     

移动自组网选播路由协议ARAD

针对移动自组(ad hoc)网的特点,提出了一种适合ad hoc移动网络的选播路由协议——ARAD协议.该协议在充分考虑选播路由特点的基础上,将ad hoc按需距离矢量路由(AODV)协议的路由发现机制与动态源路由(DSR)协议的缓存源路由技术相结合,在动态变化的ad hoc网络中实现了一种高效的选播路由.模拟结果表明,在动态的网络环境下,ARAD协议能够取得良好的性能.     

一种基于AODV协议的无线传感器网络多路径路由改进方案

本文分析了AODV协议在静态无线传感器网络中的传输过程,针对单路径路由机制存在的中间节点路由延迟较大、负载集中而导致的网络节点能耗不均、数据传输效率低的问题,提出了一种针对AODV协议的改进方案。此改进方案在AODV协议中引入了多路径路由机制,同时在路径选择时考虑了节点剩余能量,从而在无线传感器网络数据传输中能避免热点,较好的解决断链问题,同时减少了原AODV路由查找的次数和延时,降低了路由开销。     

高可靠性煤矿井下火源无线预警监测系统

鉴于无线ZigBee协议传输数据率低、距离短,为进行煤矿井下大范围高密度火源监测任务,设计一种高可靠性煤矿井下火源无线预警监测系统。在井下煤自燃隐蔽区域布置感温电缆,利用WaveMesh移动自组网协议多跳网络并行传递数据,根据节点路径选择算法选择传输的最佳路径,通过光纤冗余环网传输至监测终端。该系统以可靠性、健壮性和易移植性为设计原则,针对硬件抗干扰和防爆,射频转发相邻节点数据并设置避让机制,WIFI模块或RS485模块及接口模块二选一通信,光纤冗余环网传输数据。经试验表明,无线传感网络最大通信距离为37 m。采用WaveMesh多径路由协议,组成多跳网络在不同路由间自由切换,能够充分利用无线信号的冗余性。     

移动自组网的安全性问题研究

移动自组网是一种特殊的无线移动网络,由于采用动态拓扑、无线信道、有限电源、分布式控制等技术和方式,所以更易受攻击和安全威胁.本文首先对移动自组网作了简要概述,然后针对安全问题进行了深入分析,并较详细地介绍了已有的各种路由安全解决方案,最后指出了移动自组网安全中今后需要研究的若干关键问题.     

基于位置信息的水声传感器网络路由协议

由于水下环境与地面环境不同,无线传感器网络中的协议不能直接应用于水下传感器网络中。针对水下环境的特点,提出了一种适用于水下传感器网络的路由协议。它是一种可扩展的、能量高效的路由协议。仿真结果显示:网络节点的移动速率不是很大时,该协议具有能量利用率高、数据传输成功率高和传输延时低等优点。     

GBER:一种基于簇间网关节点的节能路由协议

针对无线传感器网络现有分簇路由协议簇首节点向SINK节点传输数据时单跳传输距离较长、能量消耗严重的问题,提出了一种高效节能的基于簇间网关节点的路由(GBER)协议.GBER协议能够使簇首节点均匀地分布在网络中,并选择合适的节点成为转发簇间通信数据的网关节点,利用这些网关节点可以分担簇首节点的能量消耗,延长网络生存周期....     

自组网中一种基于跨层负载感知的蚁群优化路由协议

将蚁群优化和跨层优化方法结合起来,提出了一种基于跨层负载感知和蚁群优化的路由协议(CLAOR)。协议将整个路径中各节点MAC层的总平均估计时延和节点队列缓存的占用情况结合起来,共同作为路由选择和路由调整的重要度量标准进行按需路由发现和维护,通过拥塞节点丢弃蚂蚁分组以及借助部分兼具蚂蚁功能的数据分组实现正常路由表的维护等方法,减少了控制开销,增加了算法的可扩展性,较好地解决了自组网中现有基于蚁群优化的路由协议中普遍存在的拥塞问题、捷径问题和引入的路由开销问题。仿真结果表明,CLAOR在分组成功递交率、路由开销以及端到端平均时延等方面具有优良性能,能很好地实现网络中的业务流负载均衡。     

Mobile agent based approach for QoS routing

A mobile agent based on-demand quality of service (QoS) unicast routing scheme for supporting multimedia applications is proposed that considers bandwidth, delay and packet loss as QoS metrics for feasible path computation. A mobile agent is employed to find multiple QoS paths and select a best path among them to preserve resources so as to increase call success ratio and network bandwidth utilisation as well as adapt to network dynamics. The scheme is simulated in various network scenarios (sparse and dense networks) to verify performance and operation effectiveness, and compared with RSVP-based QoS routing by using an internet routing protocol. The results demonstrate significant improvements in call success ratio and network bandwidth utilisation compared with RSVP-based QoS routing, both in case of sparse and dense networks. Benefits of the agent-based scheme are adaptability, flexibility, and support for component-based software engineering features such as software reuse, customisation and maintainability     

一种支持多跳无线网QoS业务的MAC层接入协议

提供一定的服务质量保证(QoS)是多跳无线网络研究中的热点和难点,本文基于TDMA/FDMA机制提出了一种支持多信道多跳无线网络话音级QoS业务的MAC层接入协议RA/SRN。该协议以RBRP协议思想为基础,针对无线信道中隐藏、暴露终端造成的信道利用率降低和分组冲突问题进行改进设计,减小了信道冲突概率,提高了信道利用率,降低了信道接入时延,为网络层QoS路由协议提供了良好的支持。     

Q-Learning Based Routing Protocol for Congestion Avoidance

The end-to-end delay in a wired network is strongly dependent on congestion on intermediate nodes. Among lots of feasible approaches to avoid congestion efficiently, congestion-aware routing protocols tend to search for an uncongested path toward the destination through rule-based approaches in reactive/incident-driven and distributed methods. However, these previous approaches have a problem accommodating the changing network environments in autonomous and self-adaptive operations dynamically. To overcome this drawback, we present a new congestion-aware routing protocol based on a Q-learning algorithm in software-defined networks where logically centralized network operation enables intelligent control and management of network resources. In a proposed routing protocol, either one of uncongested neighboring nodes are randomly selected as next hop to distribute traffic load to multiple paths or Q-learning algorithm is applied to decide the next hop by modeling the state, Q-value, and reward function to set the desired path toward the destination. A new reward function that consists of a buffer occupancy, link reliability and hop count is considered. Moreover, look ahead algorithm is employed to update the Q-value with values within two hops simultaneously. This approach leads to a decision of the optimal next hop by taking congestion status in two hops into account, accordingly. Finally, the simulation results presented approximately 20% higher packet delivery ratio and 15% shorter end-to-end delay, compared to those with the existing scheme by avoiding congestion adaptively.     

An Energy Based Dynamic AODV Routing Protocol in Wireless Ad Hoc Networks

In recent years, with the rapid development of the Internet and wireless communication technology, wireless Ad hoc networks have received more attention. Due to the limited transmission range and energy of nodes in Ad hoc networks, it is important to establish a reliable and energy-balanced transmission path in Ad hoc networks. This paper proposes an energy-based dynamic routing protocol based on the existing AODV routing protocol, which has the following two aspects of improvement: (1) In the route discovery process, a node selects a suitable route from the minimum energy consumption route and the energy-balanced route designed in this paper according to a “Mark” bit that representing remaining energy of a node. (2) Based on (1), a route interruption update strategy was proposed to restart the route discovery process when node energy was used excessively. Simulation results demonstrate that compared with AODV and other existing routing protocols, proposed algorithm can reduce network energy consumption and balance node energy, thus extending the network lifetime.     

On physical layer-oriented routing with power control in ad hoc wireless networks

Routing in ad hoc wireless networks does not simply consist in finding a route with shortest length (as in wired networks with virtually error-free communication links), but it requires the creation of a stable and good quality communication route to avoid any unnecessary packet loss. In this paper,we discuss physical layer-oriented routing in ad hoc wireless networks, and we analyse the potential advantages of combining the use of power control (PC) with the chosen routing strategy. More precisely, we propose a modified ad hoc on-demand distance vector (MAODV) routing protocol, with and without PC, derived from the AODV-routing protocol by considering the bit error rate at the end of a multi-hop path as the metric to be minimised for route selection. In other words, we consider routing with a physical layer-oriented quality of service criterion, and we analyse the system performance in scenarios with either strong line-of-sight (LOS) or shadowed communications. Although in a scenario with strong LOS communications there are a few cases where the MAODV-PC protocol offers the best performance, in the presence of shadowed communications the proposed physical layer-oriented strategy is not attractive.     

Compatibility of TCP Reno and TCP Vegas in wireless ad hoc networks

Previous work has shown that TCP (transmission control protocol) Vegas outperforms the more widely deployed TCP Reno in both wired and wireless networks. It was also shown that when both TCP variants coexist on the same wired links, Reno dominates because of its more aggressive behaviour. This paper examines for the first time the compatibility between Reno and Vegas in wireless IEEE 802.11 ad hoc networks. It is shown that Vegas generally dominates in the heterogeneous Reno/Vegas network scenario; a startling result that is inconsistent with what is seen in wired networks. It is shown that the wireless ad hoc network environment does not reward the aggressive behaviour of Reno. On the other hand, Vegas, with its more accurate yet more conservative mechanisms, is able to capture most of the bandwidth. This is found to be true when using the on-demand routing protocols of dynamic source routing (DSR) or ad hoc on-demand distance vector (AODV): the failure of a node to reach a next-hop node because of media access control (MAC)-sublayer repeated collisions is reported to the routing protocol, which then declares a route error that impacts Reno in a more serious way than Vegas. When the table-driven routing protocol destination-sequenced distance vector (DSDV) is used, Reno and Vegas share the network bandwidth in a fairer manner. Generally, fairness in this environment can be improved by reducing the TCP maximum window size.     

A comparative QoS survey of mobile ad hoc network routing protocols

A mobile ad hoc network (MANET) is a wireless, dynamic, infrastructure-less, self-organized, multi-hop, and decentralized network. Each node in MANET can act as a router as well as a work station. Many routing protocols have been developed to increase the efficiency of MANET. The primary objective of this paper is a detailed QoS comparison of reactive (AODV), proactive (DSDV), and hybrid (ZRP) routing protocols of MANET in order to find which routing protocol works best in a particular network scenario. The analysis was made for TCP-based traffic patterns. The performance differentials were analyzed on the basis of normalized routing overhead, packet loss, packet delivery ratio, control packets, end-to-end delay, packet received, and packet sent with a variation of nodes density and mobility. The results were obtained using the NS-2 simulator.     

Maximum Data Generation Rate Routing Protocol Based on Data Flow Controlling Technology for Rechargeable Wireless Sensor Networks

For rechargeable wireless sensor networks, limited energy storage capacity, dynamic energy supply, low and dynamic duty cycles cause that it is unpractical to maintain a fixed routing path for packets delivery permanently from a source to destination in a distributed scenario. Therefore, before data delivery, a sensor has to update its waking schedule continuously and share them to its neighbors, which lead to high energy expenditure for reestablishing path links frequently and low efficiency of energy utilization for collecting packets. In this work, we propose the maximum data generation rate routing protocol based on data flow controlling technology. For a sensor, it does not share its waking schedule to its neighbors and cache any waking schedules of other sensors. Hence, the energy consumption for time synchronization, location information and waking schedule shared will be reduced significantly. The saving energy can be used for improving data collection rate. Simulation shows our scheme is efficient to improve packets generation rate in rechargeable wireless sensor networks.     

随机路由网络中瓶颈链路推测新算法

利用随机路由网络中链路时延分布的累积生成函数,通过端到端的时延推测网络内部链路时延分布,在此基础上,根据链路瓶颈判别定位网络内部的瓶颈链路,并用仿真模型进行了验证。仿真结果表明,在网络中存在随机路由时,本算法可以取得较好的效果。