基于遗传算法的无线网状网QoS多播路由算法

探讨了基于遗传算法的无线网状网QoS多播路由算法,选用边集表示方式对多播树进行编码,其空间复杂度为O(N),给出了该编码方式下的初始种群生成算法RandWalkMT,同时对传统的遗传操作进行改进使子代个体中不会产生非法多播树,从而避免了复杂的惩罚机制或多播树修复算法。实验表明该算法收敛快且性能较好。     

无线Mesh网络路由协议的研究进展

在简要介绍无线Mesh网络特性的基础之上,对路由协议中若干关键技术的研究状况进行了总结和综述,重点讨论面向无线Mesh网络的路由度量的设计思路、多信道多无线接口环境下节点的自适应信道分配策略以及结合无线介质的广播特性的寻路算法的分析.详细讨论了上述因素对于路由协议性能的具体影响,深入分析了当前研究的优缺点.同时,鉴于无线链路上传输的不可靠和高误码率,详细介绍了跨层协议设计的相关内容.     

多信道无线网状网自适应路由算法

针对无线网状网的网络容量优化问题,通过建立无线网状网容量优化的数学模型,利用线性规划公式对无线网状网的路由问题进行描述,在此基础上提出了一个自适应路由算法。根据网络的拓扑结构和业务请求特点,自适应地改变路由扩张因子和负载均衡率进行优化路由,达到提高无线网状网的网络容量的目的。仿真结果表明,该算法能明显提高网络容量。     

Coordinated opportunistic routing protocol for wireless mesh networks

Opportunistic routing is an emerging research area in Wireless Mesh Networks (WMNs), that exploits the broadcast nature of wireless networks to find the optimal routing solution that maximizes throughput and minimizes packet loss. Opportunistic routing protocols mainly suffer from computational overheads, as most of the protocols try to find the best next forwarding node. In this paper we address the key issue of computational overhead by designing new routing technique without using pre-selected list of potential forwarders. We propose a novel opportunistic routing technique named, Coordinated Opportunistic Routing Protocol for WMNs (CORP-M). We compare CORP-M with well-known protocols, such as AODV, OLSR, and ROMER based on throughput, delivery ratio, and average end-to-end delay. Simulation results show that CORP-M, gives average throughput increase upto 32%, and increase in delivery ratio (from 10% to 20%). We also analyze the performance of CORP-M and ROMER based on various parameters, such as duplicate transmissions and network collisions, by analysis depicts that CORP-M reduces duplicate transmissions upto 70% and network collisions upto 30%.     

A fuzzy queue-aware routing approach for wireless mesh networks

Recent advances in Wireless Mesh Networks (WMNs) have overcome the drawbacks of traditional wired and ad-hoc networks and now they are seen as a means of allowing last mile communications with quality level assurance in Future Multimedia Systems. However, new routing schemes are needed to provide end-to-end Quality of Service (QoS) and Quality of Experience (QoE) support for delay/loss/jitter-sensitive multimedia applications. The well-known OLSR (Optimized Link State Routing) protocol with ETX (Expected Transmission Count) metric brings many benefits to the path selection process, but has a drawback with regard to queue availability management, which reduces the system performance. This problem is caused when OLSR-EXT control messages are exchanged and the queues of mesh routers along the end-to-end communication path are overloaded. As a result, multimedia-related packets will suffer from loss/delay/jitter and the overall system performance will decrease. This paper proposes the Optimized Link State Routing-Fuzzy ETX Queue (OLSR-FEQ) protocol to overcome the limitations of OLSR-ETX regarding queue availability, QoS and QoE assurance. OLSR-FEQ optimizes network and user-based parameters by coordinating queue availability, QoS and fuzzy issues in the routing decision process as a way of allocating the best paths for multimedia applications. Performance evaluations were carried out with the Network Simulator (NS-2.34) to show the benefits of the proposed solution when compared with existing routing schemes, namely OLSR-ETX, OLSR-FLC, OLSR-MD and HWMP (IEEE 802.11s standard), regarding QoS (unsuccessful packet delivery and throughput) and QoE (PSNR, SSIM, VQM and MOS) parameters.     

无线网状网络的多路径路由与调度算法

提出了一种保障服务质量的多路径路由算法,数据分组可通过多条不同的路径进行传输,以提升网络总吞吐量性能.进一步提出了一种多路径调度策略.通过使用调度策略,基于当前可用带宽信息和路径所引入的时延信息,数据分组在传输前可被分成多段并通过不同的路径发送,根据路径时延调整优化调度策略,从而使得数据可通过在不同的路径上进行更高效地传输.仿真实验进一步验证了本文提出的路由机制和调度策略在不同网络负载下的优越性.     

A quality based routing protocol for wireless mesh networks

Wireless mesh networks can provide low-cost solutions for extending the reach of wireless access points by using multi-hop routing over a set of stationary wireless routers. The routing protocol for these networks may need to address quality considerations to meet the requirements of the user. In this paper, we present a quality based routing protocol for wireless mesh networks that tries to maximize the probability of successful transmissions while minimizing the end-to-end delay. The proposed routing protocol uses reactive route discoveries to collect key parameters from candidate routes to estimate the probability of success and delay of data packets transmitted over them. To achieve accurate route quality assessments, a new route quality metric is proposed that uses performance models of data packet transmissions as opposed to estimating route quality from the transmission of control packets, which have different transmission characteristics. These models are developed after careful evaluations of multi-hop wireless transmissions and validated by computer simulations. Relevant parameters that can be used to assess the route quality metric using these models are explained. Extensive performance evaluations of the proposed quality based routing protocol are presented and its benefits in comparison to some other known routing protocols are discussed.     

基于无线Mesh网络的集中式自愈路由算法研究

针对现有无线Mesh网络路由算法寻路洪泛严重、自愈性能较差等问题,引入集中式路由的思想,结合多路径策略,提出了一种集中式自愈路由算法(Centralized Self-healing Routing Protocol,CSRP),即通过各节点主动上传链路状态消息至Root节点的方式得到全网最新加权拓扑,并为源目节点之间计算全局最优路由。采用节点不相交多路径备份策略,实现失效路由的快速自愈。加入基于链路质量感知的Root节点切换机制,保证路由申请及分发的可靠性。仿真结果表明,CSRP算法有效抑制了洪泛现象、提升了网络性能,相比于现有经典相关算法路由开销至少降低67%,时延平均降低45%,包递交率平均提升8%。     

无线网络负载均衡的干扰感知路由度量

无线信道干扰和负载分布不均匀严重影响无线网络的网络吞吐量、端到端延时等。在已有的路由度量的基础上,充分继承其通过邻居节点负载描述干扰强度的优势,进一步分析节点负载的影响,提出负载均衡的干扰感知路由度量,将干扰邻居节点的数量、负载和距离综合作用结果作为流间干扰强度,使用节点处的平均队列长度捕捉节点负载,并改进期望传输时间消除链路的不对称性,实现负载均衡和干扰感知,避开热点区域。同时将LBIA合并入路由协议。仿真结果表明:该路由度量可以有效地实现网络负载均衡,提升网络整体性能。     

XCHARM: A routing protocol for multi-channel wireless mesh networks

Recent experimental results have pointed out the impact of physical layer multi-path fading and co-channel interference as the key factors influencing packet delivery among mesh routers (MRs) in wireless mesh networks. In addition, in a multi-channel environment, there exists significant power spectral overlap among channels used by MRs, leading to adjacent channel interference. In this paper, a cross-layer multi-radio, multi-channel routing protocol, XCHARM, is proposed in which the key contribution is the selection of the next hop, channel and transmission rate based on fading and interference concerns. The key features of our proposed protocol are as follows: (i) Routes are chosen based on the availability of channels that support high data rates, exhibit acceptable interference levels and long term resilience to fading related losses, (ii) The path latency is analytically calculated in advance for the candidate routes, accounting for channel induced errors, link layer contention, forward error correcting (FEC) codes, and the allowed data rates over the chosen channels, (iii) The route maintenance is performed by first attempting to identify and correct the point of failure before undertaking a global recovery action. An extensive performance evaluation, spanning the network, link and physical layers, reveals the benefits of adopting our cross-layer routing solution for wireless mesh networks.     

基于链路状态认知的无线Mesh网路由协议

在分析无线Mesh网路由协议所面临挑战的基础上,结合无线Mesh网络的性能要求,以优化链路状态路由(OLSR)协议为原型,采用跨层设计理论,提出了一种基于链路状态良好程度的路由协议LR-OLSR。该协议引入了认知无线网络中的环境感知推理思想,通过对节点负载、链路投递率和链路可用性等信息进行感知,并以此为依据对链路质量进行推理,获得网络中源节点和目的节点对之间各路径状态良好程度的评价,将其作为路由选择的依据,实现对路由的优化选择,提高网络的吞吐量,达到负载均衡。通过与OLSR及其典型改进协议P-OLSR、SC-OLSR的对比仿真结果表明,LR-OLSR能够提高网络中分组的递交率,降低平均端到端时延,在一定程度上达到负载均衡。     

一种基于mesh网络的多径路由协议

针对无线mesh网络的特点提出了一种基于源节点建立、目的节点维护的多径路由协议。该协议采用目的节点更新mesh结构的机制,能实时维护最优路径和其余多条路径,当节点移动或其他原因造成链路断开时,不需要路由修复或重建,从而降低了丢包率和端到端时延,且通过基于源节点建立路由的方式有效地减少了控制开销。仿真结果表明,该算法具有良好的性能。     

基于遗传算法的无线网状网QoS路由算法*

对基于遗传算法的多QoS约束路由算法进行了研究,实验结果表明,该算法在无线网状网中是一种高效的路由算法.     

A survey on routing algorithms for wireless Ad-Hoc and mesh networks

Wireless networking technology is evolving as an inexpensive alternative for building federated and community networks (relative to the traditional wired networking approach). Besides its cost-effectiveness, a wireless network brings operational efficiencies, namely mobility and untethered convenience to the end user. A wireless network can operate in both the “Ad-Hoc” mode, where users are self-managed, and the “Infrastructure” mode, where an authority manages the network with some Infrastructure such as fixed wireless routers, base stations, access points, etc. An Ad-Hoc network generally supports multi-hopping, where a data packet may travel over multiple hops to reach its destination. Among the Infrastructure-based networks, a Wireless Mesh Network (with a set of wireless routers located at strategic points to provide overall network connectivity) also provides the flexibility of multi-hopping. Therefore, how to route packets efficiently in wireless networks is a very important problem.A variety of wireless routing solutions have been proposed in the literature. This paper presents a survey of the routing algorithms proposed for wireless networks. Unlike routing in a wired network, wireless routing introduces new paradigms and challenges such as interference from other transmissions, varying channel characteristics, etc. In a wireless network, routing algorithms are classified into various categories such as Geographical, Geo-casting, Hierarchical, Multi-path, Power-aware, and Hybrid routing algorithms. Due to the large number of surveys that study different routing-algorithm categories, we select a limited but representative number of these surveys to be reviewed in our work. This survey offers a comprehensive review of these categories of routing algorithms.In the early stages of development of wireless networks, basic routing algorithms, such as Dynamic Source Routing (DSR) and Ad-Hoc On-demand Distance Vector (AODV) routing, were designed to control traffic on the network. However, it was found that applying these basic routing algorithms directly on wireless networks could lead to some issues such as large area of flooding, Greedy Forwarding empty set of neighbors, flat addressing, widely-distributed information, large power consumption, interference, and load-balancing problems. Therefore, a number of routing algorithms have been proposed as extensions to these basic routing algorithms to enhance their performance in wireless networks. Hence, we study the features of routing algorithms, which are compatible with the wireless environment and which can overcome these problems.     

A routing protocol suitable for backhaul access in wireless mesh networks

This work proposes the Wireless-mesh-network Proactive Routing (WPR) protocol for wireless mesh networks, which are typically employed to provide backhaul access. WPR computes routes based on link states and, unlike current routing protocols, it uses two algorithms to improve communications in wireless mesh networks taking advantage of traffic concentration on links close to the network gateways. WPR introduces a controlled-flooding algorithm to reduce routing control overhead by considering the network topology similar to a tree. The main goal is to improve overall efficiency by saving network resources and avoiding network bottlenecks. In addition, WPR avoids redundant messages by selecting a subset of one-hop neighbors, the AMPR (Adapted MultiPoint Relay), needed to reach all two-hop ones. We first analyze the proposed algorithms compared with the algorithms used by OLSR for the same tasks in terms of running time, optimality, and number of routing messages. Results show that the algorithms proposed by WPR are more efficient than the algorithms used by OLSR in running time and number of routing messages. In addition, we also perform simulations to evaluate the performance of WPR. Results reveal that the aggregated throughput of WPR outperforms OLSR by up to 27% using a combination of web and backbone internal traffic despite our design assumption of traffic convergence toward gateways.     

一个高效的双向无线Ad Hoc网络匿名路由协议

分析了Ad Hoc网络现有匿名路由协议的不足,提出了一个轻量级的,能提供良好匿名保护的基于反应式的源路由协议的匿名路由协议。该协议利用布隆过滤器实现了在ASR中定义的身份匿名、路由匿名和位置/拓朴匿名。它主要使用的是哈希运算,并在不破坏协议匿名性的前提下,通过控制路由请求包避免其在网络中传输时间过长而提高整个网络的效率。协议中建立起的匿名链路具有双向性,这也降低了匿名协议的耗费。仿真数据与分析证明了新协议的有效性与匿名性。     

一个高效的Ad Hoc网络匿名路由协议

提出了一个新型高效的适用于小型AdHoc网络的匿名路由协议。该协议建立了一种源节点和目的节点间伪名同步机制,并引入移动代理来防止恶意节点对网络的攻击。利用哈希链性质实现了节点身份的匿名和跳数控制。与一般的需要公钥加密的匿名协议相比,具有较低的网络延迟和更高的运算效率。     

Integrated topology control and routing in wireless optical mesh networks

We study the problem of integrated topology control and routing in Free Space Optical (FSO) mesh backbone networks. FSO links are high-bandwidth, low interference links that can be set-up very fast, making them suitable for mesh networking. FSO networks are highly constrained by interface constraints, i.e., constraints on the number of FSO links a node can establish. We prove the problem to be NP-Hard and propose efficient algorithms for integrated topology control and single-path or multi-path routing.     

Multicast routing protocols in wireless mesh networks: a survey

Wireless mesh networks (WMNs) introduce a new type of network that has been applied over the last few years. One of the most important developing issues in WMNs is multicast routing, which is a key technology that provides dissemination of data to a group of members in an efficient way. In this article, after an introduction about the structure of a WMN, multicast routing algorithms and protocols in WMNs are surveyed in a detailed and efficient manner. Moreover, effort is made to scale the study into one of the important potential capabilities of multicast routing mechanisms in WMNs, which is taking advantage of using different channels and radios association. While nodes in a single-radio mesh network operating on single-channel have restrictions for capacity, equipping mesh routers with multiple radios using multiple channels can decrease the intention of capacity problem as well as increase the aggregate bandwidth available to the network and improving the throughput. Hence, the purpose of channel assignment is to decrease the interferences while increasing the network capacity and keeping the connectivity of the network. Therefore, this article investigates the multicast protocols considering a definition of three types of WMNs, based on channel-radio association including SRSC, SRMC and MRMC. In its follow, a classification for multicast routing algorithms regarding the achieved optimal solutions will be presented. Finally, a study of MRMC and its relevant problems will be offered, considering the joint channel assignment and the multicast tree construction problem.