A reliable QoS-aware routing scheme for neighbor area network in smart grid

A reliable bi-directional communication network is one of the key factors in smart grid (SG) to meet application requirements and improve energy efficiency. As a promising communication infrastructure, wireless mesh network (WMN) can provide high speed and cost-effect communication for SG. However, challenges remain to maintain high reliability and quality of service (QoS) when applying WMNs to SG. In this paper, we first propose a hybrid wireless mesh protocol (HWMP) based neighbor area network (NAN) QoS-aware routing scheme, named HWMP-NQ, to meet the QoS requirements by applying an integrated routing metric to route decision with effective link condition probing and queue optimization. To further improve the reliability of the proposed HWMP-NQ, we present a multi-gateway backup routing scheme along with a routing reliability correction factor to mitigate the impact of routing oscillations. Finally, we evaluate the performances of the proposed schemes on NS3 simulator. Extensive simulations demonstrate that HWMP-NQ can distinguish different applications and satisfy the QoS requirements respectively, and also improve the average packet delivery ratio and throughput with a reduced routing overhead, even with a high failure rate of mesh nodes.     

基于混合无线网状网协议的改进算法研究*

HWMP提供了两种路由模式,分别是以树状路由(TBR)为基础的先应路由模式和以AODV为基础的按需路由模式.然而这个协议存在着许多问题,如可扩展性较差、效率较低、根是网络故障点,当网络业务繁重时,数据包的碰撞和丢失增加.提出一种混合无线网状网协议的改进算法来解决以上问题.在Mesh网络内部.改进后的协议能够使源节点快速...     

面向交通干线无线宽带覆盖的WMN路由协议研究

系统地比较分析了常用的WMN路由协议,包括基于三层的AODV、OLSR、B.A.T.M.A.N.、Babel以及基于二层的B.A.T.M.A.N.adv和HWMP路由协议,搭建了基于B.A.T.M.A.N.adv协议的WMN实验平台,对该协议在传输带宽、传输时延、路径切换以及重新组网方面的性能进行了深入的实验研究与分析,实验结果表明,B.A.T.M.A.N.adv协议基本可以满足交通干线无线宽带网络覆盖的性能需求,但在连接丢失后的重新组网时间约为5 s,因此其无线宽带网络覆盖需要配置足够的重叠覆盖区域以实现无缝的路径切换。     

Secure and robust multipath routings for advanced metering infrastructure

A Smart Grid is the modernization of the electricity grid using communication technology with the prime goals of reducing energy consumption as well as cost increasing reliability and creating new services for all participants. It comprises key components such as the Advanced Metering Infrastructure (AMI), which includes Neighborhood area network (NAN). When multi-hopping is considered in wireless communication, especially in WiFi and ZigBee, the range of the communication can be extended to communicate with the gateway collector in AMI network. Wireless mesh AMI network may have smart meters, a NAN gateway, and fixed as well as mobile repeaters. Though many techniques have been developed to secure on-demand routing protocols in wireless multi-hop ad-hoc networks, these protocols have shortcomings. In this paper, we propose two robust and secure multipath routing protocols for wireless mesh AMI networks. We have analyzed their robustness to various attacks. The simulation results show that the proposed protocols are better than existing secure routing protocols.     

A genetic algorithm-based system for wireless mesh networks: analysis of system data considering different routing protocols and architectures

Wireless mesh networks (WMNs) are attracting a lot of attention from wireless network researchers. Node placement problems have been investigated for a long time in the optimization field due to numerous applications in location science. In our previous work, we evaluated WMN-GA system which is based on genetic algorithms (GAs) to find an optimal location assignment for mesh routers. In this paper, we evaluate the performance of four different distributions of mesh clients for two WMN architectures considering throughput, delay and energy metrics. For simulations, we used ns-3, optimized link state routing (OLSR) and hybrid wireless mesh protocols (HWMP). We compare the performance for Normal, Uniform, Exponential and Weibull distributions of mesh clients by sending multiple constant bit rate flows in the network. The simulation results show that for HWM protocol the throughput of Uniform distribution is higher than other distributions. However, for OLSR protocol, the throughput of Exponential distribution is better than other distributions. For both protocols, the delay and remaining energy are better for Weibull distribution.     

GLBM: A new QoS aware multicast scheme for wireless mesh networks

Wireless mesh networks (WMNs) have been attracting significant attention due to their promising technology. The WMN technology is becoming a major avenue for the fourth generation of wireless mobility. Communication in large-scale wireless networks can create bottlenecks for scalable implementations of computationally intensive applications. A class of crucially important communication patterns that have already received considerable attention in this regard are group communication operations, since these inevitably place a high demand on network bandwidth and have a consequent impact on algorithm execution times. Multicast communication has been among the most primitive group capabilities of any message passing in networks. It is central to many important distributed applications in science and engineering and fundamental to the implementation of higher-level communication operations such as gossip, gather, and barrier synchronisation. Existing solutions offered for providing multicast communications in WMN have severe restriction in terms of almost all performance characteristics. Consequently, there is a need for the design and analysis of new efficient multicast communication schemes for this promising network technology. Hence, the aim of this study is to tackle the challenges posed by the continuously growing need for delivering efficient multicast communication over WMN. In particular, this study presents a new load balancing aware multicast algorithm with the aim of enhancing the QoS in the multicast communication over WMNs. Our simulations experiments show that our proposed multicast algorithm exhibits superior performance in terms of delay, jitter and throughput, compared to the most well known multicast algorithms.     

基于工业无线网络性能评价的规划路径算法

针对路由节点查找消息路径的局限性,提出了一种网关设备规划消息路径的算法。该算法结合工业无线网络通信数据的规律性,在考虑时延、能耗、可靠传输和负载均衡方面的性能综合评价之后,找出一种路径组合,避免消息拥塞和干扰,提高通信性能。然后,设计了仿真实验来对比规划路径与AODV查找路径两种情况下的通信性能。实验结果证明,规划的消息路径下的通信性能更好。     

WMN中的干扰避免部分重叠信道分配算法

针对无线mesh网络(wireless mesh networks,WMN)中存在的信道干扰问题,提出一种基于部分重叠信道(partially overlapping channels,POC)的负载平衡且干扰避免的信道分配算法。通过基于Huffman树的通信接口分配方法连接邻居节点的接口;根据网络干扰情况,对链路进行迭代信道分配,使用静态链路调度保证网络连接;利用启发式算法优先为重要程度较高的链路分配无干扰时隙,对链路调度进行优化。仿真结果表明,在具有混合流量的WMN中,所提算法可以显著提升网络吞吐量,降低网络干扰与平均丢包率,改善网络性能。     

Linux内核HWMP序列号机制的研究与改进

为了提高混合无线网状网协议(hybrid wireless mesh protocol,HWMP)在工程应用中的鲁棒性,研究了Linux内核中的HWMP序列号机制.发现了由于“序列号有效”域在路由更新流程中处理不当引起的路径请求(path request,PREQ)死锁环问题,提出了删除“序列号有效”域的解决方案.该方案改变了HWMP的路由更新流程,消除了PREQ错误转发,进而消除了PREQ死锁环.在Linux内核中实现了该方案并进行了长时间的测试,表明了该方案的可行性和有效性.     

长链树状无线传感器网络中遗传蚁群路由优化算法

为提高长链树状无线传感器网络的服务质量(QoS),本文用云遗传蚁群网络算法对无线传感器网络路由进行优化.算法中将正向蚂蚁根据节点负载情况发现的可行路径作为遗传算法的初始种群进行染色体编码,用路径时延、跳数及链路质量定义的适应度函数对染色体进行评价;利用正态云发生器实现路径的交叉和变异操作,逆向蚂蚁对优化后的路径进行信息素更新.仿真结果表明该路由算法能够满足无线传感器网络的实时性、可靠性等方面的要求,实现了网络的负载平衡及拥塞控制机制.     

Complexity and design of QoS routing algorithms in wireless mesh networks

Quality of service (QoS) provisioning in wireless mesh networks (WMNs) is an open issue to support emerging multimedia services. In this paper, we study the problem of QoS provisioning in terms of end-to-end bandwidth allocation in WMNs. It is challenging due to interferences in the networks. We consider widely used interference models and show that except a few special cases, the problem of finding a feasible path is NP-complete under the models. We propose a k-shortest path based algorithmic framework to solve this problem. We also consider the problem of optimizing network performance by on-line dynamic routing, and adapt commonly used conventional QoS routing metrics to be used in WMNs. We find the optimal solutions for these problems through formulating them as optimization models. A model is developed to check the existence of a feasible path and another to find the optimal path for a demand; moreover, an on-line optimal QoS routing algorithm is developed. Comparing the algorithms implemented by the proposed framework with the optimization models shows that our solution can find existing feasible paths with high probability, efficiently optimizes path lengths, and has a comparable performance to the optimal QoS routing algorithm. Furthermore, our results show that contrary to wireline networks, minimizing resource consumption should be preferred over load distribution even in lightly loaded WMNs.     

802.11s中RM-AODV路径选择协议的研究

RM-AODV路径选择协议是IEEE 802.11s标准中HWMP路由选择协议的基础。不同于传统AODV协议在第3层使用IP地址路由和跳数作为路由metric,RM-AODV工作在第2层使用MAC地址和空时metric进行路径选择。为了适应无线mesh网络流量呈树状汇聚的特点,IEEE 802.11s标准还对RM-AODV进行树状先验式扩展。在典型无线mesh网络拓扑中通过仿真对RM-AODV的路径发现时间进行研究,进一步分析相对根节点的不同位置对路径发现时间的影响。     

Joint scheduling and routing algorithm with load balancing in wireless mesh network

Wireless mesh network (WMN) is a promising solution for last mile broadband internet access. Mesh nodes or mesh routers are connected via wireless links to form a multi-hop backbone infrastructure and improving throughput is the primary goal. While previous works mainly focused on either link level protocol design or complex mathematical model, in this paper, we investigate the performance gains from jointly optimizing scheduling and routing in a multi-radio, multi-channel and multi-hop wireless mesh network. Then, two optimization objectives are addressed by considering wireless media contention and spatial multiplexing. The first objective is to maximize throughput by exploiting spatial reuse while the second one is to ensure fairness among different links. We design a cross-layer algorithm by considering both MAC layer and network layer. Simulation results show that our joint optimization algorithm can significantly increase throughput as well as fairness.     

基于预测时延的无线mesh网络组播路由算法

通过对无线mesh网络的特性分析及其对路由的影响,提出一种基于预测时延的路由选择的组播路由算法,该算法通过选择从源节点到目的节点传输时延最小的路径,通过路径合并,形成组播路由树。这种路由算法具有低时延QoS保障能力,并具有局部修复能力。基于NS2对算法进行仿真,结果证明了算法的有效性。     

基于标识的无线Mesh网络接入认证协议

为解决无线Mesh网络节点高效、安全入网认证的问题,提出了一种新的基于标识认证的无线Mesh网络接入认证协议.该协议针对无线Mesh网络的特点,将标识认证体制引入到无线Mesh节点接入认证当中,并在标识认证的基础上一次性完成了入网节点的双向身份认证、网络认证和空口密钥的建立3个步骤.简化了认证的流程,减少了认证的时延,达到了分布式认证的效果,为大规模的节点接入提供了一种新的认证方案.通过BAN逻辑形式化方法证明了协议的安全性,通过效率分析说明了协议的高效性.     

SafeMesh: A wireless mesh network routing protocol for incident area communications

Reliable broadband communication is becoming increasingly important during disaster recovery and emergency response operations. In situations where infrastructure-based communication is not available or has been disrupted, an Incident Area Network needs to be dynamically deployed, i.e. a temporary network that provides communication services for efficient crisis management at an incident site. Wireless Mesh Networks (WMNs) are multi-hop wireless networks with self-healing and self-configuring capabilities. These features, combined with the ability to provide wireless broadband connectivity at a comparably low cost, make WMNs a promising technology for incident management communications. This paper specifically focuses on hybrid WMNs, which allow both mobile client devices as well as dedicated infrastructure nodes to form the network and provide routing and forwarding functionality. Hybrid WMNs are the most generic and most flexible type of mesh networks and are ideally suited to meet the requirements of incident area communications. However, current wireless mesh and ad-hoc routing protocols do not perform well in hybrid WMN, and are not able to establish stable and high throughput communication paths. One of the key reasons for this is their inability to exploit the typical high degree of heterogeneity in hybrid WMNs. SafeMesh, the routing protocol presented in this paper, addresses the limitations of current mesh and ad-hoc routing protocols in the context of hybrid WMNs. SafeMesh is based on the well-known AODV routing protocol, and implements a number of modifications and extensions that significantly improve its performance in hybrid WMNs. This is demonstrated via an extensive set of simulation results. We further show the practicality of the protocol through a prototype implementation and provide performance results obtained from a small-scale testbed deployment.     

基于WMN的无线视频监控系统的设计

结合无线Mesh网络(WMN)的技术特性和网络视频监控的新要求,提出了一种基于WMN的视频监控系统设计方案。监控终端通过摄像机和基于嵌入式Linux平台的视频服务器完成视频采集和压缩,利用WMN进行实时传输,监控中心在Mesh网络的覆盖范围内通过因特网进行视频数据接收,实现无线视频监控。实验测试结果表明,该系统播放流畅、实时性好,在无线视频监控中具有广泛的应用前景。     

Routing Internet traffic in heterogeneous mesh networks: Analysis and algorithms

In practical wireless mesh networks (WMNs), gateways are subject to hard capacity limits on the aggregate number of flows (in terms of bit rate) that they can support. Thus, if traffic is routed in the mesh network without considering those constraints, as well as the traffic distribution, some gateways or intermediate mesh routers may rapidly get overloaded, and the network resources can be unevenly utilized. To address this problem, in this paper we firstly develop a multi-class queuing network model to analyze feasible throughput allocations, as well as average end-to-end delay, in heterogeneous WMNs. Guided by our analysis, we design a Capacity-Aware Route Selection algorithm (CARS), which allocates network paths to downstream and upstream Internet flows so as to ensure a more balanced utilization of wireless network resources and gateways’ fixed connections. Through simulations in a number of different network scenarios we show that the CARS scheme significantly outperforms conventional shortest path routing, as well as an alternative routing method that distributes the traffic load on the gateway nodes to minimize its variance.     

The prediction of network efficiency in the smart grid

AMI is the core infrastructure of a smart grid and it is expected to be used for many industrial fields. The components of AMI generally include a smart meter, DCU, and MDMS. In such a system, the smart meter measures power consumption and DCU collects information from smart meters and send their data to MDMS. The MDMS is an end server to get information of the power usage and store its log and data. Since there are a lot of devices such as smart meters and DCUs in AMI, it is important to maintain the suitable number of them. In particular, it is necessary to calculate the proper number of DCUs for efficient management of AMI. In this paper, we suggest a way to predict the proper number of DCUs and this proposed method is useful to predict the total performance of heterogeneous AMI. The simulation results show that AMI is greatly influenced by the difference of performance between DCUs in the heterogeneous AMI.     

基于Grover搜索的无线Mesh网流量均衡路由算法

在无线Mesh网(WMN)应用中,用户通过Mesh网关接入到Internet,这种结构容易导致不同位置的Mesh路由器通过的流量不均衡,使部分路由器成为瓶颈,从而影响网络的性能和用户的服务质量(QoS)。针对这一问题,提出了一种基于Grover量子搜索算法的无线Mesh网流量均衡路由算法。算法中利用了量子计算的并行性,根据流量均衡函数模型构建了操作矩阵,通过Grover迭代获得流量均衡路径。仿真表明,算法选择的路径可以有效地平衡无线Mesh网流量,使每用户获得的最小带宽最大化,执行效率也优于同类算法。