Gamma random waypoint mobility model for wireless ad hoc networks

Random waypoint (RWP) mobility model is widely used in ad hoc network simulation. The model suffers from speed decay as the simulation progresses and may not reach the steady state in terms of instantaneous average node speed. Furthermore, the convergence of the average speed to its steady state value is delayed. This usually leads to inaccurate results in protocol validation of mobile ad hoc networks modeling. Moreover, the probability distributions of speed vary over the simulation time, such that the node speed distribution at the initial state is different from the corresponding distribution at the end of the simulation. In order to overcome these problems, this paper proposes a modified RWP mobility model with a more precise distribution of the nodes' speed. In the modified model, the speeds of nodes are sampled from gamma distribution. The results obtained from both analysis and simulation experiments of the average speed and the density of nodes' speed indicate that the proposed gamma random waypoint mobility model outperforms the existing RWP mobility models. It is shown that a significant performance improvement in achieving higher steady state speed values that closely model the pre‐assumed average speeds are possible with the proposed model. Additionally, the model allows faster convergence to the steady state, and probability distribution of speed is steady over the simulation time. Copyright © 2012 John Wiley & Sons, Ltd.     

大规模移动自组网中稳定的分段式路由协议*

提出了大规模移动自组网中一种稳定的分段式路由协议,该协议中每个节点维护一个K跳邻域路由表来分段建立路由。模拟研究表明该协议性能良好,具有稳定性强和路由成功率高等特点。     

移动自组网中基于冻结技术的群组密钥更新

由于网络拓扑结构和成员关系的动态性、无线通信的不可靠性和各种延时的影响,移动自组网很容易受到各种安全威胁。现有的群组密钥管理方案很少考虑各种延时对密钥更新的影响,都难以应用到移动自组网中。该文提出了密钥更新冲突的概念,设计了基于冻结技术的群组密钥管理协议。当进行密钥更新时,通过簇头间的链式冻结机制实现对网络密钥的协调统一更新,以避免由于各种延时所产生的密钥更新冲突。模拟研究表明该协议大大降低了密钥更新失败率,减轻了密钥更新的计算开销。     

移动自组网络入侵检测中主动学习算法的应用

由于媒介开放、动态拓扑、交互及资源有限等特点,移动自组网络比传统网络更需要安全保障。介绍了一种集成入侵检测模型。在该模型中带监督异常检测的分类器基于支持向量机。同时,介绍了三种应用在该模型的基于池的主动学习算法。通过与传统的自学习算法比较,显示基于池的主动学习算法能有效地减少对训练样本的依赖,同时减少噪音数据对入侵检测系统性能的影响,适用于移动自组网络对于入侵检测系统高检测率、高抗噪能力和低计算延迟的要求。     

移动自组织网络中可扩展的定位符/标识符分离路由协议

In the traditional Internet Protocol (IP) architecture, there is an overload of IP semantic problems. Existing solutions focused mainly on the infrastructure for the fixed network, and there is a lack of support for Mobile Ad Hoc Networks (MANETs). To improve scalability. A routing protocol for MANETs is presented based on a locator named Tree-structure Locator Distance Vector (TLDV). The hard core of this routing method is the identifier/locator split by the Distributed Hash Table (DHT ) method, which provides a scalable routing service. The node locator indicates its relative location in the network and should be updated whenever topology changes . Locator space is organized as a tree-structure, and the basic routing operation of the TLDV protocol is presented. TLDV protocol is compared to some classical routing protocols for MANETs on the NS2 platform. Results show that TLDV has better scalability.     

Cross-layer signalling and middleware: A survey for inelastic soft real-time applications in MANETs

This paper provides a review of the different cross-layer design and protocol tuning approaches that may be used to meet a growing need to support inelastic soft real-time streams in MANETs. These streams are characterised by critical timing and throughput requirements and low packet loss tolerance levels. Many cross-layer approaches exist either for provision of QoS to soft real-time streams in static wireless networks or to improve the performance of real and non-real-time transmissions in MANETs. The common ground and lessons learned from these approaches, with a view to the potential provision of much needed support to real-time applications in MANETs, is therefore discussed.     

MANETs节点移动异质性对病毒传播影响

为了研究MANETs节点移动异质性对病毒传播的影响,对节点移动模型进行刻画,并基于元胞自动机理论建立MANETs病毒传播模型。在维持相同期望值而方差相异的情况下,研究节点移动速度,移动持续时间,停留时间和转动角度异质性对MANETs病毒传播的影响。结果表明：减少网络中节点移动异质性,可以有效抑制MANETs病毒传播。     

MDFNSSDP:基于最小转发节点覆盖集合的无线自组网服务发现协议

服务发现是在网络中寻找所需服务的技术,它是无线自组网的一项基本技术.本文提出了一个高效的无线自组网服务发现协议:MDFNSSDP.MDFNSSDP在转发服务需求包时能充分利用各项信息最大限度减少需要覆盖的2跳邻居节点数量,并选用最少的转发节点来覆盖这些2跳邻居,从而大大节约了信息包开销,提高了协议效率.MDFNSSDP能在一次服务发现会话中完成多个服务发现任务,并能保证服务发现会话的覆盖范围,这一点已经通过理论分析得到了证明.计算机仿真结果表明了MDFNSSDP的显著优越性.     

基于 IBE 的移动自组网安全接入机制

文中研究基于IBE的移动自组网安全接入机制,解决移动自组网拓扑动态变化、高时效性、快速切换等条件下的高效认证问题。对比分析各种认证机制的优缺点以及适用的环境,针对移动自组网内部的接入认证、动态组网认证、跨域认证,分别设计相关的认证流程及安全接入实现途径,保证骨干网、接入子网互联互通时的安全可控,为建设移动自组网安全防护体系提供理论依据和技术支撑。     

An efficient load balancing method for ad hoc networks

Routing is the most basic and essential operation of any ad hoc network. A mobile ad hoc network presents many challenges, because of the severe resource limitations such as dynamic and varying topology, lack of centralized control, insecure medium, and limited battery power, among others. Therefore, optimization and conservation is the key to success of any ad hoc network operation. In this paper, we propose and define 2 new metrics for ad hoc networks: bandwidth utilization ratio and load index. These metrics can be used as an indicator to measure and monitor the network usability and to improve its efficiency by efficient load distribution. They can be used to predict the additional load that can be accommodated in the network, without causing any congestion or overflows. We also propose a new load balancing routing scheme for ad hoc networks, called efficient load balancing method. This method tries to offset the load on different paths using load index as a metric. Load index is defined as a measure of a node's degree of involvement in the message routing process, which is indicative of its load. To make this algorithm efficient, we limit our routes to a few efficient ones only. This number of alternate routes used, out of the pool of all available routes, is defined as degree of distribution. Simulation results adequately prove the efficiency of proposed method, vis‐à‐vis 2 other load balancing approaches, and these are verified statistically at 99% confidence interval. A p × q factorial design is used to verify that simulation results are the actual measurements and not due to some unknown errors.