基于自适应蜂鸟算法的飞行自组网拓扑优化

针对飞行自组网(FANET)中无人机(UAVs)快速移动造成的网络拓扑管理困难问题,考虑实际场景中无人机位置变化引起的可用信道差异,该文提出一种自适应蜂鸟算法对网络拓扑进行优化。首先,建立一个针对分簇结构的无人机拓扑模型,并且形成一个以最小化簇数量、负载偏差和簇移动度为目标的优化问题。其次,通过调节人工蜂鸟的觅食动作、加入扰动变异的方式,提出寻优能力更强的自适应蜂鸟算法(ADHA)。然后,设计合理的蜂鸟个体编码方式,将拓扑优化的决策过程转化为自适应蜂鸟算法的寻优过程。最后,通过仿真验证所提算法的收敛性,并与基于其他群智能优化算法的拓扑优化方法进行对比。实验结果表明,所提算法得到的拓扑优化策略不仅能够有效减少网络拓扑的簇数量,而且能够得到负载均衡、结构稳定的簇群。     

Performance of PKI-based security mechanisms in mobile ad hoc networks

Security for ad hoc network environments has received a lot of attention as of today. Previous work has mainly been focussing on secure routing, fairness issues, and malicious node detection. However, the issue of introducing and conserving trust relationships has received considerably less attention. In this article, we present a scalable method for the use of public key certificates and their revocation in mobile ad hoc networks (MANETs). With the LKN-ad hoc security framework (LKN-ASF) a certificate management protocol has been introduced, bringing PKI technology to MANETs. In addition a performance analysis of two different revocation approaches for MANETs will be presented.     

一种Ad hoc网络中的协作路由方案及性能分析

该文提出了一种新的Ad hoc网络协作路由方案,通过邻居节点的协同发射,多点接收及路径总功率的比较,形成一条多点协作的能量最小路径。在节点可以获知邻居节点相对位置的假设下,通过在路由请求报文中携带路径总功率和协作簇信息,分布式地实现了路由方案。仿真结果表明协作路由比传统非协作的路由能量效率有30~50%的改善,同时通过协作节点的选择,选择最有效的节点进行协同发射,在能量效率略有下降的同时,降低了协作控制的开销和计算的复杂度。     

网络虚拟化互通技术

工业界和学术界提出了许多新的网络虚拟化技术来满足云计算环境对网络服务的需求.网络虚拟化技术的多样化使得云环境面临多种网络虚拟化技术共存的状况.然而,网络虚拟化技术间的差异会导致网络资源被分割成相互间不可通信的“孤岛”.为了解决这个问题,提出了网络虚拟化互通技术,分析了该技术的实现难点,并提出了基于软件定义网络的网络虚拟化互通架构Omni-Bridge,最后给出了Omni-Bridge的原型实现和功能验证.     

面向智能电网双向互动信息服务的通信组网方案设计

以建设智能电网对于智能用电的需求为出发点,研究了智能用电的关键技术以及智能用电新型服务,针对不同的用户设计了面向智能电网的双向互动信息服务系统以及通信组网方案。采用先进的双向互动通信技术、智能交互终端技术以及智能表计技术,为电网和用户之间的互动提供可靠的信息通道和网络支撑,并对应用层信息互动平台提出建设方案,构建了电网...     

MQBV: multicast quality of service swarm bee routing for vehicular ad hoc networks

Vehicular ad hoc networks (VANETs) are witnessing in recent years a rapid development for road transmissions and are considered as one of the most important types of next generation networks, in which drivers can have access anywhere and anytime to information. However, vehicles have to deal with many challenges such as the links failures due to their frequent mobility as well as limited degrees of freedom in their mobility patterns. In this paper, we propose a new quality of service multicast and multipath routing protocol for VANETs, based on the paradigm of bee's communication, called multicast quality of service swarm bee routing for VANETs (MQBV). The MQBV finds and maintains robust routes between the source node and all multicast group members. Therefore, the average end‐to‐end delay and the normalized overhead load should be reduced, while at the same time increasing the average bandwidth and the packet delivery ratio. Extensive simulation results were obtained using ns‐2 simulator in a realistic VANET settings and demonstrated the efficiency of the proposed protocol. Copyright © 2013 John Wiley & Sons, Ltd.     

Cross‐layer and cognitive QoS management system for next‐generation networking

Owing to limited wireless network resources, network applications must provide an adaptive quality‐guaranteed service to satisfy user requirements. Different applications are associated with different quality of service (QoS) concerns, as well as different QoS control parameters. This work presents an adaptive QoS algorithm by discussing the QoS specifications of three wireless access technologies, i.e. 3G, WiMAX and WiFi. Based on cross‐layer and cognition concepts, these environmental parameters are integrated with the sensing of spectral and received signal strength from a cognitive radio paradigm. An adaptive QoS algorithm is then proposed to select the optimal access network for services. Simulation results indicate that the proposed adaptive QoS algorithm outperforms available ones in real‐time applications. Compared with traditional algorithms, the proposed algorithm reduces not only the average delay time and jitter for VoIP services to 0.16 s and 0.09 ms, respectively, but also the packet loss ratio for high‐definition video streaming by 3.4%. Copyright © 2011 John Wiley & Sons, Ltd.     

基于定向天线的移动自组网路由协议研究

同等功耗下,定向天线能够产生更高的增益,提供更大的传输范围,提高网络的空间复用度和吞吐量,天线选择的方向性又降低了邻近结点之间的相互干扰,采用定向天线能够给移动自组网带来潜在性能的提高。对基于定向天线的移动自组网路由协议进行研究,简单介绍了定向天线,总结了引入定向天线产生的路由问题,对现有的一些典型定向路由协议进行了分类、介绍和比较,最后对引入定向天线带来的好处进行了分析。     

A distributed laxity-based priority scheduling scheme for time-sensitive traffic in mobile ad hoc networks

Characteristics of Mobile Ad hoc Networks such as shared broadcast channel, bandwidth and battery power limitations, highly dynamic topology, and location dependent errors, make provisioning of quality of service (QoS) in such networks very difficult. The Medium Access Control (MAC) layer plays a very important role as far as QoS is concerned. The MAC layer is responsible for selecting the next packet to be transmitted and the timing of its transmission. We have proposed a new MAC layer protocol that includes a laxity-based priority scheduling scheme and an associated back-off scheme, for supporting time-sensitive traffic. In the proposed scheduling scheme, we select the next packet to be transmitted, based on its priority value which takes into consideration the uniform laxity budget of the packet, the current packet delivery ratio of the flow to which the packet belongs, and the packet delivery ratio desired by the user. The back-off mechanism devised by us grants a node access to the channel, based on the rank of its highest priority packet in comparison to other such packets queued at nodes in the neighborhood of the current node. We have studied the performance of our protocol that combines a packet scheduling scheme and a channel access scheme through simulation experiments, and the simulation results show that our protocol exhibits a significant improvement in packet delivery ratio under bounded end-to-end delay requirements, compared to the existing 802.11 DCF and the Distributed Priority Scheduling scheme proposed recently in [ACM Wireless Networks Journal 8 (5) (2002) 455–466; Proceedings of ACM MOBICOM '01, July 2001, pp. 200–209].     

An efficient reliable broadcasting protocol for wireless mobile ad hoc networks

The mobile ad hoc network (MANET) has recently been recognized as an attractive network architecture for wireless communication. Reliable broadcast is an important operation in MANET (e.g., giving orders, searching routes, and notifying important signals). However, using a naive flooding to achieve reliable broadcasting may be very costly, causing a lot of contention, collision, and congestion, to which we refer as the broadcast storm problem. This paper proposes an efficient reliable broadcasting protocol by taking care of the potential broadcast storm problem that could occur in the medium-access level. Existing protocols are either unreliable, or reliable but based on a too costly approach. Our protocol differs from existing protocols by adopting a low-cost broadcast, which does not guarantee reliability, as a basic operation. The reliability is ensured by additional acknowledgement and handshaking. Simulation results do justify the efficiency of the proposed protocol.