Media-specific rate allocation in heterogeneous wireless networks

INTRODUCTION With the development of novel wireless tech- nologies and increasing available bandwidth, multi- media applications over wireless networks become attractive for both businesses and end users. Fast de- ployment of Wi-Fi HotSpots, increase in wireless coverage of remote habitable areas (Wi-Max, or wireless mesh networks), improved data services over the 2G cellular systems and the long awaited debut of 3G wireless services offer many potential and inter- operable communicatio…     

Joint rate control and scheduling for wireless uplink video streaming

INTRODUCTION Video streaming is becoming one of the major driving forces of next generation wireless networks. For the currently deployed cellular networks, the practical data rates are not enough to support full rate, high quality video applications. As a result, many research efforts have been devoted to adapting video content to reconcile the conflict between the high demand of video quality and the limited wireless communication resources among users. A large body of literature utiliz…     

基于最大独立集的多信道无线网络信道分配方法(英文)

提出了一种基于最大独立集的信道分配方法,以减少网络冲突提高网络性能.首先,建立信道分配模型,并通过所提出的低复杂度近似算法求取冲突图中的最大独立集序列;然后,以独立集间的冲突顶点数作为加权值,获得加权冲突图,通过加权冲突图,以最小化独立集间冲突为目标将链路分配至各信道;最后,每个节点根据本节点网卡中队列长度为已分配信道的链路分配网卡.仿真结果表明,该方法有效地提高了网络吞吐量,降低了端到端延时.     

无线自组织网络中带宽约束的分布式按需组播路由协议(英文)

为了满足无线自组织网络中的组播数据流带宽需求,提出了无线ad hoc网络中带宽约束的分布式按需组播路由协议.该协议中,每个节点的资源预留表将记录接入自身、邻居节点和隐蔽节点的数据流的带宽需求,然后从该节点的全部可用带宽中减去资源预留表中预留的带宽,计算出剩余的可用带宽,且BCMR在带宽约束的前提下分布式地搜索最短时延路径.仿真结果表明,BCMR在分组投递率和时延方面性能较好,能满足实时通信的要求,可用于低移动性的无线ad hoc网络组播应用中.     

Equation based rate control scheme for video streaming over wireless channels with link level ARQ

INTRODUCTION Video streaming applications generally require continuous high bandwidth guarantees as well as stringent bounds on delays and jitters (Shen et al., 2004; Hassan and Krunz, 2004). Providing video streaming with acceptable quality degradation over wireless channels is fraught with challenges due to the adverse influence of bandwidth limitation, time variation, high error rate, and so on (Etoh and Yo- shimura, 2005; Shen et al., 2004; Chen and Zakhor, 2004; Hassan and Krunz, …     

无线传感器网络中分簇定向扩散路由协议研究

结合定向扩散路由协议提出了一种新的分簇路由算法（CDD）．该算法在无线传感器定向扩算路由协议的基础上,引入分簇的概念,在大规模部署的传感器网络中,针对事件只发生在某一个局部检测区域的情况对传统的定向扩散路由协议进行改进,仿真证明了改进算法的有效性．     

无线Ad Hoc网络的路由协议及分类概述

无线移动Ad Hoc网络(Wireless Mobile Ad Hoc Networks)是随着无线通信技术的快速发展而出现的一种新型网络.它具有无中心结点限制、无有线介质限制、自组性、自愈性、高移动性和快速建立等优点,适合在复杂不确定的移动环境中应用.总括了Ad Hoc的基本概念、原理和现状,针对无线Ad Hoc网络特有的节能、QoS和安全三方面要求,对目前的Ad Hoc相关协议进行了概述、对比和分类, 有助于进一步研究.     

Joint channel and power allocation scheme for cognitive wireless networks

Cognitive radio (CR) is a promising technology deemed to improve the efficiency of spectrum utilization. This paper considers a spectrum underlay cognitive radio network, in which the cognitive users (CUs) are allowed to use the radio spectrum concurrently with the primary users (PUs) under the interference temperature constraint. We investigate the system performance by using the proposed joint channel and power allocation scheme under two transmit strategies to achieve higher data rates and performance diversity gain respectively. Simulation results show that the proposed scheme provides a significant improvement on the bit error rate (BER) performance and spectrum efficiency of a cognitive wireless network.     

无线传感器网络中基于网格的能量感知路由协议研究(英文)

通过建立无线传感器网络环境中的能耗模型, 研究了高效能耗以及由路径损耗模型不同带来的数据干扰问题. 采用二维网格分簇机制, 其中簇头选举算法基于节点的剩余能量和随机退避时间, 以一种高效且分散的方式使簇头在所有传感器节点中均匀轮换. 节点除了在传输和接收数据过程中消耗能量, 在干扰重传时也需要消耗额外的能量. 根据平面几何学, 通过分析和数学推导, 得出网络的总能耗与分簇机制中的网格结构直接相关的结论, 其中簇的大小决定传输范围, 节点距离决定路径损耗指数, 网络结构决定同时传输数据的节点产生的干扰总数. 通过分析和仿真实验, 提出了在无线传感器网络中优化的网格结构和对应的网格大小, 从而在最大化降低能耗和最小化总体冲突之间达成平衡.     

无线传感器网络中路由算法研究进展

传感器网络作为一种新型的具有广泛应用前景的无线自组网络，其有效路由协议是目前研究的热点。结合已有的研究，文章总结了传感器网络中路由协议的设计目标，详细阐述了目前提出的有代表性的路由协议和算法，针对传感器网络中的组播以及选播Qos路由算法设计，归纳总结了研究中需要解决的几大关键问题，提出了几点新的研究设想。     

Coping with handover effects in video streaming over cellular networks

The 3rd generation partnership project (3GPP) has defined the protocols and codecs for implementing media streaming services over packet-switched 3G mobile networks. The specification is based on IETF RFCs on audio/video transport. It also adds new features to achieve better adaptation to the mobile network environment. In this paper, we propose an algorithm for handover detection and fast buffer refill that is based on the existing feedback and signaling mechanisms. The proposed algorithm refills the receiver buffer at a faster pace during a limited time frame after a hard handover is detected in order to achieve higher video quality.     

无线传感器网络的SPIN协议研究

无线传感器网络是计算机科学技术的一个新的研究领域，是传感器技术、嵌入式计算技术、分布式信息处理技术和无线通信技术相结合的产物，具有广阔的理论研究和应用前景。本文对一种无线传感器网络路由协议SPIN-PP作了分析，并针对无线传感器网络的特点对其进行了一些改进工作，经NS2上的仿真结果表明这是一种有效的改进方案。     

A rate control scheme for H.264 video under low bandwidth channel

INTRODUCTION Rate control has been playing an increasing important role in real-time video communication. An encoder employs rate control to regulate output bit- streaming to meet certain channel bandwidth and buffer constraints while pursing high video quality. One fundamental problem in the encoder design is the selection of quantization parameter (QP) to maximize visual quality under constraints imposed by the computational complexity, delay, bandwidth and/or loss factors. At present…     

无线自组网路由协议分析

路由协议是无线自组网非常重要的协议之一,本文全面介绍了无线自组网的路由协议.先从面临的问题、设计的基本思想和要求这些方面阐述了无线自组网路由协议当前的基本情况;最后根据分类情况对路由协议进行分析和比较.     

无线ad hoc网络最小均方负载均衡路由算法

Routing algorithm is a challenge for a mobile ad hoc network (MANET), but current routing protocols for MANETsconsider the path with minimum number of hops as the optimal path to a given destination. This strategy does not balancethe traffic load over a MANET, and may result in some disadvantages such as creating congested area, depleting power fasterand enlarging time delay in the nodes with heavy duties. In this paper, we propose a routing scheme that balances the loadover the network by selecting a path based on its mean load-square, the proposed routing metric can reflect not only the loadof the path, but also the load distribution along the path. Simulation results show effectiveness of this routing scheme onbalancing the load over all nodes in the network.     

Experimental evaluation of an on-demand multipath routing protocol for video transmission in mobile ad hoc networks

We propose an on-demand multiparth routing algorithm in a mobile ad hoc network for video transmission and evaluate its real world performance in video streaming application. There have been a number of multipath routing protocols extended from AODV which is a well-known single path routing protocol. Multipath routing protocols indicate good performance in the reduction of route discovery latency and unnecessary routing packets in simulations. We show that the route establishment using source route lists provided by us (Hu and Johnson, 2002) can reduce the route discovery latency, select stable routes automatically, and work well for live video streaming without limitation of the hop count based approaches. We evaluate this proposed method compared with the original AODV by using eight laptop PCs and demonstrate live streaming experiments.     

无线Mesh网络中基于AOMDV多径路由算法的改进与实现

为了进一步提高无线Mesh网络的路由质量,多径路由技术逐渐成为近年来的研究热点。针对无线Mesh网络中多径路由算法AOMDV的不足进行改进,提出拥塞程度Metric的新判定依据,采用SRR算法分发数据流,建立叠加负载均衡机制。仿真结果表明,该路由机制能够有效提升网络性能。     

Adaptive swarm-based routing in communication networks

Swarm intelligence inspired by the social behavior of ants boasts a number of attractive features,including adaptation,robustness and distributed,decentralized nature,which are well suited for routing in modern communication networks.This paper describes an adaptive swarm-based routing algorithm that increases convergence speed,reduces routing instabilities and oscillations by using a novel variation of reinforcement learning and a technique called momentum.Experiment on the dynamic network showed that adaptive swarm-based routing learns the optimum routing in terms of convergence speed and average packet latency.     

Adaptive swarm-based routing in communication networks

INTRODUCTION Communication network management ibecoming increasingly difficult due to thincreasing size, rapidly changing topology, ancomplexity of communication networks. Currenrouting algorithms cannot adequately tackle sucnetworks. Centralized algorithms have scalabilitproblems; static algorithms have trouble keepinup-to-date with network changes; and othedistributed and dynamic algorithms havoscillation and s…     

Distributed media cooperation for enhanced video communication

INTRODUCTION According to yearly statistics the demand for multimedia traffic over computer networks is con- stantly on the increase (Nielsen//NetRatings, http:// www.nielsen-netratings.com/). Therefore, it is inevi- table that situations where different media streams will need to share communication resources will be- come commonplace. In such cases, it would be of interest to optimize the overall performance of the network. In other words, resources should be allo- cated across the com…