抗毁WDM网中支持QoS的选路和波长分配算法

该文首先探讨了抗毁WDM网中支持QoS的分层图模型,在此基础上提出一种抗毁WDM网中支持QoS的选路和波长分配算法。该算法根据上层业务不同的QoS要求,对其光路建立请求区别对待,以满足它们不同的阻塞率和恢复率要求。计算机仿真结果表明该算法既满足了上层业务不同的QoS要求,同时又充分利用了有限的网络资源,使全网的平均阻塞率降低。     

Efficient protocols for multimedia streams on WDMA networks

This paper introduces a new approach to integrate different types of medium access control (MAC) protocols into a single wavelength-division-multiplexing (WDM) network system. The WDM network is based on a passive star coupler, and the purpose of integrating different MAC protocols is to efficiently accommodate various types of multimedia traffic streams with different characteristics and quality of service demands. Our integrated MAC protocol is termed multimedia wavelength-division multiple-access (M-WDMA). Three types of multimedia traffic streams are considered in this paper: constant-bit-rate traffic and two classes of variable-bit-rate traffic. Accordingly, three tunable transmitters and one fixed home channel receiver are used in the design of each WDM node. The transmitters transmit the three types of multimedia traffic streams in a pipeline fashion so as to overcome the tuning time overhead and to support parallel transmissions of traffic streams that emerge simultaneously. We further incorporate a dynamic bandwidth allocation scheme that dynamically adjusts the portions of bandwidth occupied by the three types of traffic streams according to their demands. Consequently the M-WDMA protocol achieves high utilization and efficiently adapts to the demands of the multimedia streams so as to guarantee their QoS. The performance of the M-WDMA is evaluated through a simple analytical model and extensive discrete-event simulations. It is shown that the M-WDMA can satisfy the QoS requirements of various mixes of multimedia traffic streams even under very stringent requirements. Moreover, we show that the M-WDMA outperforms conventional MAC protocols for WDM networks. As a result, we expect M-WDMA to be a good multimedia MAC candidate protocol for future-generation WDM networks.     

TPGF: geographic routing in wireless multimedia sensor networks

In this paper, we propose an efficient Two-Phase geographic Greedy Forwarding (TPGF) routing algorithm for WMSNs. TPGF takes into account both the requirements of real time multimedia transmission and the realistic characteristics of WMSNs. It finds one shortest (near-shortest) path per execution and can be executed repeatedly to find more on-demand shortest (near-shortest) node-disjoint routing paths. TPGF supports three features: (1) hole-bypassing, (2) the shortest path transmission, and (3) multipath transmission, at the same time. TPGF is a pure geographic greedy forwarding routing algorithm, which does not include the face routing, e.g., right/left hand rules, and does not use planarization algorithms, e.g., GG or RNG. This point allows more links to be available for TPGF to explore more routing paths, and enables TPGF to be different from many existing geographic routing algorithms. Both theoretical analysis and simulation comparison in this paper indicate that TPGF is highly suitable for multimedia transmission in WMSNs.     

Efficient delivery of multimedia streams over broadband networks using QOAS

Quality Oriented Adaptation Scheme (QOAS) is compared against other adaptive schemes such as TCP Friendly Rate Control Protocol (TFRCP), Loss-Delay-based Adaptation Algorithm (LDA+), and a nonadaptive (NoAd) solution when streaming multiple multimedia clips with various characteristics over broadband networks. Streaming efficiency is assessed in terms of loss rate, bandwidth utilization, number of concurrent clients and end-user perceived quality. Simulation results show that using QOAS a significantly higher number of simultaneous clients can be served than when using the other schemes given a target average end-user quality. This is while having higher bandwidth utilization. Testing results also indicate that higher performance is achieved when streaming to the same number of clients using QOAS than when other solutions are used.     

无线多媒体传感器网络中一种改进路由算法

随着网络负载增加,经典的TPGF( Two-Phase geographic Greedy Forwarding)算法难以找到节点分离路径,会导致网络吞吐量、投递率以及端到端时延性能下降。此外,当网络拓扑变动不大时, TPGF中每条路径所包含节点要消耗比其他节点更多的能量,会导致其过快死亡,从而影响网络性能。为此,将联合网络编码技术引入 TPGF,提出一种编码与能量感知的 TPGF 路由算法( NE-TPGF)。该算法综合考虑节点的地理位置、编码机会、剩余能量等因素,同时利用联合网络编码技术进一步扩展编码结构,充分利用网络编码优势来建立相对最优的传输路径。仿真结果表明, NE-TPGF能够增加编码机会,提高网络吞吐量和投递率,降低端到端时延,并且还有利于减少和平衡节点的能量消耗。     

Delay constraint multipath routing for wireless multimedia ad hoc networks

According to the disadvantages of real time and continuity for multimedia services in ad hoc networks, a delay constraint multipath routing protocol for wireless multimedia ad hoc networks, which can satisfy quality of service (QoS) requirement (QoS multipath optimized link state routing [MOLSR]), is proposed. The protocol firstly detects and analyzes the link delay among the nodes and collects the delay information as the routing metric by HELLO message and topology control message. Then, through using the improved multipath Dijkstra algorithm for path selection, the protocol can gain the minimum delay path from the source node to the other nodes. Finally, when the route is launched, several node‐disjoint or link‐disjoint multipaths will be built through the route computation. The simulation and test results show that QoS‐MOLSR is suitable for large and dense networks with heavy traffic. It can improve the real time and reliability for multimedia transmission in wireless multimedia ad hoc networks. The average end‐to‐end delay of QoS‐MOLSR is four times less than the optimized link state routing. Copyright © 2014 John Wiley & Sons, Ltd.     

基于QoS的动态组播路由算法

在分析了网络中基于QoS的组播路由问题的基础上,本文提出了一种新的动态算法,并进行了实验和分析,文中构造的路由方案成功地解决了当网络中存在多个组播及组播节点动态变化情况下的QoS路由选择问题,此方案不仅保证了带宽,端到端延时和延时抖动,优化了路由树的代价,而且有效地控制了算法的复杂性并可适用于大规模的网络中。     

QoS-based multicast routing optimization algorithms for Internet

Most of the multimedia applications require strict Quality-of-Service （QoS） guarantee during the communication between a single source and multiple destinations. The paper mainly presents a QoS Multicast Routing algorithms based on Genetic Algorithm （QMRGA）. Simulation results demonstrate that the algorithm is capable of discovering a set of QoS-based near optimized, non-dominated multicast routes within a few iterations, even for the networks environment with uncertain parameters.     

Distributed quality of service routing protocol for multimedia traffic in WiMedia networks

Ultra-wideband (UWB) technology has emerged as a solution for the wireless interface between medical sensors and personal servers in future telemedicine systems. The WiMedia Alliance has specified a distributed medium access control protocol based on UWB for high-rate WPANs. In the cases of some applications, data traffic between the source device and destination device is transmitted via one or more intermediate links before it reaches the destination device. However, when all data frames do not transmit in the current DRP reservation block, a relay device cannot transmit the received data frame from the source device in the current DRP policy, until the next DRP duration reserved for forwarding to the destination device begins. This policy increases end-to-end latency between the source device and destination device significantly. Therefore, in this paper, we propose a novel reservation-based routing protocol to minimize the end-to-end delay between source and destination. The proposed routing protocol utilizes the number of medium access slots and hop-count to decide the optimal route between the source device and destination device. The simulation results show that the proposed protocol can enhance the throughput and delay performance and improve energy efficiency by minimizing the packet drop and collision.     

A survey and analysis of multipath routing protocols in wireless multimedia sensor networks

The main objective of this research is to conduct a performance analysis of various multipath routing protocols in wireless multimedia sensor networks for the efficient transmission of the image, audio and video data. To provide efficient routing for the large sized multimedia content, various multipath routing protocols such as energy-aware routing, QoS based routing and geographical routing methods are analyzed. In this analysis, the efficient routing techniques including geographical routing techniques such as GPSR, DGR, PW-DGR presented for wireless multimedia sensor networks are studied and the performance of each technique is evaluated to determine the efficient multipath routing technique. Comparisons are made for evaluated protocols and it is proved that the PW-DGR provides better routing performance for the multimedia data. The findings of the research also show that the PW-DGR method efficiently overcomes the routing problems such as energy bottleneck problem, energy-hole, reduced network lifetime and high delay in packet transmission.     

Overall reliability determination of computer networks with hierarchical routing strategies

This paper determines the overall reliability of a computer network in which hierarchical routing strategies are used for the communication between its nodes.An exact method is presented which is followed by three fast computer techniques corresponding to three different routing policies. The first two give the exact value for the overall reliability while the third provides a lower bound which is very close to the exact reliability value. The main advantages of these techniques are the important savings in computation time and available memory. The developed algoriths are very useful in the overall reliability evaluation of large networks or many interconnected subnetworks.     

Representations and routing for Cayley graphs [computer networks]

It is shown that all finite Cayley graphs can be represented by generalized chordal rings (GCR). An example Borel Cayley graph is used to illustrate the generation of GCR representations. A sufficient condition is given for the representation of a Cayley graph as a chordal ring (CR). With the integer labeling of GCR representations, a straightforward, progressive routing algorithm based on table look-up is summarized     

Multicasting multimedia streams in IEEE 802.11 networks: a focus on reliability and rate adaptation

Multicasting multimedia streams in IEEE 802.11 wireless LANs has two issues: reliability and rate adaptation. We address these issues by proposing two mechanisms that augment the current multicasting standards in a backward-compatible fashion. Semi-reliable multicasting (SRM) selects a leader who sends feedback information to lessen the reliability problem of multicast frames. Probing-based auto-rate fallback (PARF) allows the multicast source to adjust the bit rate depending on the link conditions of multicast recipients. Comprehensive simulation experiments reveal that SRM + PARF achieves reliability and link efficiency close to those of an omniscient multicasting framework.     

Multicast routing for multimedia communication

The authors present heuristics for multicast tree construction for communication that depends on: bounded end-to-end delay along the paths from source to each destination and minimum cost of the multicast tree, where edge cost and edge delay can be independent metrics. The problem of computing such a constrained multicast tree is NP-complete. It is shown that the heuristics demonstrate good average case behavior in terms of cost, as determined by simulations on a large number of graphs     

基于蚁群优化的无线多媒体传感器网络区分服务路由

无线多媒体传感器网络中存在多种类型的数据,而且这些数据的服务质量需求并不相同。针对这种情况,提出一种基于蚁群优化的区分服务路由协议（DSACO, differentiated service and ant colony optimization based routing protocol）。DSACO在网络分层的基础上通过限制蚂蚁的搜索范围以减少建立路由的时间和能量消耗,对不同服务质量需求的数据采用区分服务路由以满足不同类型数据的服务质量需求。仿真结果表明,新协议能够为多媒体数据的传输提供更好的QoS保障,在数据传输的平均时延、分组丢失率和能量消耗上优于已有路由协议。     

MM-DSR: Multipath QoS routing for multiple multimedia sources over Ad Hoc mobile networks

Nowadays, services over Mobile Ad hoc Networks (MANETs) are becoming more used, and multimedia services such as video-streaming applications are more demanded. Hence, it is necessary to provide end-to-end QoS over MANETs, although it poses a challenging problem due to the ephemeral structure of these networks. MM-DSR (Multipath Multimedia Dynamic Source Routing) is a multipath routing protocol DSR-based merged with a cross-layer algorithm which is able to provide QoS for multiple sources of video over IEEE 802.11b Ad Hoc networks. The weaknesses of the system with plain DSR and IEEE 802.11b have been analysed and work has been done in order to improve the throughput and the final user quality. The performance of video-streaming applications has been improved under high traffic load conditions over mobile Ad Hoc networks.     

基于QoS的无线传感器网络感知调度协议

针对大规模随机部署传感器网络的节点密度不均匀性和不同应用对事件监测时延的不同需求,为提供全网可调的监测时延保障,设计了面向事件监测应用的全网能耗均衡的自适应分布式感知调度协议(ADSSP),仿真结果表明:相对于随机感知调度协议,ADSSP能获得更低的平均监测时延,在满足相同的平均监测延迟的前提下延长了30%的网络生存时间.     

A fuzzy geographical routing approach to support real-time multimedia transmission for vehicular ad hoc networks

Vehicular ad hoc networks known by their greatly active topology have given rise to new challenges related to routing protocols, issues of less concern in infrastructure-based networks or even in mobile ad hoc networks. Indeed, the high revocability of network topology makes the satisfaction of driver’s requirements very arduous, especially with multimedia applications that need strict quality of service (QoS) support. The main purpose of this paper is to promote real time video traffic by maximizing user gratification while keeping a good QoS. Thus, based on the well-known greedy perimeter stateless routing (GPSR) protocol, we propose a new approach called fuzzy geographical routing (FzGR) that incorporates two fuzzy logic usages. The first takes into consideration three input parameters of QoS: the delay, the size of buffer and the throughput, while it outputs a single relevant metric to prioritize the next-hop with lower concern. The other fuzzy system aims at preserving the concept of basic GPSR by considering the distance measure between each next-hop and the final destination. The proposal has been evaluated and compared to the GPSR using a rigorous metrics analysis regarding QoS and quality of experience. Our extensive experimental results using several simulators (e.g., NS-2, VanetMobiSim and Evalvid), show that FzGR has the ability to increase the performance of the network.

     

多媒体通信的多播路由算法

在多媒体通信网的实际应用中,多播(multicasting)技术日显重要,在实际网络中,网络节点具备不同的多播能力,有些节点不具备多播能力,而具备多播能力的节点要限制其复制信息的数量,即节点多播能力受限,该文用节点的度约束来表示每个节点的多播能力;此外网络中的很多业务要求信息从源节点传送到目的节点的时延受限;因此该文研究带度约束和时延约束的多播路由问题,给出了一种Lagrange松弛法,能够较好地解决这类问题。     

多媒体通信中的多点路由问题

多点通信是网络支持多媒体业务的关键技术之一。本文在不同优化选路准则下,结合当前应用背景介绍了基于最短路径和共享树的多点路由算法及其应用环境和性能分析,在此基础上对有关协议进行了讨论,最后结合多媒体业务的特征分析了多点路由算法的几个发展方向,以期对多点通信的路由问题最近和将来的研究给出必要的背景。