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1.
For distributed multimedia applications the provision of system-wide quality of service (QoS) is essential. The quality-of-service architecture (QoS-A) developed at Lancaster University offers a framework to specify and implement the required performance properties of multimedia applications over integrated-service networks in a heterogeneous environment. The work addresses the problem of lower-level QoS as well as QoS support for multipeer multimedia applications operating in an open communication system. QoS filters have been developed to deal with the problems of heterogeneity in group communication environments. New challenges are also encountered in emerging mobile networks and user mobility; and recent developments in the Internet community highlight the need for appropriate QoS support mechanisms for multimedia applications. The paper describes how the QoS-A research at Lancaster University provides a flexible framework for the monitoring and control of multimedia communications across the broad range of computing systems and networks  相似文献   

2.
Filters: QoS support mechanisms for multipeer communications   总被引:2,自引:0,他引:2  
The nature of distributed multimedia applications is such that they require multipeer communication support mechanisms. The multimedia traffic needs to be delivered to end-systems, networks, and end-users in a form that they can handle while satisfying the constraints imposed by the multimedia application. Quality-of-service (QoS) mechanisms that can ensure full quality media playout at high-performance workstations, while at the same time providing appropriately filtered lower quality media for playout at other end-systems, are required. Existing multicast support mechanisms are deficient for this purpose, in a heterogeneous environment, because they work on a common denominator premise where the quality delivered depends on the least capable link or node involved in the multicast session. This paper begins by discussing video compression; it proposes and analyzes the use of filtering mechanisms as means of supporting disparate receiver capabilities and QoS requirements. The paper describes the implementation of a number of filtering mechanisms and highlights the communications architecture within which these mechanisms are built. This architecture constitutes a specific network topology and a new protocol family developed within a UNIX-like operating system  相似文献   

3.
For distributed multimedia services, it is essential that quality of service be guaranteed system-wide, including end systems, communication systems, and networks. Although many researchers have addressed issues of QoS management, little attention has so far been paid to the QoS management services in distributed multimedia services and applications. To address this deficiency, we have designed a layered model for end-to-end QoS management called the QoS management framework. Our framework, which is CORBA-based, includes a generic QoS MIB for the QoS parameterization of various multimedia services and the services needed to perform various QoS functions. A key component of this framework is the QoS management service object (QMSO), which orchestrates resources at endpoints, coordinating resource management across layer boundaries. Services such as translation, monitoring, admission, and negotiation are provided by the QMSO. To validate this concept, we have developed a QoS management system for managing and controlling the QoS of a distributed multimedia system called MAESTRO. The QoS management system has been implemented through CORBA objects and provides an interface to multimedia applications, which can be dynamic negotiation and renegotiation of QoS by users. Some performance results in QoS negotiation and renegotiation are also presented  相似文献   

4.
高速信息网络关键技术—成组广域广播与QoS控制   总被引:3,自引:2,他引:1  
张尧学  盖峰 《电子学报》1995,23(10):32-36
成组广域广播虚拟网络技术是高速信息网络的关键之一,它直接影响多媒体通信技术的发展与应用,本文综述介绍成组广域广播技术以及与此相关的网络服务品质QoS的控制,管理技术的现状,发展趋势以及研究方向。  相似文献   

5.
Quality of Service (QoS) measurement of multimedia applications is one of the most important issues for call handoff and call admission control in mobile networks. Based on the QoS measures, we propose a Generalized Stochastic Petri Net (GSPN) based model, called QoS-GSPN, which can express the real-time behavior of QoS measurement for mobile networks. QoS-GSPN performance analysis methodology includes the formal expression and performance analysis environment. It offers the promise of providing real-time behavior predictability for systems characterized by substantial stochastic behavior. With this methodology we model and analyze the call handoff and call admission control schemes in the different multimedia traffic environments of a mobile network. The results of simulation experiments are used to verify the optimal performance achievable for these schemes under the QoS constraints in the given setting of design parameters.  相似文献   

6.
Recent advances in distributed systems and transportable software and increasing demand for better quality of service (QoS) control in multiservice networks are driving a reexamination of network software architectures. We established the Comet (Control, Management, and Telemedia) Group at Columbia University's Center for Telecommunications Research to provide comprehensive understanding of network software architecture for the 1990s and beyond. This research focuses on developing new network architectures that support service creation, QoS control, and the joint allocation of computing and communications resources. This provides an opportunity to reconcile the perspectives of the computing and communication communities. Future multiservice (multimedia) networks will carry traffic such as video, audio, and computer data with diverse QoS requirements. Such networks will thus require that we develop ways to manage many physical and logical entities, services, and users  相似文献   

7.
With the fast growth of Internet services, the demand for wireless high speed and advanced multimedia communications is rapidly increasing. Initial multimedia services have already been offered in the second generation systems (2-G). Currently, the third generation systems (3-G) are being deployed and it will support up to 2 Mbps packet oriented data services. But it is expected that the demand for higher data rate and large variety of high quality services will increase further more. Therefore, it is mandatory for the fourth generation systems (4-G) to take each user's quality of service (QoS) control into account.In this paper, we firstly describe an overview on requirements and technical issues for the 4-G systems, and wireless QoS control issues considering End-to-End QoS control in the IP network. Next, we propose broadband wireless access method for the fourth generation mobile communication systems. The proposed method for downlink is based on MC-CDMA (Multi-Carrier Code Division Multiple Access) with Multi-Timeslot, in which total downlink resources are split into three aggregates according to the QoS classes in time domain. It is considered that one of the typical advantages for the MC-CDMA is the effect of frequency diversity. We evaluated the effect by computer simulation using ray-traced propagation model. Simulation results show that short-term fading can be relaxed. Furthermore, we propose Multi-Level (ML) ARQ as one of the link adaptation methods. Simulation results show that the proposed scheme has a good performance with throughput and average retransmission power.  相似文献   

8.
Wireless ATM networks: technology status and future directions   总被引:3,自引:0,他引:3  
The concept of “wireless ATM” (WATM), first proposed in 1992, is now being actively considered as a potential framework for new-generation wireless communication networks capable of supporting integrated, quality-of service (QoS) based multimedia services. In this review paper, we outline the technological rationale for wireless ATM, present a system-level architecture, and discuss key design issues for both mobile ATM switching infrastructure and radio access subsystems. The WATM radio access layer issues covered in this paper include: spectrum allocation; spectrum etiquette; modem technology; and medium access/data link control (MAC/DLC) protocols. Mobile ATM aspects such as ATM signaling extensions for handoff control, location management, and mobile QoS control are discussed. A summary of current wireless/mobile ATM technology development and standardization status is given, including an outline of our WATMnet prototype. The paper concludes with a discussion of future directions for wireless ATM technology such as Internet protocol (IP) integration and mobile multimedia terminals/applications  相似文献   

9.
Cross-Layer Design for Data Accessibility in Mobile Ad Hoc Networks   总被引:14,自引:0,他引:14  
Mobile ad hoc networks (MANET) are becoming an integral part of the ubiquitouscomputing and communication environment, providing new infrastructure formultimedia applications such as video phone, multimedia-on-demand, and others.In order to access multimedia information in MANET, Quality of Service (QoS)needs to be considered, such as high success rate to access multimedia data,bounded end-to-end delay, and others. In this paper, we present a dataaccessibility service for a group of mobile users to access desired data withhigh success rate. This accessibility service is only possible if we utilizeadvanced data advertising, lookup and replication services, as well as a novelpredictive location-based QoS routing protocol in an integrated fashion. Usingcross-layer design, we illustrate how the QoS routing protocol assists dataadvertising, lookup and replication services to achieve high data accesssuccess rate. Simulation results have shown that our design is successful ina dynamic MANET.  相似文献   

10.
In recent years, multicast communication is widely used by network providers to deliver multimedia contents. Quality of service (QoS) provisioning is one of the most important issues while transmitting multimedia contents using multicast. Traditional IP multicasting techniques suffer from reliability, scalability and have limitations to provide appropriate QoS for multimedia applications based on service level agreement (SLA). Nowadays, the advent of software defined networking (SDN), enables network providers to manage their networks dynamically and guarantee QoS parameters for customers based on SLA. SDN provides capabilities to monitor network resources and allows to dynamically configure desired multicasting policies. In this paper, we proposed a novel multicasting technique to guarantee QoS for multimedia applications over SDN. To deliver multimedia contents in an efficient manner, our proposed method models multicast routing as a delay constraint least cost (DCLC) problem. As DCLC problem is NP-Complete, we proposed an approximation algorithm using teaching–learning-based optimization to solve this problem. We evaluated our proposed method under different topologies. Experimental results confirmed that our proposed method outperforms IP multicast routing protocol, and it achieves a gain of about 25% for peak signal-to-noise ratio.  相似文献   

11.
This paper presents an ATM-based transport architecture for next-generation multiservices personal communication networks (PCN). Such “multimedia capable” integrated services wireless networks are motivated by an anticipated demand for wireless extensions to future broadband networks. An ATM compatible wireless network concept capable of supporting a mix of broadband ISDN services including constant bit-rate (CBR), variable bit-rate (VBR), and packet data transport is explored from an architectural viewpoint. The proposed system uses a hierarchical ATM switching network for interconnection of PCN microcells, each of which is serviced by high-speed, shared-access radio links based on ATM-compatible cell, relay principles. Design issues related to the physical (modulation), media access control (MAC), and data-link layers of the ATM-based radio link are discussed, and preliminary technical approaches are identified in each case. An example multiservice dynamic reservation (MDR) TDMA media access protocol is then considered in further detail, and simulation results are presented for an example voice/data scenario with a proportion of time-critical (i.e., multimedia) packet data. Time-of-expiry (TOE) based queue service disciplines are also investigated as a mechanism for improving the quality-of-service (QoS) in this scenario  相似文献   

12.
The emergence of wireless multimedia sensor networks (WMSN) has given birth to several civilian as well as defense applications. Some of the interesting applications employing low cost sensor nodes to manipulate rich multimedia content include traffic monitoring, border surveillance, smart homes, environment and habitat monitoring. Unlike the traditional sensor networks which are aimed at maximizing network lifetime by decreasing energy utilization, the main objective of WMSNs is optimized delivery of multimedia content along with energy efficiency. Multimedia communications in WMSNs, has stringent delay and high bandwidth requirement as compared to scalar data transfer in WSNs. Fulfilling these constraints in resource and energy constrained WMSNs is a huge challenge. In WMSNs, each layer of the protocol stack is responsible and fully involved in providing QoS guarantees. There is a need for new schemes at each layer of the protocol stack- from advanced coding techniques that reduce encoder complexity and achieve maximum compression to dynamic routing and MAC protocols that provide service differentiation and reduce end-to-end latency. In wireless sensor networks, where all layers have dependency on each other, QoS guarantees are possible through the cross layer interaction of different layers. This paper gives an overview of the different existing layered schemes in WMSNs, followed by a discussion on the significance and efficiency gains that can be achieved from cross layer interactions in WMSNs along with the review of the existing cross layer approaches. Finally, we identify the open research issues which have not been adequately addressed so far.  相似文献   

13.
Wireless ad hoc networks consist of nodes having a self-centrically broadcasting nature of communication. To provide quality of service (QoS) for ad hoc networks, many issues are involved, including routing, medium-access control (MAC), resource reservation, mobility management, etc. Carefully designed distributed medium-access techniques must be used for channel resources, so that mechanisms are needed to efficiently recover from inevitable frame collisions. For ad hoc wireless networks with a contention-based distributed MAC layer, QoS support and guarantee become extremely challenging. In this paper, we address this challenging issue. We first consider MAC and resource-reservation aspects for QoS support in one-hop ad hoc wireless networks. We propose two local data-control schemes and an admission-control scheme for ad hoc networks with the IEEE 802.11e MAC standard. In the proposed fully distributed local data control schemes, each node maps the measured traffic-load condition into backoff parameters locally and dynamically. In the proposed distributed admission-control scheme, based on measurements, each node makes decisions on the acceptances/rejections of flows by themselves, without the presence of access points. The proposed mechanisms are evaluated via extensive simulations. Studies show that, with the proposed schemes, QoS can be guaranteed under a clear channel condition while maintaining a good utilization. Discussions on applying the proposed schemes into multihop ad hoc networks are also included.  相似文献   

14.
The energy efficiency and quality of service (QoS) provisioning of wireless multimedia sensor networks (WMSNs) are two major issues that impact the application of such networks. Recent studies demonstrate that network performance can be greatly improved by involving multiple sinks. However, mainstream WMSN routing protocols are generally designed to account for a single sink. This paper proposes a QoS-aware multi-sink opportunistic routing (QMOR) to efficiently deliver multimedia information under QoS constraints for WMSNs. We begin with an optimal nodes selection problem to reduce redundant multimedia data. Then, we focus on selecting and prioritizing forwarder list to enhance transmission efficiency. Finally, the multi-sink-aware operations are integrated into an optimization opportunistic routing framework, with an objective to minimize energy consumption subject to delay and reliability constraints. Our simulation results demonstrate that the QMOR performs better than typical WMSN QoS routing algorithm, in terms of the video transmission quality and energy utilization efficiency.  相似文献   

15.
无线多媒体传感器网络QoS保障问题   总被引:10,自引:2,他引:8       下载免费PDF全文
孙岩  马华东 《电子学报》2008,36(7):1412-1420
 作为一种全新的信息获取和处理技术,无线多媒体传感器网络在军事、工业、商业、环保中具有广阔的应用前景.无线多媒体传感器网络感知媒体丰富、数据量大,处理任务复杂等显著特点,使其QoS保障问题的研究极具挑战性.本文就此问题,总结了无线多媒体传感器网络的QoS需求及其当前所面临的技术挑战.从MAC层、网络层、传输层、应用层、交叉层以及中间件六个方面,着重描述了无线多媒体传感器网络QoS保障的国内外研究进展.最后,分析了当前亟待解决的问题以及未来的研究趋势.  相似文献   

16.
Schmitt  Jens  Wolf  Lars  Karsten  Martin  Steinmetz  Ralf 《Telecommunication Systems》1999,11(1-2):105-125
In communication systems there are two worlds at the moment: Internet and ATM. Both possess Quality of Service (QoS) architectures which shall allow them to integrate services of data and telecommunications formerly performed by separate infrastructures. We believe that none of them will be able to oust the other. That means both will exist for at least the middle-term future. Therefore, an interaction between both appears to be necessary, especially in the field of distributed multimedia applications where both worlds meet first. In order to perform gracefully, distributed multimedia applications require a certain QoS provision, in particular from the communication system. Thus, for such applications the existence of heterogeneous IP/ATM networks makes the interaction between Internet and ATM QoS architectures an important issue. In this article a taxonomy of interaction models for the Internet and ATM QoS architectures is developed. We do not let our view be restricted by existing approaches for the interaction between ATM and Internet. Instead we will derive more unconventional models by regarding the possible communication patterns based on different topological variants for heterogeneous IP/ATM networks. The investigation is driven by applications' communication requirements. This is accomplished by examining possibly interacting applications and their communication patterns. The interaction models are contrasted and compared to each other and their assumptions and implications are shown. The derived taxonomy of models allows us to classify proposed approaches for the interaction of Internet and ATM QoS architectures. Thereby we are able to identify the basic assumptions of these approaches and their corresponding restrictions.  相似文献   

17.
1 Motivation Nowadays , the QoS provided by the wideband IPnetwork starts at an edge-router and ends at anotheredge-router .Therefore ,the trunk QoSisfinished,suchas RSVP[1]and DiffServ[2].In order to complete theend-to-end QoS,the mechanism of entrance QoS (thebandwidth controller) is introduced. As Fig.1 shows ,if the bandwidth controller circledby the dashed frame is not used,the Ethernet is con-nected with the router directly through 100 Mbit/sbandwidth. Then this router is connect…  相似文献   

18.
The convergence of wireless systems with multimedia services is the challengeof future generation wireless networks. The large variety of QoS requirementsof different media as well as the maintenance of synchronization of thedifferent streams to be presented at receiver, demand from the Data link layersome extra functionalities. In this paper, we present an enhanced approach forthe efficient management of multimedia applications in third-generationwireless networks. We advocate the use of multiple connections, one for eachtraffic component of the application, as the effective solution for thetransport of multimedia applications in future-generation wireless networks.The effectiveness of this scheme is guaranteed by providing a new link controltechnique that works on top of a PRMA-type access protocol which jointlymanages different streams of a multimedia application. For this purpose, wepropose a two-level priority mechanism (static and dynamic priorities)specified by higher protocol layers for link activation, channel access, andadmission control procedures specific to a multimedia application and foroptimizing the sharing of radio channel resources and management of thereservation queue at the base station. We expect this priority-based mechanismto perform well, especially during periods in which system traffic load ishigh, and to react well to the deterioration of multimedia service quality,in terms of both QoS parameters and the synchronization of its trafficcomponents.  相似文献   

19.
Home wireless local area networks (LANs) will carry diverse multimedia applications such as data, video, voice, and time sensitive control information. To enable quality delivery of such applications, these networks should incorporate an efficient quality of service (QoS) support mechanism. However, existing home wireless LANs do not provide support for multimedia applications. In this paper, we introduce our software based solution that provides QoS support for voice, video and data while using existing wireless home networks. The experimental results we have obtained provide evidence that our solution provides QoS support for multimedia applications.  相似文献   

20.
One of the major challenges in supporting multimedia services over Internet protocol (IP)-based code-division multiple-access (CDMA) wireless networks is the quality-of-service (QoS) provisioning with efficient resource utilization. Compared with the circuit-switched voice service in the second-generation CDMA systems (i.e., IS-95), heterogeneous multimedia applications in future IP-based CDMA networks require more complex QoS provisioning and more sophisticated management of the scarce radio resources. This paper provides an overview of the CDMA-related QoS provisioning techniques in the avenues of packet scheduling, power allocation, and network coordination, summarizes state-of-the-art research results, and identifies further research issues.  相似文献   

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