Delivery Of Multimedia Services Research Articles

Satellite radio interface and radio resource management strategy for the delivery of multicast/broadcast services via an integrated satellite-terrestrial system

A variety of hybrid systems combining third-generation mobile communication networks with broadcast systems have been proposed for the delivery of multimedia broadcast multicast services (MBMS) to mobile users. The article discusses one of these alternatives, which involves the use of a geostationary satellite component for MBMS delivery. In particular, it proposes a radio access scheme for the satellite component of the system that features maximum commonalities with the standardized T-UMTS WCDMA-based interface. The ultimate advantages of this approach are more efficient delivery of MBMS as far as the mobile network operator is concerned. The required adaptations at the interface layers are described, and the radio resource management strategy that fulfills the particular requirements of the satellite system is presented.

Seamless User-Level Handoff in Ubiquitous Multimedia Service Delivery

Advancing mobile computing technologies are enabling “ubiquitous personal computing environment”. In this paper, we focus on an important problem in such environment: user mobility. In the case of user mobility, a user is free to access his/her personalized service at anytime, anywhere, through any possible mobile/fixed devices. Providing mobility support in this scenario poses a series of challenges. The most essential problem is to preserve the user's access to the same service despite changes of the accessing host or service provider. Existing system-level mobility solutions are insufficient to address this issue since it is not aware of the application semantics. On the other hand, making each application to be mobility-aware will greatly increase the development overhead. We argue that the middleware layer is the best place to address this problem. On one hand, it is aware of application semantics. On the other hand, by building application-neutral mobility functions in the middleware layer, we eliminate the need to make each application mobility-aware. In this paper, we design a middleware framework to support user mobility in the ubiquitous computing environment. Its major mobility functions include user-level handoff management and service instantiation across heterogeneous computing platforms. We validate the major mobility functions using our prototype middleware system, and test them on two multimedia applications (Mobile Video Player and Mobile Audio Player). To maximally approximate the real-world user-mobility scenario, we have conducted experiments on a variety of computing platforms and communication paradigms, ranging from T1-connected high-end PC to handheld devices with wireless networks. The results show that our middleware framework is able to provide efficient user mobility support in the heterogeneous computing environment.

S‐UMTS access network for broadcast and multicast service delivery: the SATIN approach

AbstractThis paper proposes a complete satellite access network solution for multimedia broadcast multicast service (MBMS) delivery based on T‐UMTS standards. First, the benefits of MBMS delivery via satellite (SAT‐MBMS) for both S/T‐UMTS network operators are shown with market and business analysis. A new integrated S/T‐UMTS architecture for MBMS delivery is proposed featuring an intermediate module repeater (IMR) for coverage of urban areas. The architectural options of IMR and terminals are discussed considering the relevant cost and complexity. The IMR propagation channel conditions are investigated and a new propagation channel model is proposed. The potential of advanced coding schemes such as the layered coding technique to tackle the channel variations in broadcast/multicast environment is outlined. The functional and protocol architecture are defined along with the interface between the satellite access network and the UMTS core network. Required modifications on the terrestrial access scheme sub‐layers to support MBMS data are investigated and the relevant logical, transport and physical channels are selected. Based on the channel selection and the point‐to‐multipoint service nature, we define a generic radio resource management (RRM) strategy that takes into account both QoS and GoS requirements. The efficiency of the proposed solutions is evaluated in the presented simulation results, advocating the feasibility of the overall approach. Copyright © 2004 John Wiley & Sons, Ltd.

Design of a multimedia content-delivery service architecture for 3rd generation networks

The Virtual Home Environment (VHE) has been introduced as an abstract concept enabling users to access and personalize their subscribed services whatever the terminal they use and whatever the underlying network used. Much effort is currently being spent upon the challenging task to provide an architectural solution and an implementation of the VHE, providing ubiquitous service availability, personalized user interfaces and session mobility while users are roaming or changing their equipment. In this paper we present a multimedia delivery service, one of the VHE services selected to demonstrate its features, showing its interconnection with the so far defined VESPER VHE architecture.

On selecting a technology evolution path for broadband access networks

The rapid growth in the number of Internet users has accelerated the use of high-speed Internet access services, including broadband multimedia services. In the delivery of broadband multimedia services to end-users, it is necessary to build a high-speed backbone and access network. To construct a broadband access network, several alternative technologies including xDSL, CATV, and FTTx have been suggested and implemented in telecommunication networks. However, even if a technology is proven to be optimal for the current environment, it can be deteriorated by the elapse of time or the advent of new challenging technologies in the future. In this article, we concentrate on the selection of an evolution path for broadband access networks. We developed an optimization model for selecting the best technology and evolution path with the minimum total cost. The problem can be formulated as a mixed integer programming model. With a scenario for demands and cost factors, we find the optimal evolution path by solving our model with the CPLEX program and illustrate some sample paths for the broadband access network evolution plan. Once the cost and the demand are defined in detail to reflect the real-world case, our model can be useful to generate a practical technology evolution plan for broadband access networks in real-world applications.

Advanced service creation using distributed object technology

Rapid technological developments are taking place in computing and telecommunications that provide a wide range of opportunities for the delivery of new advanced multimedia services (telematic services). In this context information networking has a central role, and telecommunications service engineering emerges as an important new scientific discipline. This article examines important issues that underpin the creation of telematic services in a highly competitive environment of service provisioning. The starting point is the proposal of a telecommunications service engineering framework consisting of a service development methodology, a service creation environment, and a service support environment, that considers telematic services as distributed object-oriented applications operating on distributed object platforms. Then the article focuses on the presentation and examination of a complete methodology for the development of telematic services, that "covers" in a systematic and structured manner the entire service creation process. Finally, the proposed methodology is validated by applying it to the design and development of a complex representative telematic service.

QoS management in programmable networks through mobile agents

In delivering multimedia services, quality of service represents a crucial commitment to be satisfied. Very often it has been considered only from a theoretical point of view, leaving any implementation details out of the discussion, mainly for the lack of concrete possibilities to execute its control and management effectively. Recent technological developments in the networking and distributed programming fields are now opening new challenging scenarios towards the negotiation and guarantee of QoS in the delivery of multimedia services through the network. Active or programmable networks are becoming a reality, and the migration of software components among network nodes seems to be the direction pursued by most of network manufactures. Mobile software agents represent a very attractive approach to the distributed control of computer networks and a valid alternative to the implementation of strategies for the management of QoS. In this paper, we present our approach to QoS management through mobile agents. The potentiality of this approach is shown through two application examples. The first one focuses on resource reservation through RSVP in an int-serv scenario, while the second one shows how to provide QoS to aggregated traffic flowing through a virtual network.

A new adaptive MAC layer protocol for broadband packet wireless networks in harsh fading and interference environments

A new medium-access protocol is proposed for sharing a high-speed radio channel among a number of small wireless packet-access units, some of which may be stationary and some of which may be within moving vehicles. Such a system could provide fixed-point pedestrian and remote users with wireless access to CPU and database resources of an underlying asynchronous transfer mode (ATM) wireline network, essentially extending the ATM bandwidth-upon-demand interface directly to the wireless units and enabling delivery of multimedia services (albeit at the lower peak rate afforded by the radio channel). A primary goal of the proposed medium-access protocol is the pre-delivery of a signal from each packet-access unit as needed to rapidly compute the weights needed by a base station's adaptive array processor or a space-time processor, thereby protecting the packet flow in each direction from the effects of both multipath propagation and adjacent channel interference arising in neighboring radio cells. An impairment-robust direct sequence spread-spectrum-based polling signal is invoked to stimulate a pilot tone from a given remote immediately prior to packet transfer in either direction, thereby permitting the base station to determine a good set of antenna element combining or power splitting weights to be used for that packet. Reasonable approximations are invoked to study the performance of the proposed protocol and the link utilization efficiency and average message delay are found. By proper choice of protocol parameters, a radio resource utilization efficiency of about 95% is readily achieved. The accuracy of the approximations is confirmed by extensive computer simulations.

Trouble Management for Multimedia Services in Multi-Provider Environments

As telecommunications and computers evolve, multimedia services are being increasingly deployed over a variety of organizational and technology domains. Customer requirements and the competitive market mean that the delivery of multimedia services at a guaranteed level of quality can play a significant role in differentiating between service providers. In order to meet such quality of service requirements, service providers need to be supported by trouble management capabilities suitable for today's heterogeneous environment. This paper presents an integrated network and service trouble management system that has been designed for such an environment within the framework of the European ACTS project FlowThru. The FlowThru Service Quality Assurance System has been developed using TINA and TMN concepts and TeleManagement Forum business processes in order to support service providers with the necessary infrastructure, models and mechanisms for automated end-to-end trouble management in a multi-domain environment.

Delivery of digital video and other multimedia services (<1 Gb/s bandwidth) in passband above the 155 Mb/s baseband services on a FTTx full service access network

For low cost passive optical access networks (PON), we have studied the downstream delivery of an additional >1 Gb/s in the passband above the 155 Mb/s baseband services. Both signals are transmitted on the same fiber using a single transmitter and a single receiver within the power budgets of ITU-T G983. Although our study has used broadcast DSS digital video services for the passband that delivers about 1.2 Gb/s, the passband bandwidth can be used for any broadcast or switched multimedia services, i.e., digital video, data, and audio. For switched services, the baseband upstream will be the return path. Furthermore, the passband can be used to provide a dedicated bandwidth to any subscriber. The passband approach offers a graceful upgrade of a 155 Mb/s baseband system, and is compatible with baseband only optical network unit (ONU). We multiplexed a 155.52 Mb/s baseband signal with quadrature phase shift keying (QPSK) modulated passband digital video channels in the 270-1450 MHz range with minimal degradation. We used an additional 860 MHz carrier modulated with 8 Mb/s using QPSK as a passband test-signal. An optical-to-electrical (O/E) receiver using a PIN diode satisfies the need for class B operation as defined in ITU-T G983 (-28 dBm receiver sensitivity for a 10/sup -10/ bit error rate) with /spl sim/1.5 dBo/sup 1/ margin if we consider the proposed technique as an upgrade of the baseband 155 Mb/s to 622 Mb/s. Otherwise it only meets the specifications of class B (-30 dBm receiver sensitivity). However, an APD based receiver satisfies the power budget needs of ITU-T G983 class C operation (-33 dBm receiver sensitivity) with /spl sim/5.5 dBo margin for both baseband and passband with forward error correction (7/8 convolution and (96,110) Reed-Solomon coding). The available optical power margin with an APD receiver may be large enough that it can also allow use of 16-QAM in place of QPSK in class C mode or 64 QAM in class B mode.

Multimedia service interworking over heterogeneous networking environments

This article discusses technical issues related to delivery of multimedia services, such as video-on-demand, over heterogeneous networking environments. In particular, it describes the design and implementation of an experimental system for multimedia service interworking between a DAVIC (Digital Audio Visual Council) domain and an Internet domain. The system, called MIDDLEMEN (middlemen for multimedia environment), consists of the broker and the interworking unit, which work together to provide multimedia services across different types of networks in a seamless manner. The broker acts as a guide to multimedia services, and complements servers or clients that are not equipped with full functionality. The broker also controls the resources in MIDDLEMEN. The interworking unit performs various translation functions under the control of the broker, including stream transport protocol conversion, traffic monitoring and bit-rate control, service gateway conversion, and stream control conversion. Current implementation supports the delivery of a DAVIC-compliant VOD service from an ATM network to an IP network.

System Architecture for On-line Broadcast Archives

Consumer friendly delivery of multimedia digital services is drawing world attention. Broadcast archives are valuable multimedia resource centres, stocking audio and video materials of interest to a vast population across the globe. There is great potential of using these archival material for on-line access of information in respect of the material and also to some extent direct delivery of the material itself. The present paper describes the system architecture and implementation issues of an On-Line Broadcast Archives Management system (OL-BAMS) which entails all the functions of storage and dissemination taking advantage of emerging technology.

Modelling the delivery of multimedia services overHiperlan

Results from a detailed model of multimedia service delivery using the Hiperlan wireless LAN standard are reported. Hiperlan is shown to provide reasonable quality of service support for real-time services in several likely scenarios. However, the channel access prioritisation mechanism is shown to reduce to effectively two levels under conditions of network overload.

Managing QoS in Multimedia Services

We present a case study of multimedia service delivery in the World Wide Web environment. Our system is founded on the notion of end-to-end Quality-of-Service (QoS) management. We outline our view of an integrated management frame and explain how our QoS management architecture fits into this framework. We then describe our object-oriented multimedia delivery system based on CORBA and Java. We discuss some issues of stream delivery and management with reference to our own experiences.

An introduction to digital storage media-command and control

Digital storage media-command and control (DSM-CC) is a very recent ISO/IEC standard developed for the delivery of multimedia broadband services. Open protocols in this area are essential for the widespread deployment of such services. Total interoperability between service providers and consumers will require many different aspects of broadband service delivery to be addressed. This article gives an introductory overview of the different functions covered by the DSM-CC standard. Its purpose is to convey the scope of the DSM-CC standard and the basic reference model that underpinned the development of the standard.