Interactive Broadband Services Research Articles

Interference-Aware Radio Resource Management for Cognitive High-Throughput Satellite Systems.

By providing interactive broadband services to geographical areas underserved by terrestrial infrastructure, multi-beam satellite systems play a central role in future wireless communications. Targeting the terabit throughput requirements in satellite communications, we introduce a cognitive radio-based high-throughput satellite (HTS) system architecture where full frequency reuse is employed among beams. Moreover, by analyzing the characteristics of the considered architecture, we discuss the design challenges of radio resource management in cognitive HTS systems exposed to both intra-system and inter-system co-channel interference. Furthermore, to combat interference with low overhead, we propose a generic interference-aware resource management framework based on joint spatial division and multiplexing (JSDM). Under this framework, user grouping along with two-stage precoding is studied to achieve substantial improvement in the overall system throughput. Finally, some future research directions and challenges are also given.

Design of a 40/50 GHz satellite ground station for fade mitigation experiments

Due to the increasing demand in satellite capacity, driven by applications such as high-definition television (HDTV), 3D-TV and interactive broadband services, higher frequency bands will have to be exploited. The capacity on Ku-band is already becoming scarce and Ka-band systems are more commonly used. It can be expected that 40 and 50GHz (Q and V band) will have to be used in the future. At these frequencies the wave propagation effects have a significant impact on the performance. The traditional approach of implementing large fade margins in the system design is not suitable as it leads to expensive ground terminals. Fade mitigation by adaptive coding and modulation (ACM) is a cost-efficient method. To investigate the Q/V-band for future commercial exploitation, ESA's ALPHASAT satellite will provide experimental payloads for communications and wave propagation experiments. In Graz a Q/V-band ground station is currently under development. It will be equipped with a 3m tracking antenna, a 50W Klystron amplifier and a 290K LNA. Fade mitigation experiments will be conducted, initially using DVB-S2 modems which allow to vary the modulation scheme, the Forward Error Correction code and the symbol rate under control of the ACM computer. In addition, uplink power control can be combined with the ACM methods. A specially developed signal analyser provides precise measurement of the signal/noise ratio. In addition, propagation data will be available from a beacon receiver, also developed by Joanneum Research. Important goals of the experiment are to investigate the reliability of links under realistic operating conditions using ACM and to develop efficient ACM and signal/noise ratio measurement algorithms which can be later implemented in optimised modems for Q/V-band.The paper describes the ground station design and addresses the planned fade mitigation experiments.

Generic Optimization of Linear Precoding in Multibeam Satellite Systems

Multibeam satellite systems have been employed to provide interactive broadband services to geographical areas under-served by terrestrial infrastructure. In this context, this paper studies joint multiuser linear precoding design in the forward link of fixed multibeam satellite systems. We provide a generic optimization framework for linear precoding design to handle any objective functions of data rate with general linear and nonlinear power constraints. To achieve this, an iterative algorithm which optimizes the precoding vectors and power allocation alternatingly is proposed and most importantly, the proposed algorithm is proved to always converge. The proposed optimization algorithm is also applicable to nonlinear dirty paper coding. As a special case, a more efficient algorithm is devised to find the optimal solution to the problem of maximizing the proportional fairness among served users. In addition, the aforementioned problems and algorithms are extended to the case that each terminal has multiple co-polarization or dual-polarization antennas. Simulation results demonstrate substantial performance improvement of the proposed schemes over conventional multibeam satellite systems, zero-forcing and regularized zero-forcing precoding schemes in terms of meeting the traffic demand, e.g., using real beam patterns, over twice higher throughput can be achieved compared with the conventional scheme. The performance of the proposed linear precoding scheme is also shown to be very close to the dirty paper coding.

Servers for BT’s interactive TV services

Servers are a major component in an interactive TV service, and once systems of only modest size are considered, the technology requirements are challenging. If BT moves to a roll-out of broadband interactive TV services, then close working with chosen suppliers will be required if costs are to be viable.This paper looks at some server architectures and technologies that might eventually be part of BT’s interactive TV service.

Mobility management for m-commerce requests in wireless cellular networks

Increasing number of sophisticated services provided by the current wireless communication systems have caused a significant transition from E-commerce to M-commerce. Enterprises have provided considerable new opportunities to promote their businesses accessible from small mobile devices such as personal digital assistant (PDA) or mobiles phones. These facilities are envisioned as the most convenient way of using M-commerce. Using such services from mobile phones or PDAs equipped with GSM/GPRS involve effective mobility management mechanisms in cellular networks--a popular architecture for wireless networks. Success of such systems will largely depend on the reliable connection for the roaming users. Consequently, Quality of Service (QoS) provision is one of the most challenging issues in the heterogeneous wireless network-based m-commerce systems. Such m-commerce systems enable users to roam between different wireless networks operators and geographical areas while providing interactive broadband services and seamless connectivity. This paper presents an analytical framework to model scarce channels in any cell for maximizing channel utilization and efficient handling of handover requests. Typical numerical experiments are presented to validate the analytical solution against simulation to study the effect of bursty traffic upon the performance of the cell in any cellular networks.

Complementarities creating substitutes – possible paths towards 3G, WLAN/WiMAX and ad hoc networks

PurposeInternet and GSM have become the dominant designs for information and communication technology (ICT) industries in the late 1990s. Internet protocol (IP) is the dominant standard for cost effective networking and new interactive broadband services. GSM (2G) is currently the dominant cellular technology and it is the basis of GSM, GPRS (2.5G) and UMTS (3G), the GSM‐continuum of standards. The marriage of broadband internet and mobile has created open questions on which are the future winning wireless standards. Will mobile internet be based on the GSM‐continuum or on US wireless developments such as WLAN and WiMAX? In longer time‐scale the Mobile Ad‐hoc Network (MANET) which does not use any preinstalled communications infrastructure may also become a cost‐effective challenger to infrastructure based networks. The paper seeks to address these issues.Design/methodology/approachThe paper elaborates these questions with the aim to provide an analytically clarifying conceptualisation of the competitive relationships between 3G, WLAN/WiMAX and the emerging MANET opportunities both in network and application perspectives. By considering the interaction of the possible competitive regimes we analyze the disruptive capabilities of new solutions to become substitutes to the existing ones.FindingsThere are a number of open issues in the WLAN/WiMAX and MANET architectures, which require further work and global standardization. For the while, the integration of the personal applications to the GSM continuum seems to be the most potential approach to import internet to the mobile world. However, there is no winner yet, and the author strongly believes that a new wave of innovations may come around these lines and that these developments will also change the mobile technology and services landscape.Originality/valueThe paper contributes with a systemantic analysis of the competition between 3G, WLAN/WiMAX and ad hoc network technologies. A novelty in the analysis is that it incorporates both network access technologies and applications.

Performance evaluation of e-commerce requests in wireless cellular networks

Recent technological advances in mobile devices and wireless networks enable mobile users to order goods in an anywhere and anytime fashion. Quality of Service (QoS) provision is one of the most challenging issues in the heterogeneous wireless network-based e-commerce systems. Such e-commerce systems enable users to roam between different wireless networks operators and geographical areas while providing interactive broadband services and seamless connectivity. Due to movement of users during e-commerce requests, one of the most important QoS factors for successful completion of users' requests is related to handover of request from one cell to another. A handover could fail due to unavailability of sufficient bandwidth in the destination cell. Such failure of ongoing e-commerce requests is highly undesirable and can cause serious problems to the e-commerce users and the service providers. This paper proposes an enhanced priority queuing based handover scheme in order to ensure a seamless connectivity of e-commerce requests. It focuses on the performance anaylsis of the proposed scheme. Experimental study demonstrates that the proposed scheme provides QoS with low connection failure and mean response time for handover of e-commerce requests.

Competition and Regulatory Policies for Interactive Broadband Networks

Few phrases in public policy have become so overused so quickly as the information highway. Although it is unclear to many what that superhighway is or will be, this uncertainty has not prevented proposals to regulate the superhighway from being made. In this Article, we examine the economic principles that should govern competition and regulatory policies concerning the development and operation of the information superhighway. In Part II of this Article, we discuss the evolution of technology for interactive broadband networks. While Part II analyzes the production (or supply) side of interactive broadband networks, Part III examines the demand side and asks: What is the likely market for interactive broadband services? In Part IV, we explain the economic principles for open entry and efficient, subsidy-free pricing that are now widely accepted for regulating network industries. In Part V, we analyze regulatory policies intended to prevent incumbent, regulated firms (such as local exchange carriers) from cross-subsidizing their deployment and operation of interactive broadband services to the detriment of equally efficient rivals - and, eventually, consumers. In Part VI, we examine whether new interactive broadband services should be regulated. In Part VII, our discussion turns to the Canadian telecommunications market because of our familiarity with certain policies raised there recently in a major regulatory proceeding. In Part VIII, we examine whether the Canadian cable television industry should be protected from competition while it upgrades its network to provide interactive broadband services, including services that would compete with the voice and data services of local exchange carriers.

Using cable television networks for interactive home telemedicine services.

Most recent cable television network infrastructures can be used to deliver broadband interactive telemedicine services to the home. These facilities allow the provision of social and health services like medical televisiting for elderly, disabled and chronically ill patients; health tele-education; and teleconsultation on demand. Large numbers of patients could benefit from these services. There is also the increasing European tendency to offer customized home-care services. These applications are being developed and validated by a pilot project in Madrid as part of the ATTRACT project of the European Commission. The long-term aim is to develop broadband applications on a large scale to support low-cost interactive home telemedicine services for both patients and institutions.

Broadband interactive services and digital television at 42 GHz

This paper describes and evaluates the first results, from a trial under real conditions, of a wireless cellular interactive network at 42 GHz, for broadband services and digital (MPEG-2) television, realized in the frame of an European Union program, in the area of Athens. The adopted system architecture and network configuration are described and technical data concerning the development of the interactive services are provided. The performance of the system is also evaluated. Copyright © 1999 John Wiley & Sons, Ltd.

Broadband interactive services and digital television at 42 GHz

Broadband interactive services and digital television at 42 GHz

Elements of the emerging broadband information highway

General design considerations for the broadband information highway of the future are given in the context of interactive broadband services to the home. As potential precursors to this highway, the telephone, the Internet, and cable television networks are examined. Several emerging technologies are also examined as candidates for the future local subscriber loop. For the information highway, classes of network services are proposed that are independent of the specific network technologies used. It is suggested that the information highway be partitioned logically or physically so as to provide a variety of service levels according to the subscriber's cost and quality of service requirements. This should yield better network economies and provide the end user with a viable range of connectivity options.

A User Interface Design for a Video-on-demand Service Trial in an Educational Setting

SUMMARY Video-on-demand (VOD) is one of a series of emerging interactive broadband services. VOD provides users with the capability to access a vast variety of interactive programmes on demand, and give them full VCR-like control over their programme selections. This paper presents and describes a user interface that was designed for a business VOD service trial operated by Stentor, which began in January 1994, at two universities in Ottawa, Canada. It describes the service architecture and trial setting, as well as presents some trial results. Finally, some recommendations based on these results, and future enhancements to the VOD user interface, are described.

Interactive multimedia services to residential users

Despite the business risks involved in the introduction of digital video and interactive television, vigorous investments made by the telecommunication industries and content owners clearly demonstrate the belief that such services are going to happen. In this paper, a complete scenario for the provision of interactive multimedia services from the residential user's point of view is considered, focusing on software components. Initially, a reference architecture configuration, based on the DAVIC paradigm, suitable for the provision of residential interactive broadband services is presented. In addition to hardware capabilities, the system will be considered successful only if it is easy to learn, worth the time and cost-effective. Consequently, a set of possible service requirements is introduced and a development process for distributed interactive multimedia applications is proposed. Finally, based on experience gained from the implementation of applications in different residential trials throughout Europe, guidelines and methodologies for user interface design are illustrated.

TOBASCO: an innovative approach for upgrading CATV fiber-coax networks for broadband interactive services

To introduce broadband interactive services in a fiber-coax CATV network with high splitting ratio, a high-density wavelength multiplexing upgrading strategy in combination with conventional TDMA techniques is presented. It features flexible network reconfiguration via wavelength reassignment at the fiber terminating network units, a high interactive services capacity per user, and improved network scalability. On the fiber part of the network the interactive channels are carried in baseband, time-multiplexed (in ATM) in a number of wavelength channels. The article gives an overview of the most distinctive characteristics of TOBASCO. The system architecture as well as the evolutionary upgrade path are presented. The implications of the flexible wavelength allocation scheme on the network topology and, in particular, dynamic assignment strategies are analyzed. Finally, the field trial to be carried out in Gent is discussed.

Broadband Data Services over Residenial Access Networks

ese are truly exciting times for residential and business customers served by local telephone, cable television, and direct satellite providers. Perhaps for the first time, we are witnessing the application of computer networking techniques to telecommunication access network architectures. These local access options include fiber in the loop, fiber to the home, hybrid fibericoax, switched digital video, direct broadcast satellite, wireless microwave/RF links, broadband PCS, and so on. All these state-of-the-art access alternatives are being equipped with an overlaid TCP/IP data services delivery architecture to support high-speed interactive data services to the subscriber’s premises. Transmission rates from a few hundred kilobits per second to tens of megabits per second are envisioned using various digital subscriber line (xDSL over twisted pair) and RF subcarrier multiplexing (cable modems over coax) technologies. The ultimate objective is to equip the end user with high-speed access to the Internet, corporate intranets, and popular on-line services. This is with the grand intention of finally solving the last-mile bandwidth bottleneck and facilitating the deployment of advanced multimedia services such as work at home, distance learning, telemedicine, home shopping, electronic commerce, and high-speed Web access. This special issue is dedicated to provide up-to-date information on research topics, research results, and performance and economic comparisons of various access methods and architectures currently being considered for interactive broadband services (IBS) over residential access networks. The 1996 Telecommunications Deregulation Act allows both local and long-distance telephone service providers and television service providers to offer IBS to the home. Under this intense competition, the winning IBS providers would be those who can either use as much existing infrastructure as possible or cost-effectively and rapidly deploy access, transport, service, and management infrastructures. Research, investigations, standardization efforts, and field trials on all aspects of IBS to the home are progressing at full swing. We received more than 20 articles for publication in this special issue, but could accommodate only seven here. The reviewers selected the ones which fit

Managing the last mile [access network

No matter how good the transmission technology, if you can not manage it, you can not use it. Telecommunications planners are faced with simultaneously provisioning the explosion of lines linking homes and businesses with central offices and planning for a future where highly sophisticated interactive broadband services must be provided. Managing all portions of the network is complicated, but none more so than the access network known colloquially as "the last mile," the low data speed capacity lines that actually connect the home or business to the high-speed network. Before a line used for plain old telephone service (POTS), called a loop, can be used in higher speed applications it must be checked to make sure that it has the right electrical characteristics. The evolution of the loop from POTS to midband to broadband usage is examined emphasizing the relevant plant administration processes. Using today's special service administration is an expensive way to provide service. Alternates to special service provisioning are described.

Interactive broadband services and PCS network architecture

Interactive broadband services — including video, data, and the Internet — are currently emerging and in some cases, they are growing rapidly. In addition, wireless services, also experiencing rapid growth, are expanding even further with the introduction of personal communications services (PCS). Both wireline and wireless segments of telecommunications services are having a significant effect on public networks. This paper discusses the end-to-end network architecture needed to provide these services, as well as the design criteria associated with each one. Further, it details some residential broadband access realization alternatives now being considered.

Interactive broadband services and PCS network architecture

Interactive broadband services — including video, data, and the Internet — are currently emerging and in some cases, they are growing rapidly. In addition, wireless services, also experiencing rapid growth, are expanding even further with the introduction of personal communications services (PCS). Both wireline and wireless segments of telecommunications services are having a significant effect on public networks. This paper discusses the end-to-end network architecture needed to provide these services, as well as the design criteria associated with each one. Further, it details some residential broadband access realization alternatives now being considered.

Network management for residential broadband interactive data services

Although coaxial networks and hybrid fiber coaxial (HFC) networks have been in use for delivering television programs to the home, their usage as access networks to provide broadband interactive data services (BIDS) to the home is very recent. In this article, the authors highlight the importance of managing the networking infrastructure for BIDS and explore the unique requirements and challenges in managing HFC networks. Considering the operational requirements of BIDS operators, network maintenance, subscriber support, and planning are identified as the three functional areas that a BIDS network management system must address. It is argued that management support built into BIDS equipment (e.g., cable modems, headend cable termination units, subscriber PCs) can provide a cost-effective way of monitoring the status and performance of HFC networks, and some initial experiences of implementing and deploying network monitors in a real-world BIDS system are presented.