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Subscriber Line (subscriber + line)

Distribution by Scientific Domains

Information Science and Computing	50%

Kinds of Subscriber Line

digital subscriber line

Selected Abstracts

From voice-band modems to DSL technologies

INTERNATIONAL JOURNAL OF NETWORK MANAGEMENT, Issue 5 2001
Mark Peden
This paper provides an overview of the evolution of digital transmission in the copper access network from voice-band modems to Digital Subscriber Line (DSL) technologies. The various types of DSL technology are described. Copyright © 2001 John Wiley & Sons, Ltd. [source]

An optimal spectrum-balancing algorithm for digital subscriber lines based on particle swarm optimization

INTERNATIONAL JOURNAL OF COMMUNICATION SYSTEMS, Issue 9 2008
Meiqin Tang
Abstract This paper presents a new algorithm for optimal spectrum balancing in modern digital subscriber line (DSL) systems using particle swarm optimization (PSO). In DSL, crosstalk is one of the major performance bottlenecks, therefore various dynamic spectrum management algorithms have been proposed to reduce excess crosstalks among users by dynamically optimizing transmission power spectra. In fact, the objective function in the spectrum optimization problem is always nonconcave. PSO is a new evolution algorithm based on the movement and intelligence of swarms looking for the most fertile feeding location, which can solve discontinuous, nonconvex and nonlinear problems efficiently. The proposed algorithm optimizes the weighted rate sum. These weights allow the system operator to place differing qualities of service or importance levels on each user, which makes it possible for the system to avoid the selfish-optimum. We can show that the proposed algorithm converges to the global optimal solutions. Simulation results demonstrate that our algorithm can guarantee fast convergence within a few iterations and solve the nonconvex optimization problems efficiently. Copyright © 2008 John Wiley & Sons, Ltd. [source]

Protecting IPTV against packet loss: Techniques and trade-offs

BELL LABS TECHNICAL JOURNAL, Issue 1 2008
Natalie Degrande
Packet loss ratios that are harmless to the quality of data and Voice over Internet Protocol (VoIP) services may still seriously jeopardize that of Internet Protocol television (IPTV) services. In digital subscriber line (DSL)-based access networks, the last mile in particular suffers from packet loss, but other parts of the network may do so too. While on the last mile link, the packet loss is due to bit errors, in other parts of the network it is caused by buffers overflowing or the network experiencing (short) outages due to link or node failures. To retrieve lost packets, the application layer (AL) can use either a forward error correction (FEC) or a retransmission scheme. These schemes, when properly tuned, increase the quality of an IPTV service to an adequate level, at the expense of some overhead bit rate, extra latency, and possibly an increase in channel change time. This paper compares the performance of FEC schemes based on Reed-Solomon (RS) codes with that of retransmission schemes, all tuned to conform to the same maximum overhead bit rate allowed on the last mile link and on the feeder link, and their possible impact on the channel change time. We take into account two kinds of loss processes that can occur: isolated packet losses and burst packet losses. In almost all scenarios, retransmission outperforms FEC. © 2008 Alcatel-Lucent. [source]

Maintaining video quality and optimizing video delivery over the bandwidth constrained DSL last mile through intelligent packet drop

BELL LABS TECHNICAL JOURNAL, Issue 1 2008
Tom N. M. Van Caenegem
The technological challenges for an Internet Protocol television (IPTV) service provider to bring high quality video services into the home through a dedicated bandwidth limited digital subscriber line (DSL) access link are significant. However, at the same time, the dedicated DSL link provides certain opportunities as it allows for service customization on the network level, without impacting any other customers. In this paper, the concept of intelligent packet drop inside a digital subscriber line access multiplexer (DSLAM) is introduced. Intelligent packet drop makes use of the fact that some packets containing video information (e.g., I-picture or P-picture) are more important than others (e.g., B-picture), and this importance level can be indicated in the packet header. When congestion in the DSLAM occurs, the low priority packets are preferentially dropped. Provided some (simple) picture loss concealment is performed in the set-top box, intelligent packet drop will not significantly impact the quality of experience (QoE), as evidenced by subjective tests that have been conducted. Simulations have shown that the intelligent packet drop in a DSLAM enables the IPTV service provider to increase the number of customers eligible for a given IPTV service package delivered over the DSL link. It also enables fast channel change (FCC) service without dedicated bandwidth overhead. © 2008 Alcatel-Lucent. [source]

Ethernet aggregation and core network models for effcient and reliable IPTV services

BELL LABS TECHNICAL JOURNAL, Issue 1 2007
Christian Hermsmeyer
With the growing interest on wireline network architectures for residential triple-play and business Ethernet services there is a renewed demand for efficient and reliable packet-based transport capabilities between the content providers and the end users. Voice and data traffic carried over a variety of access technologies is collected via technology-specific access networks (e.g., digital subscriber line [xDSL], passive optical network [xPON], and wireless fidelity [WiFi]). Metro and core networks need to aggregate the various user flows from different access network nodes and provide scalable and cost-effective distribution of various flow types (e.g., Internet access, voice, video on demand, and broadcast TV services) to the relevant service access points. Varying quality of service and resiliency requirements for these services are being reflected in a new breed of converged Ethernet and optical network elements with capabilities to interwork the bearer-planes of these two networking technologies seamlessly. Network elements based on Ethernet/Optical converged technology are able to select the most fitting mechanisms from each networking technology to meet the transport requirements for each individual service demand better while providing significantly enhanced implementation and operational efficiencies. This paper discusses network architecture models and network elements addressing these goals. © 2007 Alcatel-Lucent. [source]

Waiting for Broadband: Local Competition and the Spatial Distribution of Advanced Telecommunication Services in the United States

GROWTH AND CHANGE, Issue 2 2004
TONY H. GRUBESIC
ABSTRACT With the passage of the Telecommunications Act of 1996, Congress directed the Federal Communications Commission and all fifty U.S. states to encourage the deployment of advanced telecommunication capability in a reasonable and timely manner. Today, with the rollout of advanced data services such as digital subscriber lines (xDSL), cable modems, and fixed wireless technologies, broadband has become an important component of telecommunication service and competition. Unfortunately, the deployment of last-mile infrastructure enabling high-speed access has proceeded more slowly than anticipated and competition in many areas is relatively sparse. More importantly, there are significant differences in the availability of broadband services between urban and rural areas. This paper explores aspects of broadband access as a function of market demand and provider competition. Data collected from the Federal Communications Commission is analyzed using a geographic information system and spatial statistical techniques. Results suggest significant spatial variation in broadband Internet access as a function of provider competition in the United States. [source]

An optimal spectrum-balancing algorithm for digital subscriber lines based on particle swarm optimization

Efficient packet classification on network processors

INTERNATIONAL JOURNAL OF COMMUNICATION SYSTEMS, Issue 1 2008
Koert Vlaeminck
Abstract Always-on networking and a growing interest in multimedia- and conversational-IP services offer an opportunity to network providers to participate in the service layer, if they increase functional intelligence in their networks. An important prerequisite to providing advanced services in IP access networks is the availability of a high-speed packet classification module in the network nodes, necessary for supporting any IP service imaginable. Often, access nodes are installed in remote offices, where they terminate a large number of subscriber lines. As such, technology adding processing power in this environment should be energy-efficient, whilst maintaining the flexibility to cope with changing service requirements. Network processor units (NPUs) are designed to overcome these operational restrictions, and in this context this paper investigates their suitability for wireline and robust packet classification in a firewalling application. State-of-the-art packet classification algorithms are examined, whereafter the performance and memory requirements are compared for a Binary Decision Diagram (BDD) and sequential search approach. Several space optimizations for implementing BDD classifiers on NPU hardware are discussed and it is shown that the optimized BDD classifier is able to operate at gigabit wirespeed, independent of the ruleset size, which is a major advantage over a sequential search classifier. Copyright © 2007 John Wiley & Sons, Ltd. [source]