Access Networks (access + network)

Distribution by Scientific Domains


Selected Abstracts


Robust tower location for code division multiple access networks

NAVAL RESEARCH LOGISTICS: AN INTERNATIONAL JOURNAL, Issue 2 2007
Jay M. Rosenberger
Abstract Designing Code Division Multiple Access networks includes determining optimal locations of radio towers and assigning customer markets to the towers. In this paper, we describe a deterministic model for tower location and a stochastic model to optimize revenue given a set of constructed towers. We integrate these models in a stochastic integer programming problem with simple recourse that optimizes the location of towers under demand uncertainty. We develop algorithms using Benders' reformulation, and we provide computational results. © 2006 Wiley Periodicals, Inc. Naval Research Logistics, 2007 [source]


Access network discovery and selection in the evolved 3GPP multi-access system architecture

EUROPEAN TRANSACTIONS ON TELECOMMUNICATIONS, Issue 6 2010
Joachim Sachs
The system architecture evolution (SAE) of mobile networks specified in 3GPP release 8 comprises an evolved packet core (EPC) network to which different types of access networks can be connected. Inter-system mobility management enables users to change the access network while maintaining ongoing data sessions. One important functionality in a 3GPP system is how a mobile terminal discovers and selects available access networks. In this paper we describe the access network discovery and selection functionality used in 3GPP release 8; we explain the differences of the methods applied for 3GPP access networks (GERAN, UTRAN, E-UTRAN), for fixed or wireless non-3GPP access networks (e.g. WLAN, WiMAX), as well as the optimisation used for CDMA2000 access networks. Copyright © 2010 John Wiley & Sons, Ltd. [source]


Assessment of the access selection gain in multi-radio access networks

EUROPEAN TRANSACTIONS ON TELECOMMUNICATIONS, Issue 3 2009
Joachim Sachs
In this paper, we investigate the capacity gain of access selection in a multi-radio access network with heterogeneous radio access technologies (RATs). We classify the kinds of gain that can be achieved by access selection: statistical multiplexing in the multi-access system leads to a trunking gain, spatial transmission diversity results from the geographic capacity distribution of the cell layout, stochastic transmission diversity exploits the multi-path fading characteristics. We show how these different properties are affected by the cell layout of the different RATs, the characteristics of each RAT and the traffic load distribution in the network. In a simulation environment the system capacity for the combination of two wide-area access technologies, as well as, for the combination of a wide-area and a local-area access technology is investigated. For this, we compare two different access selection algorithms. One uses the radio link quality as an input parameter, while the other also considers the cell load. We derive quantitative figures for the capacity gain in a large number of scenarios and show that load-based access selection can significantly increase the capacity. We show that the gain of an overlay of local-area access cells provides little capacity gain for uniform geographic load distribution, whereas significant gain can be achieved when most users are located at hotspots. Copyright © 2007 John Wiley & Sons, Ltd. [source]


Adaptive measurement-based traffic engineering in small differentiated services domains

EUROPEAN TRANSACTIONS ON TELECOMMUNICATIONS, Issue 1 2007
Sven Krasser
In this paper, we propose a framework for measurement-based traffic engineering and connection admission control in small-differentiated services domains. The domain investigated is a wired radio access network based on the Internet protocol (IP). This framework is evaluated by simulation using the popular network simulator ns-2. The framework is adaptive to changes in the network load and supports multiple types of service. All traffic-engineering decisions are made by edge routers (ERs) at the rim of the network domain. Multiple disjoint paths are configured between those ERs. Network state information is gathered in two different fashions. We evaluate a scheme based on the states of the queues on each alternative path and a scheme based on end-to-end probe packet transmission characteristics on each alternative path. Both schemes are compared to a shortest path first (SPF) routing approach. Copyright © 2006 AEIT [source]


A study on a receiver-based management scheme of access link resources for QoS-controllable TCP connections

INTERNATIONAL JOURNAL OF COMMUNICATION SYSTEMS, Issue 7 2006
Kazuhiro Azuma
Abstract Although the bandwidth of access networks is rapidly increasing with the latest techniques such as DSL and FTTH, the access link bandwidth remains a bottleneck, especially when users activate multiple network applications simultaneously. Furthermore, since the throughput of a standard TCP connection is dependent on various network parameters, including round-trip time and packet loss ratio, the access link bandwidth is not shared among the network applications according to the user's demands. In this thesis, we present a new management scheme of access link resources for effective utilization of the access link bandwidth and control of the TCP connection's throughput. Our proposed scheme adjusts the total amount of the receive socket buffer assigned to TCP connections to avoid congestion at the access network, and assigns it to each TCP connection according to characteristics in consideration of QoS. The control objectives of our scheme are (1) to protect short-lived TCP connections from the bandwidth occupation by long-lived TCP connections, and (2) to differentiate the throughput of the long-lived TCP connections according to the upper-layer application's demands. One of the results obtained from the simulation experiments is that our proposed scheme can reduce the delay of short-lived document transfer perceived by the receiver host by up to about 90%, while a high utilization of access link bandwidth is maintained. Copyright © 2006 John Wiley & Sons, Ltd. [source]


Urban mesh and ad hoc mesh networks

INTERNATIONAL JOURNAL OF NETWORK MANAGEMENT, Issue 2 2008
Anders Nilsson Plymoth
Mesh networking is currently gaining much attention, within both academia and industry. Mesh networking allows cheap and fast deployment of wireless services. It is regarded as a very promising solution for urban deployment scenarios as well as for temporary emergency response situations. Another related promising field is that of ad hoc wireless networking, which consists of mobile nodes that dynamically create and maintain a network without the need for any infrastructure. We propose a solution and architecture for urban mesh ad hoc networks, a network that combines mesh networking with ad hoc networks for urban environments. We present four types of ad hoc mesh and ad hoc mesh networks. The most general one consists of mesh nodes, called mesh points (MP), that act as a type of access point for user nodes (UN). The MPs have at least two interfaces: one which is used to communicate with UNs, and one which is used to maintain the mesh access network and transport data. These two interfaces can basically use any type of technology (IEEE 802.11 a/b/g, WiMax, etc.), and for capacity reasons it is generally regarded that the best solution is to let the mesh interface operate on a separate high-capacity channel or channels. An intricate part of these types of networks are routing and location services. In our solution, UN devices operate in ad hoc mode running an ad hoc routing protocol. This allows UNs that wish to communicate to connect directly in an ad hoc manner, or through an MP. An important question is therefore whether two UNs that wish to communicate should connect through the mesh or connect directly. We show that from a capacity point of view whether a UN should route its packets to the closest available MP, or through a ad hoc network, depends on the environment the network is located, the amount traffic and the type of protocols used. Since MPs need to know where to route packets within the mesh, i.e., locating the MP closest to the destination UN, each UN run a small application that registers the UN to the mesh network. In addition to the above features we have developed a new MAC that quickly queries two candidate nodes, which picks the candidate with the currently best radio conditions. This enable nodes to cope with deep dips in signal strength due to fast fading, a well-known problem in urban environments. We show that this new protocol achieves significantly lower delays. We also show that in dense urban environments performance and battery lifetime can be improved if ad hoc technologies are used. Copyright © 2007 John Wiley & Sons, Ltd. [source]


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]


Visible light wireless transmission based on optical access network using white light-emitting diode and electroabsorption transceiver

MICROWAVE AND OPTICAL TECHNOLOGY LETTERS, Issue 4 2010
Yong-Hwan Son
Abstract We propose the visible light communication (VLC) system based on optical access network using light-emitting diode (LED) and electroabsorption transceiver (EAT). The EAT based on electroabsorption modulator is used as an optical network unit in order to be connected with VLC link based on white LED and photodiode (PD). The proposed architecture is demonstrated experimentally, and its performance is verified through the experimental investigation of quality factor and eye pattern of 5 Mbps baseband data. The variation of performance is shown depending on both the existence of the ambient light and the distance between the LED array and PD. A total of 5 Mbps downlink and uplink transmission is verified through 23.2-km single-mode fiber and wireless channel experimentally. © 2010 Wiley Periodicals, Inc. Microwave Opt Technol Lett 52:790,793, 2010; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.25045 [source]


Energy scavenging for energy efficiency in networks and applications

BELL LABS TECHNICAL JOURNAL, Issue 2 2010
Kyoung Joon Kim
Telecommunication networks will play a huge part in enabling eco-sustainability of human activity; one of the first steps towards this is to dramatically increase network energy efficiency. In this paper we present two novel approaches for energy scavenging in networks. One involves thermal energy scavenging for improving wireless base station energy efficiency, and the other involves mechanical energy scavenging for powering sensors in sensor networks, for machine-to-machine (M2M) communications, and for smart grid applications. Power amplifier (PA) transistors in base stations waste 30 percent of the total energy used in a wireless access network (WAN) as heat to the environment. We propose a thermoelectric energy recovery module (TERM) to recover electricity from the waste heat of PA transistors. A fully coupled thermoelectric (TE) model, combining thermoelectricity and heat transfer physics, is developed to explore the power generation performance and efficiency as well as the thermal performance of the TERM. The TE model is comprehensively used to determine optimized pellet geometries for power generation and efficiency as a function of PA transistor heat dissipation, heat sink performance, and load resistance. Maximum power generation and efficiency for various parametric conditions are also explored. Untapped kinetic energy is almost everywhere in the form of vibrations. This energy can be converted into electrical energy by means of transducers to power wireless sensors and mobile electronics in the range of microwatts to a few milliwatts. However, many problems limit the efficiency of current harvesting generators: narrow bandwidth, low power density, micro-electro-mechanical system (MEMS) scaling, and inconsistency of vibrating sources. We explore energy scavenger designs based on multiple-mass systems to increase harvesting efficiency. A theoretical and experimental study of two degrees-of-freedom (2-DOF) vibration-powered generators is presented. Both electromagnetic and piezoelectric conversion methods are modeled by using a general approach. Experimental results for the multi-resonant system are in agreement with the analytical predictions and demonstrate significantly better performance in terms of maximum power density per total mass and a wider bandwidth compared to single DOF (1-DOF) generators. © 2010 Alcatel-Lucent. [source]


Performance assessment of next-generation wireless mobile systems

BELL LABS TECHNICAL JOURNAL, Issue 4 2009
Krishna Balachandran
The deployment of third generation (3G) systems such as Universal Mobile Telecommunications System (UMTS) and code division multiple access (CDMA) 1X is now ubiquitous. Furthermore, several operators have already deployed evolved 3G systems such as high speed packet access (HSPA) and 1◊ evolution data optimized (1◊ EV-DO). These 3G and evolved 3G systems are based on spread spectrum technologies. Now the industry has begun to focus on next-generation wireless systems based on orthogonal frequency division multiplexing (OFDM) technology, flat-Internet Protocol (IP) architectures, and advanced multiple input-multiple output (MIMO) capabilities. These next-generation technologies, primarily are: 3rd Generation Partnership Project (3GPP)-based evolved UMTS terrestrial radio access network (EUTRAN), also called Long Term Evolution (LTE); 3rd Generation Partnership Project 2 (3GPP2)-based Ultra Mobile Broadband (UMB); and Institute of Electrical and Electronics Engineers (IEEE) 802. 16e-based Worldwide Interoperability for Microwave Access (WiMAX). These technologies are in the final specifications to initial deployment phases in selected markets. This paper provides an overview and performance analysis of these next-generation technologies based on their initial releases. Additionally, a comparative performance analysis of these technologies is also presented. © 2009 Alcatel-Lucent. [source]


IP-driven access-independent resource management in converged access networks

BELL LABS TECHNICAL JOURNAL, Issue 2 2007
Markus Bauer
A key requirement on future networks is to provide the user with seamless broadband access for triple-play services via any available access technology with high end-to-end quality of service. In this paper we propose a novel resource management concept on the network layer that utilizes service- and user-specific cross-layer metrics to control the resources in an all-Internet Protocol (IP) access network optimally via IP mechanisms such as routing and traffic engineering. We interpret any link, wireless or wireline, as an IP-hop in an all-IP network where major lower layer information is included in such metrics. This approach turns out to be access technology,independent, leading to a unified resource management concept in a "converged" wireline/wireless environment. With this proposal, we leverage flat IP-based cellular architectures like the Alcatel-Lucent Base Station Router (BSR) technologies and show how wireless and wireline access nodes can be integrated into future converged all-IP networks. The paper is based on results from ScaleNet, a European research initiative that is dedicated to advancing a vision of a scalable and flexible next-generation access network that provides an IP-optimized integration of heterogeneous access systems for future broadband multimedia services. © 2007 Alcatel-Lucent. [source]


Access network discovery and selection in the evolved 3GPP multi-access system architecture

EUROPEAN TRANSACTIONS ON TELECOMMUNICATIONS, Issue 6 2010
Joachim Sachs
The system architecture evolution (SAE) of mobile networks specified in 3GPP release 8 comprises an evolved packet core (EPC) network to which different types of access networks can be connected. Inter-system mobility management enables users to change the access network while maintaining ongoing data sessions. One important functionality in a 3GPP system is how a mobile terminal discovers and selects available access networks. In this paper we describe the access network discovery and selection functionality used in 3GPP release 8; we explain the differences of the methods applied for 3GPP access networks (GERAN, UTRAN, E-UTRAN), for fixed or wireless non-3GPP access networks (e.g. WLAN, WiMAX), as well as the optimisation used for CDMA2000 access networks. Copyright © 2010 John Wiley & Sons, Ltd. [source]


Assessment of the access selection gain in multi-radio access networks

EUROPEAN TRANSACTIONS ON TELECOMMUNICATIONS, Issue 3 2009
Joachim Sachs
In this paper, we investigate the capacity gain of access selection in a multi-radio access network with heterogeneous radio access technologies (RATs). We classify the kinds of gain that can be achieved by access selection: statistical multiplexing in the multi-access system leads to a trunking gain, spatial transmission diversity results from the geographic capacity distribution of the cell layout, stochastic transmission diversity exploits the multi-path fading characteristics. We show how these different properties are affected by the cell layout of the different RATs, the characteristics of each RAT and the traffic load distribution in the network. In a simulation environment the system capacity for the combination of two wide-area access technologies, as well as, for the combination of a wide-area and a local-area access technology is investigated. For this, we compare two different access selection algorithms. One uses the radio link quality as an input parameter, while the other also considers the cell load. We derive quantitative figures for the capacity gain in a large number of scenarios and show that load-based access selection can significantly increase the capacity. We show that the gain of an overlay of local-area access cells provides little capacity gain for uniform geographic load distribution, whereas significant gain can be achieved when most users are located at hotspots. Copyright © 2007 John Wiley & Sons, Ltd. [source]


2-Dimensional code design for an optical CDMA system with a parallel interference cancellation receiver

EUROPEAN TRANSACTIONS ON TELECOMMUNICATIONS, Issue 7 2007
MikaŽl Morelle
The objective of this paper is to design a two-Dimensional Optical Code Division Multiple Access system (2D-OCDMA) for application in access networks, with coding and decoding functions performed by electronic devices. We present a new construction method of Multi-Wavelength Optical Orthogonal Codes (MWOOC), which permits a high flexibility in the code parameters choice. This work evaluates in the noiseless case, the MWOOC potentialities for two receiver structures: a Conventional Correlation Receiver (CCR) and a Parallel Interference Cancellation receiver (PIC). We show that with a PIC receiver, it is possible to design two-Dimensional codes that respect the access specifications. Copyright © 2007 John Wiley & Sons, Ltd. [source]


A utility-based capacity optimization framework for achieving cooperative diversity in the hierarchical converged heterogeneous wireless networks

INTERNATIONAL JOURNAL OF COMMUNICATION SYSTEMS, Issue 12 2008
Mugen Peng
Abstract A hierarchical convergence mechanism for the heterogeneous wireless communication system via the heterogeneous cooperative relay node is presented in this paper, in which the techniques of cooperative communication and wireless relay are utilized to improve performances of the individual user and the overall converged networks. In order to evaluate the benefits of the proposal, a utility-based capacity optimization framework for achieving the heterogeneous cooperative diversity gain is proposed. The heterogeneous cooperative capacity, relay selection and power allocation theoretical models are derived individually. The joint optimization model for relay selection and power allocation is presented as well. Owing to the computation complexity, the sub-optimal cooperative relay selection algorithm, the sub-optimal power allocation algorithm and the sub-optimal joint algorithm are determined to approach the maximum overall networks' spectrum efficiency. These proposed algorithms are designed in conformance to guarantee the equivalent transmission rates of the different wireless access networks. The simulation results demonstrate that the utility-based capacity model is available for the heterogeneous cooperative wireless communication system, and the proposed algorithms can improve performances by achieving the cooperative gain and taking full advantage of the cross-layer design. Copyright © 2008 John Wiley & Sons, Ltd. [source]


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]


A study on a receiver-based management scheme of access link resources for QoS-controllable TCP connections

INTERNATIONAL JOURNAL OF COMMUNICATION SYSTEMS, Issue 7 2006
Kazuhiro Azuma
Abstract Although the bandwidth of access networks is rapidly increasing with the latest techniques such as DSL and FTTH, the access link bandwidth remains a bottleneck, especially when users activate multiple network applications simultaneously. Furthermore, since the throughput of a standard TCP connection is dependent on various network parameters, including round-trip time and packet loss ratio, the access link bandwidth is not shared among the network applications according to the user's demands. In this thesis, we present a new management scheme of access link resources for effective utilization of the access link bandwidth and control of the TCP connection's throughput. Our proposed scheme adjusts the total amount of the receive socket buffer assigned to TCP connections to avoid congestion at the access network, and assigns it to each TCP connection according to characteristics in consideration of QoS. The control objectives of our scheme are (1) to protect short-lived TCP connections from the bandwidth occupation by long-lived TCP connections, and (2) to differentiate the throughput of the long-lived TCP connections according to the upper-layer application's demands. One of the results obtained from the simulation experiments is that our proposed scheme can reduce the delay of short-lived document transfer perceived by the receiver host by up to about 90%, while a high utilization of access link bandwidth is maintained. Copyright © 2006 John Wiley & Sons, Ltd. [source]


Broadband consumer electronics networking and automation

INTERNATIONAL JOURNAL OF COMMUNICATION SYSTEMS, Issue 1 2004
Th. Zahariadis
Abstract Although a critical mass of households worldwide have access to the information superhighway, the broadband consumer networking and automation market is still evolving very slowly. Two reasons may be identified for this delay. The first one is related to the lack of broadband home data networks. Consumer electronics networks either do not exist at all or they are not able to support multimedia communications. The second reason is the large variety of ad hoc consortia or (un-)authorized standardization bodies that have been defining independent, in many cases non-interoperable specifications for residential networks. In this paper, we analyse and compare some of the most widely accepted, foreseen or advanced current and future broadband consumer electronics networking technologies able to support home automation and multimedia in-home appliances. Technologies and standards are categorized in three groups based on their physical medium requirements. Moreover, we discuss technologies that are independent of the lower layers, and aim to provide convergence between multiple in-home and access networks. Copyright © 2004 John Wiley & Sons, Ltd. [source]


Using a multiple priority reservation MAC to support differentiated services over HFC systems,

INTERNATIONAL JOURNAL OF COMMUNICATION SYSTEMS, Issue 4 2002
J. D. Angelopoulos
Abstract The successful commercial deployment of Hybrid Fibre/Coaxial (HFC) access networks in the residential market has so far been driven by demand for faster Internet access and the prospects of a host of new services based on real-time voice and video. To sustain their growth rates and compete with alternative approaches, such as ADSL, they must be enhanced with the capability to efficiently handle quality-intensive real-time services. The new multi-service paradigm mandates isolation of traffic classes, conditioning of entering traffic and preventive control in addition to traditional closed-loop control. The differentiated services (DiffServ) architecture with its relevant traffic control tools and the bundling of behaviour aggregates is particularly suited to the H/W-based MAC of HFC systems. It constitutes a suitable framework enabling the support of proliferating real-time voice- and video-based services while aligning the system to the emerging Internet strategy of scalable service differentiation. The implementation of such a solution in the ACTS 327AROMA research project is presented in this paper. The performance of the system is evaluated using computer simulation. Copyright © 2002 John Wiley & Sons, Ltd. [source]


A distributed networking system for multimedia Internet access service using ATM over ADSL

INTERNATIONAL JOURNAL OF NETWORK MANAGEMENT, Issue 6 2004
Daniel Won-Kyu Hong
This paper proposes a distributed networking system architecture for Internet-access service provision using ATM over xDSL technology. We describe the hierarchical network model in deploying ADSL services across the ATM access networks, which can easily accommodate the explosive growth of ADSL subscribers in the future. In addition, this paper describes the distributed networking system and its capability to provide a systemic network management using the principal networking concepts of service ordering, addressing, routing, adaptation and switching. All of the networking system components with CORBA objects in favor of the distribution and location transparency are defined and described using the CORBA interface description language (IDL) for commonality. Lastly, we present its implementation and operation in Korea Telecom.,Copyright © 2004 John Wiley & Sons, Ltd. [source]


Robust tower location for code division multiple access networks

NAVAL RESEARCH LOGISTICS: AN INTERNATIONAL JOURNAL, Issue 2 2007
Jay M. Rosenberger
Abstract Designing Code Division Multiple Access networks includes determining optimal locations of radio towers and assigning customer markets to the towers. In this paper, we describe a deterministic model for tower location and a stochastic model to optimize revenue given a set of constructed towers. We integrate these models in a stochastic integer programming problem with simple recourse that optimizes the location of towers under demand uncertainty. We develop algorithms using Benders' reformulation, and we provide computational results. © 2006 Wiley Periodicals, Inc. Naval Research Logistics, 2007 [source]


Packet OADMs for the next generation of ring networks

BELL LABS TECHNICAL JOURNAL, Issue 4 2010
Dominique Chiaroni
The deployment of fiber-to-the-home (FTTH) technology in access networks is creating new demands on metropolitan area and backbone networks. The increasing bit rate per user and the simplification of access networks will make the traffic profile more bursty, requiring new flexible techniques at the metropolitan area network. This paper describes a ring network exploiting optical transparency and packet granularity. After a description of the packet optical add/drop multiplexer (POADM)-based network model motivated by specifications derived from expected needs, the paper addresses the advantages of the approach and the feasibility of the concept. © 2010 Alcatel-Lucent. [source]


Converged service continuity: A challenge for the merchant and the architect

BELL LABS TECHNICAL JOURNAL, Issue 2 2008
Linas Maknavicius
Offering service continuity is about providing customers with ubiquitous, uninterrupted, and transparent access to personalized content and services, both when they move between various access networks and when it is desirable to continue a session on another terminal at any time. The novelty does not only lie in new functional implementation, but in new business and distribution models as well. To make this vision a reality, the merchant and the architect must work jointly. Service continuity thus strives to eliminate barriers created by access conditions and user terminals, in response to generalization of the user-centric paradigm. The variety of existing technical environments, however, involves constraints that raise new operational challenges for the realization of communication and media service continuity. Moreover, bringing service continuity to the market depends on forward-looking business models based on interplay among actors in the market. © 2008 Alcatel-Lucent. [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]


Advanced IMS client supporting secure signaling

BELL LABS TECHNICAL JOURNAL, Issue 4 2008
Ramana Isukapalli
With recent advances in core and access networks and the availability of increased bandwidth and sophisticated devices for end users, there is an increased demand for client applications running on mobile devices, such as laptops and handheld devices, to support real time applications like Voice over Internet Protocol (VoIP) and streaming video, apart from traditional applications like web browsing. This paper presents a prototype IP Multimedia Subsystem (IMS) client, which serves as a VoIP client to set up calls between Internet Protocol (IP) devices and interworks with circuit-switched networks to deliver calls to public switched telephone network (PSTN) phones. It implements supplementary services (including call waiting, call transfer, and call forwarding); supports multimedia ringing, short message service/multimedia messaging service (SMS/MMS), audio/video conferencing, and peer-to-peer video; and it can deliver a call to a user (as opposed to a device) by simultaneously ringing multiple devices registered by the user. Further, to address various security concerns, the client supports Hypertext Transfer Protocol (HTTP) digest authentication using Message Digest 5 (MD5) cryptographic function authentication and key agreement (AKA) and can create secure tunnels to the core network using IP security (IPsec). © 2008 Alcatel-Lucent. [source]


IP-driven access-independent resource management in converged access networks

BELL LABS TECHNICAL JOURNAL, Issue 2 2007
Markus Bauer
A key requirement on future networks is to provide the user with seamless broadband access for triple-play services via any available access technology with high end-to-end quality of service. In this paper we propose a novel resource management concept on the network layer that utilizes service- and user-specific cross-layer metrics to control the resources in an all-Internet Protocol (IP) access network optimally via IP mechanisms such as routing and traffic engineering. We interpret any link, wireless or wireline, as an IP-hop in an all-IP network where major lower layer information is included in such metrics. This approach turns out to be access technology,independent, leading to a unified resource management concept in a "converged" wireline/wireless environment. With this proposal, we leverage flat IP-based cellular architectures like the Alcatel-Lucent Base Station Router (BSR) technologies and show how wireless and wireline access nodes can be integrated into future converged all-IP networks. The paper is based on results from ScaleNet, a European research initiative that is dedicated to advancing a vision of a scalable and flexible next-generation access network that provides an IP-optimized integration of heterogeneous access systems for future broadband multimedia services. © 2007 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]