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Access Technology (access + technology)

Distribution by Scientific Domains

Engineering	57%

Selected Abstracts

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]

Mobile-initiated network-executed SIP-based handover in IMS over heterogeneous accesses

INTERNATIONAL JOURNAL OF COMMUNICATION SYSTEMS, Issue 9-10 2010
Wei-Kuo Chiang
Abstract The services of next generation networks are envisioned to be potentially capable of seamless mobility in spite of the heterogeneity in underlying access technologies. It is undoubted that to accomplish seamless services across heterogeneous networking environments gets harder in case of simultaneous mobility. In this article, we propose a mobile-initiated network-executed (MINE) session initial protocol (SIP)-based handover mechanism to facilitate simultaneous mobility in IP multimedia subsystem over heterogeneous accesses. The novelty of the proposed approach is that no changes are required to the existing network infrastructure since handover decision is fully made by the mobile host (MH) and handover execution is performed by a new-added application server called mobility server (MS). When the MH decides to initiate a handover and obtains a new IP address, it will send a SIP Publish message to trigger the MS to carry out the handover execution. With the network-executed design of the MINE, the MS can perform third-party registration for security re-association and third-party call control for session re-establishment in parallel. Moreover, the Master,Slave Determination procedures derived from H.245 are used in the MS to handle fairly the racing conditions resulting from simultaneous mobility such that redundant message flows are eliminated. Mathematical analyses present that the MINE can shorten the handover latency and reduce power consumption, as observed from a comparison with the integrated solution of an optimized macro-mobility mechanism and a receiver-side simultaneous mobility approach. Copyright © 2010 John Wiley & Sons, Ltd. [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]

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

Hopfield neural-network-based dynamic resource allocation scheme for non-real-time traffic in wireless networks

INTERNATIONAL JOURNAL OF COMMUNICATION SYSTEMS, Issue 2 2009
José F. Monserrat
Abstract Dynamic resource allocation (DRA) plays a fundamental role in current and future wireless networks, including 3G systems. In this paper, a scheduling DRA scheme for non-real-time (NRT) packet services in wireless system is proposed based on the use of Hopfield neural networks (HNN). The scheme exploits the fast response time of HNN for solving NP optimization problems and has been particularized for the downlink transmission in a UMTS system, although it could be easily extended to any other radio access technology. The new DRA scheme follows a delay-centric approach, since it maximizes the overall system resource utilization while minimizing the packet delay. Simulation results confirm that the proposed HNN-based DRA scheme is effective in supporting different types of NRT services, while achieving efficient utilization of radio resources. Copyright © 2008 John Wiley & Sons, Ltd. [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]