Home About us Contact
|
Home About us Contact | ||
|
|
||
Time Division Multiplexing (time + division_multiplexing)
Selected AbstractsAnalysis of a clock-recovery technique for circuit emulation services over packet networksINTERNATIONAL JOURNAL OF COMMUNICATION SYSTEMS, Issue 1 2008James Aweya Abstract One important requirement of circuit emulation services (CES) over packet networks is clock synchronization and timing distribution among the nodes. CES depends on reliable and high-quality timing for operations. In the time division multiplexing (TDM) world, whether plesiochronous digital hierarchy (PDH), synchronous digital hierarchy (SDH) or synchronous optical network (SONET) based, timing and synchronization is inherent in the design of the network. However, when timing critical services such PDH and SDH/SONET are carried over packet network (e.g. IP, Ethernet, etc.), the timing element is lost and has to be carried across the packet network by other means. A well-known and widely implemented technique for clock recovery in CES is one that is based on packet inter-arrival time (sometimes called time difference of arrival) averaging. The technique is very simple to implement but provides good performance only when packet losses and packet delay variation (PDV) are very low and well controlled. This technique has been extensively analysed through simulations but has not been fully characterized analytically with correlated traffic in the literature. In this paper, we provide a full analytical examination of this well-known clock recovery technique. We analyse the effects of correlation of the delay variation in the traffic stream on the quality of the clock recovered by a receiver. We prove analytically that, for a general input process, high correlation of the delay variation produces a large variance of the recovered clock. Copyright © 2007 John Wiley & Sons, Ltd. [source] Development of mobile broadband interactive satellite access system for Ku/Ka bandINTERNATIONAL JOURNAL OF SATELLITE COMMUNICATIONS AND NETWORKING, Issue 2 2006Yun-Jeong Song Abstract It is difficult to implement the broadband satellite Internet and broadcasting service for mobile environment. The paper presents the design and implementation of a mobile broadband satellite access system. In case of the system design, mobile terminal service is considered a critical factor than fixed terminal services, such as resource management, antenna tracking, weak signal recovery. In the paper, mobile broadband interactive satellite access technology system (MoBISAT) is presented. The system network, which is composed of a star network, consists of time division multiplexing-based forward link and multi-frequency time division multiple access-based return link. The MoBISAT provides both Ku-band satellite TV and Ka-band high-speed Internet base on DVB-S/DVB-RCS standards to the passengers and crews for land, maritime and air vehicles. The key factors of hub and mobile terminal are addressed for the design and implementation of the MoBISAT. Especially, the design and implementation of the return link demodulation method, resource management scheme and mobile terminal structure including mobile antenna are described. Copyright © 2006 John Wiley & Sons, Ltd. [source] Four-channel fiber loop ring-down pressure sensor with temperature compensation based on neural networksMICROWAVE AND OPTICAL TECHNOLOGY LETTERS, Issue 8 2010Yang Gao Abstract A four-channel fiber loop ring-down pressure sensor with temperature compensation based on neural networks is described. This fiber ring-down pressure sensor makes use of the principle of time division multiplexing, which consists of series and parallel fiber loops. The laser pulses from four-channels can be acquired by only one detector and the four pressure values are measured synchronously in our experiment. Taking mode dispersion in multimode fiber into consideration, the maximum multiplexing number is discussed. In addition, temperature compensation based on neural networks has been successfully used in our experiment, to eliminate the disturbance of environmental temperature. © 2010 Wiley Periodicals, Inc. Microwave Opt Technol Lett 52: 1796,1799, 2010; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.25326 [source] Optical interface unit,Bridge to the next-generation packet networkBELL LABS TECHNICAL JOURNAL, Issue 1 2003Jeffrey G. Anderson The Lucent Technologies 5ESS® switch has been widely deployed to support voice over time division multiplexing (VoTDM) interfaces to service provider networks. Therefore, the integration of a new voice over packet (VoP) interface into the 5ESS switch architecture is both a complement and a natural extension to the VoTDM interfaces already supported by the 5ESS switch. A new 5ESS peripheral unit, the optical interface unit (OIU), is being developed to support a VoP and a VoTDM trunk interface on the 5ESS switch. The OIU will provide a highly reliable, cost-effective, compact, and energy-efficient solution for both VoP and VoTDM trunks on the 5ESS switch. The OIU will protect a service provider's investment in the 5ESS switch while allowing significant savings, both capital and operational, as the service provider migrates from circuit-based to packet-based voice services in their networks. © 2003 Lucent Technologies Inc. [source] | ||||||||||