orthogonal frequency division multiplexing for optical communications

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... carrier frequency domain equalization (SCFDE) over a diffuse optical wireless (DOW) communications. Recently orthogonal frequency division multiplexing (OFDM) has been applied to DOW communications. However, ... receivers for optical signals. These opto electronic devices are cheaper as compared to RF equipments. Orthogonal frequency division multiplexing (OFDM) modulation is a promising modulation scheme for ... the OFDM systems for DOW transmission, the asymmetrically clipped optical orthogonal frequency division multiplexing (ACO-OFDM) [7]hasbeen shown to be more efficient in terms of optical power than the...

Ngày tải lên: 21/06/2014, 08:20

... 9 Elementary decoder for row 1 Elementary decoder for row 2 Elementary decoder for row N Elementary decoder for column 1 Elementary decoder for column 2 Elementary decoder for column N Elementary decoder for ... signals Elementary decoder for row 1 Elementary decoder for row 2 Elementary decoder for row N Elementary decoder for column 1 Elementary decoder for column 2 Elementary decoder for column N FPGA XC5VLX330 Connection ... signals Elementary decoder for row 1 Elementary decoder for row 2 Elementary decoder for row N Elementary decoder for column 1 Elementary decoder for column 2 Elementary decoder for column N SERDES...

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Ngày tải lên: 07/08/2014, 06:20

... spatial relationships as well. Space -Frequency Transform Map For a static channel, we may extend the time -frequency transform map in Figure 2.9 for the space -frequency relationships shown in Figure ... these definitions. |h( )|f ~ frequency, f f c B c Frequency Selectivity V 0 Figure 2.6: Example of a frequency- varying channel. The loss of frequency coherence in a wireless communications system is ... space -frequency channel models. CHAPTER 2. FOUNDATIONS OF STOCHASTIC CHANNEL MODELING 27 Table 2.2: Fourier transform definitions for each channel dependency. Domain Pairs Transform Inverse Transform frequency, ...

Ngày tải lên: 20/11/2012, 11:36

... Models for the Physical Layer and for User Traffic Generation 221 5.1 How to Account for the Physical Layer? 221 5.1.1 What to Account For and How? 221 5.1.2 Using Approximations for Error Performance ... Network Layer O ODMA Opportunity Driven Multiple Access OFDM Orthogonal Frequency- Division Multiplexing OSI Open Systems Interconnection OVSF Orthogonal Variable Spreading Factor (UMTS) P P-CCPCH Primary ... access delay for S-ALOHA D acc Data access delay D CDM Transfer delay for code -division multiplexing D d Packet interarrival time D gap Mean talk gap duration D max Delay threshold for packet dropping...

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Ngày tải lên: 06/09/2013, 07:50

... New York, 1999. 126 VoIP FOR GLOBAL COMMUNICATIONS 8 VoIP FOR GLOBAL COMMUNICATIONS1 This Chapter discusses how IP-based voice communications can be deployed for global communications in multinational ... a destination, and so on. Therefore, addi- tional resources need to be allocated for these hardware and software plat- forms. The network performance–related information collected using these ... architecture for a packet-based global network for advanced or enhanced VoIP and POTS services in a multinational corporation.) (Source: Adapted from Fig. 3-8) 120 VoIP FOR GLOBAL COMMUNICATIONS ...

Ngày tải lên: 30/09/2013, 07:20

... core functions as a master processor for global control and for processing of tasks such as variable length encoding and quantization. To improve the performance for typical video coding schemes, ... Normalized silicon area and throughput for dedicated DCT circuits. c  1999 by CRC Press LLC VLSIArchitecturesforImage Communications P.Pirsch Laboratoriumfur Informationstechnologie, UniversityofHannover W.Gehrke PhilipsSemiconductors 59.1Introduction 59.2RecentCodingSchemes 59.3ArchitecturalAlternatives 59.4EfciencyEstimationofAlternativeVLSIImplementations 59.5DedicatedArchitectures 59.6ProgrammableArchitectures IntensivePipelinedArchitectures ã ParallelDataPaths ã Co- processorConcept 59.7Conclusion Acknowledgment References 59.1 ... Introduction Videoprocessinghasbeenarapidlyevolvingeldfortelecommunications,computer,andmedia industries.Inparticular,forrealtimevideocompressionapplicationsagrowingeconomicalsigni- canceisexpectedforthenextyears.BesidesdigitalTVbroadcastingandvideophone,servicessuch asmultimediaeducation,teleshopping,orvideomailwillbecomeaudiovisualmassapplications. Tofacilitateworldwideinterchangeofdigitallyencodedaudiovisualdata,thereisademandfor internationalstandards,deningcodingmethods,andtransmissionformats.Internationalstan- dardizationcommitteeshavebeenworkingonthespecicationofseveralcompressionschemes.The JointPhotographicExpertsGroup(JPEG)oftheInternationalStandardsOrganization(ISO)has speciedanalgorithmforcompressionofstillimages[4].TheITUproposedtheH.261standardfor videotelephonyandvideoconference[1].TheMotionPicturesExpertsGroup(MPEG)ofISOhas completeditsrststandardMPEG-1,whichwillbeusedforinteractivevideoandprovidesapicture qualitycomparabletoVCRquality[2].MPEGmadesubstantialprogressforthesecondphaseof standardsMPEG-2,whichwillprovideaudiovisualqualityofbothbroadcastTVandHDTV[3]. Besidestheavailabilityofinternationalstandards,thesuccessfulintroductionofthenamedservices dependsontheavailabilityofVLSIcomponents,supportingacostefcientimplementationofvideo compressionapplications.Inthefollowing,wegiveashortoverviewofrecentcodingschemesand discussimplementationalternatives.Furthermore,theefciencyestimationofarchitecturalalter- nativesisdiscussedandimplementationexamplesofdedicatedandprogrammablearchitecturesare presented. c 1999byCRCPressLLC ...

Ngày tải lên: 25/10/2013, 02:15

... spectrum. Basically, there were time division (TDMA - Time Division Multiple Access), frequency division (OFDM - Orthogonal Frequency Division Multiple Access), and code division proposals (CDMA). In ... responsible for operation and maintenance (monitoring, performance data, alarms, and so forth) within the RNS. ã SGSN - The SGSN is responsible for session management, producing charging information, ... Chapter 7 debates this. 1.4 Economic Reasons for 'IP for 3G' As already indicated, IP for 3G is about reducing costs. There is nothing that IP for 3G will enable that cannot already be...

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... Center for Telecom- munications and Information Systems Laboratory, Stanford University, Stanford, CA, June 1994. [2] Second workshop on smart antennas in wireless mobile communications, Center for ... Telecom- munications and Information Systems Laboratory, Stanford University, Stanford, CA, July 20-21, 1995. [3] Third workshop on smart antennas in wireless mobile communications, Center for Telecom- munications ... [12, 30, 55] for more details. For a linear modulation (e.g., BPSK), we can write u(t) =  k g(t − kT )s(k) (68.2) where g(·) is the pulse shaping waveform and s(k)represents the information bits. In...

Ngày tải lên: 16/12/2013, 04:15

... for today’s next generation networks, look to ADC’s CWDM solutions to help you win the race. Metro Transport Ring Using CWDM HEADEND RESIDENTIAL Optical Node Hub Hub Hub Hub Optical Node Optical Node Optical Node INDUSTRIAL WIRELESS HANDOFF HIGH-RISE ... CWDM HEADEND RESIDENTIAL Optical Node Hub Hub Hub Hub Optical Node Optical Node Optical Node INDUSTRIAL WIRELESS HANDOFF HIGH-RISE MDU/ BUSINESS Satellite Uplink F i b e r L i n e W a v e l e n g t h s The CWDM Advantage ADC Coarse Wave Division Multiplexing ... Coarse Wavelength Division Multiplexing (CWDM) Generate More Revenue with Less Fiber Here's How it Works In simple...

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... the exciting force provide its frequency control. In this way, operation of EVCD becomes independent of network supply frequency. The paper presented a possible solution low -frequency IGBT ... and frequency in a wide range is achieved by means of suitable power converter and corresponding controller. The range of amplitude oscillation for most EVCD is 0.1mm-100mm, while the frequency ... 2009 NOVI SAD, REPUBLIC OF SERBIA, October 28 th - 30 th , 2009 LOW FREQUENCY IGBT CONVERTER FOR CONTROL EXCITING FORCE OF ELECTROMAGNETIC VIBRATORY CONVEYORS Željko Despotović, Aleksandar...

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