06 ci ofdm underwater acoustic communication system
Báo cáo hóa học: " Research Article Intelligent Modified Channel and Frequency Offset Estimation Schemes in Future Generation OFDM-Based Packet Communication Systems" ppt
... estimation performance of the future generation OFDM- based packet communication systems At first, the performance of OFDMbased packet communication systems according to frame structure defined in ... Pad bits Coded OFDM (rate is indicated in SIGNAL) Coded OFDM (BPSK, r = 1/2) PLCP preamble SIGNAL One OFDM symbol 12symbols PSDU Data Variable number of OFDM symbols (Number of OFDM symbol)×4 ... estimation is also a critical problem in OFDM- based packet communication systems, since OFDM signal is more sensitive to frequency offset compared to single carrier system In this chapter we describe...
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Time domain equalization for underwater acoustic OFDM systems with insufficient cyclic prefix
... challenges of underwater communication that scientists and engineers try to overcome Some work has been done in implementing decision feedback equalizer (DFE) on underwater communication systems [5] ... water acoustic links, the channels are as long as a few hundred taps This reduces the bandwidth efficiency of the system This thesis explores methods of reducing the length of CP in OFDM systems, ... longer symbol duration has lower efficiency because CP does not carry data bits Bandwidth efficiency of an OFDM system is given by Nc Nc +Np Figure 2.2: OFDM systems with different CP Let X be...
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MIMO OFDM COMMUNICATION SYSTEMS
... available bandwidth is utilized very efficiently in OFDM systems without causing the ICI (inter-carrier interference) By combining multiple low-data-rate subcarriers, OFDM systems can provide a composite ... to as OFDM Since we aim at performance enhancement for wireless communication systems, we use the term OFDM throughout this thesis Furthermore, we only use the term MIMO -OFDM while explicitly ... are poured into the investigation of OFDM systems Pulse shaping [7, 8], at an interference point view, is beneficial for OFDM systems since the spectrum of an OFDM signal can be shaped to be more...
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Blind channel estimation for MIMO OFDM communication systems
... ZP -OFDM as a comparison to the CP -OFDM Note that through out this thesis, without any further annunciation, the term OFDM means CP -OFDM, and the zero padded -OFDM is denoted as ZP -OFDM In ZP -OFDM, ... review the basic principles of the OFDM systems The mathematical system model of the OFDM systems using the IFFT technique is derived Then we extend it to the general MIMO -OFDM case Although the ... 2.3.2 Principles of OFDM 24 Contents 2.3.3 2.3.4 2.4 FFT Based OFDM and System Model 27 Zero Padded -OFDM 35 MIMO -OFDM System...
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Mobile Communication System Evolution
... first European cellular mobile communication system to be introduced into service [MAC-93] This system was initially developed to provide mobile communication facilities to the rural and less-populated ... developed the AMPS communications system in the late 1970s [BEL-79] The AMPS system was introduced into commercial service in 1983 by AT&T with a 3-month trial in Chicago The system operates in ... Radio Principles and Design, MacMillan Press Ltd., New York, 1993 [MCI-99] Mobile Communications International, Issue 63, July/August 1999 [MCI-99b] The 1999 DECT Supplement, published by MCI in...
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Mobile Communication System Evolution
... CCF CCT CDG CDMA CDPD CEFM CEPT CGI CI CI CI CIMS CM CN CoA COMETS CONUS CPFSK CSCF CT-2 D-AMPS DAB DAB-T DCA DCCH DCS1800 DDB DECT DMT DPC Mobile Satellite Communication Networks Beam Forming ... European Telecommunications Standards Institute European Union European Telecommunication Satellite Organisation Fast FH Fast Associated Control Channel Fixed Channel Assignment Federal Communications ... Gateway Station Control Global System for Mobile Communications GPRS Support Node Geostationary Orbit GPRS Tunnelling Protocol Gateway Transceiver Subsystem Gateway Subsystem High Altitude Long Endurance...
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Principles of Digital Communication Systems and Computer Networks
... phục ảnh hưởng nhiễu Hai khía cạnh đưa Shannon báo “A Maththemathical Theroy of Communication xuất năm 1948 Bell System Technical Journal - nơi đưa lý thuyết thông tin Shannon giải thích hai khía ... trọng cho kỹ sư truyền thông Tài liệu tham khảo C E Shannon "A Mathematical Theory of Communication. " Bell System Technical Journal, Vol 27, 1948 Tất kỹ sư truyền thông phải đọc báo Shannon xem ... tiếng Anh 2,77 bit/ký hiệu, kết hợp ba chữ đại diện 2,77 bit 2.3 Năng suất kênh truyền (Channel capacity): Shannon đưa khái niệm suất kênh truyền , giới hạn liệu truyền qua môi trường Nhiều lỗi việc...
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OFDM Multi-User Communication Over Time-Variant Channels
... spectral efficiency of the system is still acceptable The spectral efficiency of the system is determined by the ratio L/(N + L) Thus, the channel estimation complexity advantage of MC-CDMA is especially ... Figure 2.3 visualizes the OFDM principle through a rotation of the time-frequency plane In a singlecarrier system each symbol occupies the full bandwidth In an multi-carrier system the symbol duration ... code allows to exploit multipath diversity too Coded OFDM is the method of choice for OFDM broadcast systems like DVB-T [19] or for multi-user systems which use time division multiple access (TDMA)...
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Tài liệu Fibre optic communication systems P1 doc
... digital lightwave systems employ OOK in combination with PCM 1.3 Optical Communication Systems As mentioned earlier, optical communication systems differ in principle from microwave systems only in ... optical communication systems This choice is made because of the superior performance of digital transmission systems Lightwave systems offer such an enormous increase in the system capacity (by ... optical communication system It consists of a transmitter, a communication channel, and a receiver, the three elements common to all communication systems Optical communication systems can be classified...
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Tài liệu Fibre optic communication systems P2 pdf
... BL product of such lightwave systems can exceed 100 (Gb/s)-km Indeed, 1.3-µ m telecommunication systems typically operate at a bit rate of Gb/s with a repeater spacing of 40–50 km The BL product ... optical phonons participate in Raman scattering, whereas acoustic phonons participate in Brillouin scattering Both scattering processes result in a loss of power at the incident frequency However, ... powers in optical communication systems are typically below 10 mW, SRS is not a limiting factor for single-channel lightwave systems However, it affects the performance of WDM systems considerably;...
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Tài liệu Fibre optic communication systems P3 pptx
... m and were used in the first generation of fiber-optic communication systems As discussed in Chapter 2, it is beneficial to operate lightwave systems in the wavelength range 1.3–1.6 µ m, where both ... modulated directly at high frequencies (up to 25 GHz) because of a short recombination time associated with stimulated emission Most fiber-optic communication systems use semiconductor lasers as ... the laser Broad-area semiconductor lasers suffer from a number of deficiencies and are rarely used in optical communication systems The major drawbacks are a relatively high threshold current and...
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Tài liệu Fibre optic communication systems P4 doc
... and some ISI invariably occurs 4.3.3 Decision Circuit The data-recovery section of optical receivers consists of a decision circuit and a clockrecovery circuit The purpose of the latter is to ... high-pass filter The decision circuit compares the output from the linear channel to a threshold level, at sampling times determined by the clock-recovery circuit, and decides whether the signal ... h out (t) corresponds to the shape of the voltage pulse V out (t) received by the decision circuit At the decision instant t = 0, h out (t) = 1, and the CHAPTER OPTICAL RECEIVERS 152 Figure 4.13:...
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Tài liệu Fibre optic communication systems P5 doc
... lightwave systems were deployed commercially worldwide beginning in 1996 and allowed a system capacity of 1.6 Tb/s by 2000 for the 160-channel commercial WDM systems The fifth generation of lightwave systems ... the system performance considerably at a bit rate of 40 Gb/s 5.3.2 Terrestrial Lightwave Systems An important application of fiber-optic communication links is for enhancing the capacity of telecommunication ... 60 km of amplifier spacing This system trial led to the deployment of a commercial transpacific cable (TPC–5) that began operating in 1996 The bit rate of fourth-generation systems was extended...
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Tài liệu OPTICAL WIRELESS COMMUNICATION SYSTEM doc
... ABSTRACT Optical communications systems have evolved from lengthy fibers to powerful wireless system This has hence resulted in the use of optical wireless communication system in space communications ... and simulated using a commercial optical system simulator named OptiSystem by Optiwave The findings of this project shows that by using laser satellite communication system, the satellites can ... Writing 27 3.8 Result Analysis Conclusions 27 SYSTEM MODELING 4.1 Introduction 28 4.2 OptiSystem Software 28 4.3 System Model in OptiSystem 29 4.4 System Components 30 4.4.1 IsOWC Transmitter...
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Tài liệu PRINCIPLES OF SPREAD-SPECTRUM COMMUNICATION SYSTEMS ppt
... PRINCIPLES OF SPREAD-SPECTRUM COMMUNICATION SYSTEMS This page intentionally left blank PRINCIPLES OF SPREAD-SPECTRUM COMMUNICATION SYSTEMS By DON TORRIERI Springer ... concise but lucid explanation and derivation of the fundamentals of spread-spectrum communication systems Although spread-spectrum communication is a staple topic in textbooks on digital communication, ... Sequences 6.2 Systems with Random Spreading Sequences Direct-Sequence Systems with PSK Quadriphase Direct-Sequence Systems 6.3 Wideband Direct-Sequence Systems Multicarrier Direct-Sequence System Single-Carrier...
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Tài liệu Fibre optic communication systems P6 ppt
... 1.55 µ m [52]–[56] Their deployment in WDM systems after 1995 revolutionized the field of fiber-optic communications and led to lightwave systems with capacities exceeding Tb/s This section focuses ... amplification for nonreturn-to-zero (NRZ) systems has the potential of doubling the pump-station spacing in comparison with the spacing for the lumped amplifiers [ 106] For long fiber lengths, one should ... given amount of pump power 6.5 SYSTEM APPLICATIONS 261 6.5 System Applications Fiber amplifiers have become an integral part of almost all fiber-optic communication systems installed after 1995 because...
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Tài liệu Fibre optic communication systems P7 ppt
... compensated using DCFs [138] 7.9 High-Capacity Systems Modern WDM lightwave systems use a large number of channels to realize a system capacity of more than Tb/s For such systems, the dispersion-management ... commercially The next section focuses on the techniques commonly used for dispersion management in long-haul systems 7.8 Long-Haul Lightwave Systems This chapter has so far focused on lightwave systems ... this section we discuss the dispersion-management issues relevant for high-capacity systems 7.9 HIGH-CAPACITY SYSTEMS 311 7.9.1 Broadband Dispersion Compensation As discussed in Chapter 8, a...
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