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Book ChapterDOI

Introduction to Orthogonal Frequency Division Multiplexing

24 Nov 2006-pp 19-39

Abstract: This chapter contains sections titled: Introduction Principles of QAM-OFDM Modulation by DFT Transmission via Bandlimited Channels Basic OFDM Modem Implementations Cyclic OFDM Symbol Extension Decision-Directed Adaptive Channel Equalisation OFDM Bandwidth Efficiency Chapter Summary and Conclusion
Topics: Orthogonal frequency-division multiplexing (56%), Spectral efficiency (53%), Modulation (53%), Nyquist rate (53%)

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LUND UNIVERSITY
PO Box 117
221 00 Lund
+46 46-222 00 00
An introduction to orthogonal frequency-division multiplexing
Edfors, Ove; Sandell, Magnus; van de Beek, Jan-Jaap; Landström, Daniel; Sjöberg, Frank
1996
Link to publication
Citation for published version (APA):
Edfors, O., Sandell, M., van de Beek, J-J., Landström, D., & Sjöberg, F. (1996).
An introduction to orthogonal
frequency-division multiplexing
. (Div. of Signal Processing, Research Report; Vol. TULEA 1996:16). Luleå
University of Technology.
Total number of authors:
5
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IS ON SIGNAL PROCESSING AREAS PURSUED BY OUR RESEARC H GROUP AT ,ULE¥ 5NIV ERSITY OF 4EC HNOLOGY
7E PRESENT AN HISTORICAL BACKGROUND AND SOME FREQUEN TLY USED SYSTEM MODELS 4YPICAL AREAS OF
AP PLIC A TIO NS AR E ALSO DESCRIBED BOTH WIR E LES S AND WIRED )N ADDITION TO THE GENER A L OVER VIEW
THE ADDRESSED AREAS INCLUDE SYNCHRONIZATION CHANNEL ESTIMATION AND C HANNEL CODING "OTH
TIME AND FREQUENCY SYNC HRONIZATION ARE DESCRIBED AND THE EdECTS OF SYNC HRONIZATION ERRORS
ARE PRESEN TED $IdERENT TYPES OF C HANNEL ESTIMATORS ARE DESCRIBED WHERE THE FOCUS IS ON LOW
COMPLEXITY ALGORITHMS AND IN THIS CON TEXT ADVAN TAGES AND DISADVAN TAGES OF COHERENT AND
DIdERENTIAL MODULATION ARE ALSO DISCUSSED #HANNEL CODING IS DESCRIBED BOTH FOR WIRELESS AND
WIRED SYSTEMS AND POIN TERS ARE INCLUDED TO EV ALUATION TOOLS AND BITLOADING ALGORITHMS !N
EXTENSIV E BIBLIOGRAPH Y IS ALSO INCLUDED


Citations
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Journal ArticleDOI
Tianqi Mao1, Zhaocheng Wang1, Qi Wang1, Sheng Chen2  +1 moreInstitutions (2)
TL;DR: A dual-mode OFDM technique is proposed, which is combined with index modulation and enhances the attainable throughput of conventional index-modulation-based OFDM and achieves a considerably better BER performance than other OFDM systems using index modulation, while imposing the same or lower computational complexity.
Abstract: Index modulation has become a promising technique in the context of orthogonal frequency division multiplexing (OFDM), whereby the specific activation of the frequency domain subcarriers is used for implicitly conveying extra information, hence improving the achievable throughput at a given bit error ratio (BER) performance. In this paper, a dual-mode OFDM technique (DM-OFDM) is proposed, which is combined with index modulation and enhances the attainable throughput of conventional index-modulation-based OFDM. In particular, the subcarriers are divided into several subblocks, and in each subblock, all the subcarriers are partitioned into two groups, modulated by a pair of distinguishable modem-mode constellations, respectively. Hence, the information bits are conveyed not only by the classic constellation symbols, but also implicitly by the specific activated subcarrier indices, representing the subcarriers’ constellation mode. At the receiver, a maximum likelihood (ML) detector and a reduced-complexity near optimal log-likelihood ratio-based detector are invoked for demodulation. The minimum distance between the different legitimate realizations of the OFDM subblocks is calculated for characterizing the performance of DM-OFDM. Then, the associated theoretical analysis based on the pairwise error probability is carried out for estimating the BER of DM-OFDM. Furthermore, the simulation results confirm that at a given throughput, DM-OFDM achieves a considerably better BER performance than other OFDM systems using index modulation, while imposing the same or lower computational complexity. The results also demonstrate that the performance of the proposed low-complexity detector is indistinguishable from that of the ML detector, provided that the system’s signal to noise ratio is sufficiently high.

191 citations


Cites background from "Introduction to Orthogonal Frequenc..."

  • ...It is also capable of offering a low-complexity high-performance solution for mitigating the inter-symbol interference (ISI) caused by a dispersive channel [2], [3]....

    [...]

  • ...by the mapper A are determined by the two index bits, which assume the values of [0, 0], [0, 1], [1, 0] and [1, 1], as I((1)) A = [1, 2], I (2) A = [2, 3], I (3) A = [3, 4] and I((4)) A = [1, 4], while the other subcarriers are modulated by the mapper B....

    [...]


Book
27 Jun 2012
TL;DR: This book presents OFDM-inspired systems that are able to, at most, halve the amount of redundancy used by OFDM systems while keeping the computational complexity comparable, and memoryless linear time-invariant transceivers with reduced redundancy.
Abstract: The demand for data traffic over mobile communication networks has substantially increased during the last decade. As a result, these mobile broadband devices spend the available spectrum fiercely, requiring the search for new technologies. In transmissions where the channel presents a frequency-selective behavior, multicarrier modulation (MCM) schemes have proven to be more efficient, in terms of spectral usage, than conventional modulations and spread spectrum techniques. The orthogonal frequency-division multiplexing (OFDM) is the most popular MCM method, since it not only increases spectral efficiency but also yields simple transceivers. All OFDM-based systems, including the single-carrier with frequency-division equalization (SC-FD), transmit redundancy in order to cope with the problem of interference among symbols. This book presents OFDM-inspired systems that are able to, at most, halve the amount of redundancy used by OFDM systems while keeping the computational complexity comparable. Such systems, herein called memoryless linear time-invariant (LTI) transceivers with reduced redundancy, require low-complexity arithmetical operations and fast algorithms. In addition, whenever the block transmitter and receiver have memory and/or are linear time-varying (LTV), it is possible to reduce the redundancy in the transmission even further, as also discussed in this book. For the transceivers with memory it is possible to eliminate the redundancy at the cost of making the channel equalization more difficult. Moreover, when time-varying block transceivers are also employed, then the amount of redundancy can be as low as a single symbol per block, regardless of the size of the channel memory. With the techniques presented in the book it is possible to address what lies beyond the use of OFDM-related solutions in broadband transmissions. Table of Contents: The Big Picture / Transmultiplexers / OFDM / Memoryless LTI Transceivers with Reduced Redundancy / FIR LTV Transceivers with Reduced Redundancy

15 citations


ReportDOI
01 Jun 2005
TL;DR: A study of the feasibility and initial hardware design for transmitting data over aircraft power lines and the intent is to significantly reduce the wiring in the aircraft instrumentation system.
Abstract: : This paper introduces a study of the feasibility and initial hardware design for transmitting data over aircraft power lines. The intent of this design is to significantly reduce the wiring in the aircraft instrumentation system. The potential usages of this technology include Common Airborne Instrumentation System (CAIS) or clock distribution. Aircraft power lines channel characteristics are presented and Orthogonal Frequency Division Multiplexing (OFDM) is introduced as an attractive modulation scheme for high-speed power line transmission. A design of a full-duplex transceiver with accurate frequency planning is then discussed. A general discussion of what communications protocols are appropriate for this technology is also provided.

5 citations


01 Oct 2006
TL;DR: This paper presents a practical implementation of a hardware design for transmission of data over aircraft power lines using Orthogonal frequency division multiplexing (OFDM), the most appropriate technology for high-speed data transmission on aircraft power Lines.
Abstract: This paper presents a practical implementation of a hardware design for transmission of data over aircraft power lines. The intent of such hardware is to significantly reduce the wiring in the aircraft instrumentation system. The potential usages of this technology include pulse code modulation (PCM), Ethernet and other forms data communications. Details of the fieldprogrammable gate array (FPGA) and printed circuit board (PCB) designs of the digital and analog front end will be discussed. The power line is not designed for data transmission. It contains considerable noise, multipath effects, and time varying impedance. Spectral analysis data of an aircraft is presented to indicate the difficulty of the problem at hand. A robust modulation is required to overcome the harsh environment and to provide reliable transmission. Orthogonal frequency division multiplexing (OFDM) has been used in power line communication industry with a great deal of success. OFDM has been deemed the most appropriate technology for high-speed data transmission on aircraft power lines. Additionally, forward error correction (FEC) techniques are discussed.

3 citations


Journal ArticleDOI
TL;DR: Performance evaluation of Adaptive Modulation and Coding (AMC) in downlink of an orthogonal frequency division multiple access (OFDMA) network, considering Partial Usage of Sub-channels (PUSC) suggests better performance for AMC over individual MCS in all channel environments.
Abstract: 3 Abstract: The recent demand for higher data rate services from wireless network users is overwhelming. Social media influx as well as the proliferation of broadband enabled smart-phones, tablet computers and other newly improved wireless devices has erupted a new trend in wireless network traffic need where average capacity and speed is no longer appreciable. In order to cope with this trend in traffic requirement, wireless network operators are considering a gradual rollover of an existing third generation (3G) network to a fourth generation (4G) network with orthogonal frequency division multiple access (OFDMA) based technologies such as Fourth Generation Long Term Evolution (4G LTE) and Worldwide Interoperability for Microwave Access (WiMAX). This paper is devoted to the performance evaluation of Adaptive Modulation and Coding (AMC) in downlink of an orthogonal frequency division multiple access (OFDMA) network, considering Partial Usage of Sub-channels (PUSC). By using MATLAB Simulink and Origin 61, the performance of Bit Error Rate (BER) and Spectral Efficiency in two channel environments, i.e. non-fading and fading channels were examined. Results suggest better performance for AMC over individual MCS in all channel environments. Moreover, non-fading Addictive White Gaussian Noise (AWGN) channels significantly perform better than fading (Rayleigh and Rician) channels. In Rician channel environment, however, flat fading Rician channels perform better than frequency selective Rician channel which interestingly records a degraded performance against Rayleigh channels. Keywords: third generation (3G), fourth generation (4G), Orthogonal Frequency Division Multiple Access (OFDMA), Long Term Evolution (LTE), Worldwide Interoperability for Microwave Access (WiMAX), Bit Error Rate (BER), Adaptive Modulation and Coding (AMC), Partial Usage of Sub-channels (PUSC), Rayleigh channels and Rician channels

3 citations


Cites methods from "Introduction to Orthogonal Frequenc..."

  • ...The orthogonality of each subcarrier in OFDM according to [15] is given by:...

    [...]


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