The History of Orthogonal Frequency Division Multiplexing

LaSorte, Nick; Barnes, W. J.; Refai, Hazem H.

doi:10.1109/glocom.2008.ecp.690

Cited by 32 publications

(14 citation statements)

References 13 publications

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“…A practical implementation could therefore start with the evaluation of -without the premultiplication with (4). Likewise, the MMSE-ZR can be implemented as a post-processing of the MMSE-FD-EXT.…”

Section: Methodsmentioning

confidence: 99%

Frequency-domain equalizers with zero restoration for zero-padded block transmission with high SNR

Cuypers

Moonen

2016

J Wireless Com Network

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This paper focuses on the equalization of block transmissions with zero pad (ZP). If the channel impulse response length does not exceed the ZP length, it is possible to construct zero-forcing equalizers (ZFEs). Improved performance may be achieved using a minimum mean squared error (MMSE) equalizer. However, these equalizers are computationally intensive when a time-domain implementation is used. While the frequency-domain implementation of a ZFE has a lower complexity, it is prone to-potentially infinite-noise enhancement in the presence of spectral zeros. The MMSE equalizer in the frequency domain performs better by limiting the noise enhancement but still loses all information stored at the spectral zeros. This paper presents a method to exploit the redundancy of the padding to recover this lost information, leading to two new frequency-domain equalizers, a ZFE and an MMSE-like equalizer. These two equalizers are evaluated through simulations. They have a performance close to the time-domain equalizers, while maintaining the low complexity of the original frequency-domain equalizers. The equalizers are especially useful for scenarios with a high signal-to-noise ratio (SNR), where the performance is not limited by the presence of noise, but by the absence of the information stored in the spectral zeros. In practice, this means an SNR >30 dB. With minor modifications, the equalizers can also be applied if the ZP is replaced by a unique word (UW).

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Section: Methodsmentioning

confidence: 99%

Frequency-domain equalizers with zero restoration for zero-padded block transmission with high SNR

Cuypers

Moonen

2016

J Wireless Com Network

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“…In OFDM the subcarriers are chosen in such a way that they are mutually orthogonal and which eliminates the cross talk between the subcarriers [7]. Equation 2 Stage V is the guard interval insertion, which affixes a cyclic prefix to the beginning of every OFDM symbols to diminish the effect of ISI and ICI [9].…”

Section: Overview Of An Ofdmmentioning

confidence: 99%

An Efficient Orthogonal Frequency Division Multiplexing (OFDM) System and Performance Analysis of Digital Audio Broadcasting (DAB) System

Drakshayini¹,

Singh²

2016

IJCA

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The foremost objective of digital modulation today is to provide high spectral efficiency. OFDM is a multicarrier digital modulation technique which offers high spectral efficiency. In this paper an efficient OFDM system under AWGN channel is designed using MATLAB and performance analysis is done for the system by evaluating BER and SNR. Frequency Modulation (FM) mainly suffers from Multipath fading and ISI. FM is suitable for fixed reception but it is not suitable for mobile reception since it suffers loss of broadcasting quality. These issues are overcome in DAB. DAB is a digital radio or high definition radio which offers high audio quality. This paper also proposes that designing DAB using OFDM under Rayleigh fading channel. Performance analysis of DAB system is done for the audio input by evaluating BER and SNR.

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“…To avoid inter symbol interference (ISI), due to the delay spread of the channel, a cyclic prefix (CP) is also added at the beginning of every OFDM frame during the guard interval (GI) [9]. The cyclic prefix is just a copy of Q samples, i.e.…”

Section: B Ofdm Encodingmentioning

confidence: 99%

“…The main advantages of OFDM are its spectral efficiency and simple implementations based on the FFT [9]. However, when using linear codes (eg.…”

Section: Introductionmentioning

confidence: 99%

Low PAPR and spatial diversity for OFDM schemes by using L2-orthogonal CPM ST-codes with fast decoding

Hisojo¹,

Lebrun²,

Deneire³

2014

2014 IEEE Latin-America Conference on Communications (LATINCOM)

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International audienceOrthogonal Frequency Division Multiplexing (OFDM) is a popular modulation technique that provides high data rates and good robustness against frequency selective fading. Space-Time Block Coding (STBC) is an efficient way to introduce space-time diversity in Multiple-Input Multiple-Output (MIMO) systems. Using non-linear modulations such as Continuous Phase Modulation (CPM) with its constant envelope and continuous phase properties could be a solution to construct MIMO OFDM systems and to avoid the structural limitations of linear codes and alleviate the typical PAPR issue of OFDM. However, a major issue with CPM based systems may remain: the decoding complexity. In this paper, we introduce a new space-time-frequency diversity technique based on L2-orthogonal multi-h CPM Space-Time codes designed for OFDM transmission. We benchmark these codes under Rayleigh frequency selective channels and show how they achieve full spatial diversity at full rate for any number of antennas, good spectral compactness and also robustness to frequency fading. Furthermore, the decoding complexity is highly reduced and even made linear in the number of antennas thanks to the orthogonality properties

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The History of Orthogonal Frequency Division Multiplexing

Cited by 32 publications

References 13 publications

Frequency-domain equalizers with zero restoration for zero-padded block transmission with high SNR

Frequency-domain equalizers with zero restoration for zero-padded block transmission with high SNR

An Efficient Orthogonal Frequency Division Multiplexing (OFDM) System and Performance Analysis of Digital Audio Broadcasting (DAB) System

Low PAPR and spatial diversity for OFDM schemes by using L2-orthogonal CPM ST-codes with fast decoding

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