Polynomial cancellation coding of OFDM to reduce intercarrier interference due to Doppler spread

Armstrong, Jean; Grant, Peter; Povey, G.J.R.

doi:10.1109/glocom.1998.776492

Cited by 77 publications

(43 citation statements)

References 3 publications

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“…Fig. 9 provides clear evidence that the "basis expansion model" (BEM) constructed from a rectangularly-windowed si- 3 Since the MSE of the O(N) (linear) equalizer in [14] is lower bounded by that of the linear MMSE estimator (12), it is clear that the O(N) equalizers SIE, BIE, and SDF significantly outperform the one in [14]. nusoidal basis [16], [20] and truncated to include no more than elements, where , is ineffective in its description of doubly selective WSSUS Rayleigh channels; receivers designed around this BEM will perform poorly on true (i.e., nonapproximate) channels.…”

Section: Numerical Results and Discussionmentioning

confidence: 99%

“…7 and 8 compare the subcarrier-averaged MSE performance of the SDF, BDF, BIE, and SIE iterative symbol estimation algorithms proposed in Section IV-C3 to the MFB, AMFB, and linear MMSE estimator (12). Each trace represents the average of 5000 channel/data realizations.…”

Section: Numerical Results and Discussionmentioning

confidence: 99%

“…With an LTV channel, the MMSE and ZF estimators (12) and (13) require nontrivial matrix inversion. Inversion algorithms that make use of the Hermitian Toeplitz structure in (12) still require at least operations [23], making them impractical for large .…”

Section: A Classical Methodsmentioning

confidence: 99%

“…The linear MMSE and zero-forcing (ZF) estimates [15] are given in (12) and (13), respectively, assuming , , , , and knowledge of the channel.…”

Section: A Classical Methodsmentioning

confidence: 99%

“…While the vast majority of OFDM literature ignores intrasymbol channel variation, several OFDM modifications have been proposed to cope with the resulting inter-carrier interference (ICI). Armstrong et al [12] suggested the use of polynomial cancellation coding (PCC) [13], which is typically used to suppress ICI from carrier frequency offset. Because channel-variation yields a different ICI structure than does frequency offset, however, the applicability of PCC is quite limited.…”

Section: Introductionmentioning

confidence: 99%

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Low-Complexity Equalization of OFDM in Doubly Selective Channels

Schniter

2004

IEEE Trans. Signal Process.

442

438

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Abstract-Orthogonal frequency division multiplexing (OFDM) systems may experience significant inter-carrier interference (ICI) when used in time-and frequency-selective, or doubly selective, channels. In such cases, the classical symbol estimation schemes, e.g., minimum mean-squared error (MMSE) and zero-forcing (ZF) estimation, require matrix inversion that is prohibitively complex for large symbol lengths. An analysis of the ICI generation mechanism leads us to propose a novel two-stage equalizer whose complexity (apart from the FFT) is linear in the OFDM symbol length. The first stage applies optimal linear preprocessing to restrict ICI support, and the second stage uses iterative MMSE estimation to estimate finite-alphabet frequency-domain symbols. Simulation results indicate that our equalizer has significant performance and complexity advantages over the classical linear MMSE estimator in doubly selective channels.Index Terms-Doubly dispersive channel, doubly selective channel, equalization, intercarrier interference, OFDM.

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Section: Numerical Results and Discussionmentioning

confidence: 99%

Section: Numerical Results and Discussionmentioning

confidence: 99%

Section: A Classical Methodsmentioning

confidence: 99%

“…The linear MMSE and zero-forcing (ZF) estimates [15] are given in (12) and (13), respectively, assuming , , , , and knowledge of the channel.…”

Section: A Classical Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Low-Complexity Equalization of OFDM in Doubly Selective Channels

Schniter

2004

IEEE Trans. Signal Process.

442

438

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Enhanced OFDM for fragmented spectrum use in 5G systems

Loulou

Renfors

2014

Trans. Emerging Tel. Tech.

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Most of the recent and emerging wireless systems have selected orthogonal frequency division multiplexing (OFDM) scheme as the basis for the physical layer due to its flexibility and robustness. OFDM is commonly considered also as the first candidate technology for advanced cognitive radio, dynamic spectrum use and fragmented coexistence scenarios, including the 5G system development. Nevertheless, OFDM has the problem of high‐power spectral sidelobes around the active subcarriers, which limit its feasibility in fragmented spectrum use and asynchronous frequency division multiple access operation. Therefore, various sidelobe suppression techniques have been proposed in the literature to mitigate these effects. This paper investigates four different suppression techniques: time‐domain windowing, cancellation carrier method, subcarrier weighting and polynomial cancellation coding, as well as their combinations. These methods are elaborated for a practical heterogeneous fragmented spectrum use scenario based on 5‐MHz 3GPP Long‐Term Evolution (LTE), proposing various enhancements to achieve effective suppression in narrow gaps with affordable complexity. In addition to the spectral characteristics, also, the possible side effects are evaluated in details, considering peak‐to‐average power ratio characteristics, error rate performance, computational complexity and resources usage. Copyright © 2014 John Wiley & Sons, Ltd.

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Analysis of Doppler Spread Perturbations in OFDM(A) Systems

Robertson

Kaiser

2000

Trans Emerging Tel Tech

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Abstract. We analyze the effects of Doppler spread in mobile channels on Orthogonal Frequency Division Multiplex (OFDM) systems. This is important, since channel variations during one OFDM symbol cause Inter Sub-carrier Interference (ICI) in OFDM systems, which degrades the performance, since ICI can be seen as additional near-Gaussian noise. The analysis is presented and closed-form results are given for numerous important practical Doppler spread encountered in mobile channels and applications such as mobile reception of DVB-T. We also show that for the case of asymmetrical Doppler spreads, the frequency correction of the receiver can be adjusted so as to minimize the ICI. To extend our work to OFDM(A) mobile radio systems where many users' contributions to the ICI overlap, we have introduced the concept of an equivalent single-user which causes the total ICI, in order to use the same analytical framework, and compared the uplink and downlink cases. Simulation results confirm our analysis and show the importance of the analytical tool to perform realistic system analysis without having to resort to time consuming time-domain simulations.

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Polynomial cancellation coding of OFDM to reduce intercarrier interference due to Doppler spread

Cited by 77 publications

References 3 publications

Low-Complexity Equalization of OFDM in Doubly Selective Channels

Low-Complexity Equalization of OFDM in Doubly Selective Channels

Enhanced OFDM for fragmented spectrum use in 5G systems

Analysis of Doppler Spread Perturbations in OFDM(A) Systems

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