Widely-Linear Nyquist Criteria for DFT-Spread OFDM of Constellation-Rotated PAM Symbols

Choi, Jeonghoon; Kim, Jubum; Cho, Joon Ho; Lehnert, J.S.

doi:10.1109/tcomm.2021.3056106

Cited by 8 publications

(5 citation statements)

References 17 publications

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“…2 and the only parameter to be chosen is the one-tap equalization vector s R . We choose s R to minimize the mean-squared error E{ b−b 2 } subject to zero inter-symbol interference, which is similar to the one-tap equalization vector in [32,Eq. (46)].…”

Section: A Performance Metricsmentioning

confidence: 99%

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Continuous-Phase Modulation for DFT-Spread Localized OFDM

Choi

Cho

Lehnert

2021

IEEE Open J. Commun. Soc.

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Massive machine-type communications to support a large number of low-cost, low-power, and/or low-rate radio-frequency transceivers such as Internet-of-Things (IoT) devices is a major usage scenario of the 5G mobile communication system. To save cost and power, highly nonlinear power amplifiers (PAs) are expected to be used in the devices. However, the envelope fluctuation of the input of a PA may make the output suffer from severe nonlinear distortion. In this paper, a continuous-phase modulation is proposed for discrete-Fourier transform (DFT)-spread localized orthogonal frequency-division multiplexing (OFDM) of π/2-BPSK symbols. In particular, the combination of a spectrum shaping vector and an extra rotation angle is proposed, which enables the use of a receiver that is fully compatible with the current standard. It is shown that the proposed design significantly outperforms the conventional designs in terms of effective signal-to-distortion ratio and error vector magnitude at the cost of a negligible increase in out-of-band emission.

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Section: A Performance Metricsmentioning

confidence: 99%

“…(46)]. The only differences are that the derotation parameter in [32,Eq. (46)] is changed to M/2, and that the observation vector is pruned to have length M , in order to satisfy the compatibility condition.…”

Section: A Performance Metricsmentioning

confidence: 99%

Continuous-Phase Modulation for DFT-Spread Localized OFDM

Choi

Cho

Lehnert

2021

IEEE Open J. Commun. Soc.

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“…In Figure 23, the BER performance of the proposed system is compared with that of various other schemes. For further details, a brief discussion is included on utilized schemes presented by the authors in [32]- [35]. The authors of [32] generalized the Nyquist criteria for ordinary linear modulation to the discrete-Fourier transform (DFT) spread OFDM of constellation-rotated pulse amplitude modulation symbols.…”

Section: Simulation Results and Discussionmentioning

confidence: 99%

“…For further details, a brief discussion is included on utilized schemes presented by the authors in [32]- [35]. The authors of [32] generalized the Nyquist criteria for ordinary linear modulation to the discrete-Fourier transform (DFT) spread OFDM of constellation-rotated pulse amplitude modulation symbols. In [33], the authors propose an OFDM scheme which incorporates index modulation, spread spectrum, and C-transform techniques and strongly emphasizes the BER performance of the proposed OFDM, conventional OFDM systems, and several other similar systems.…”

Section: Simulation Results and Discussionmentioning

confidence: 99%

UAV-Aided Transceiver Design for Secure Downlink OW-DFTs-OFDM System: A Multi-User mmWave Application

et al. 2022

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Unmanned aerial vehicle (UAV)-based communication system design has already attracted substantial interest due to UAV flexibility in deployment, cost effectiveness, and in-built line-of-sight air-toground channels. However, there is a persistent issue of security threats associated with the broadcast nature of UAV: physical layer security (PLS) can be introduced to enhance the secrecy performance in that regard.In the system proposed here, the combined effect of 3D fractional-order Liu chaotic system and 3D fractionalorder Li chaotic system is introduced to enhance the PLS of the UAV-to-ground communication network. In addition, to reduce multi-user interference (MUI), efficient orthogonal variable spreading factor (OVSF) codes are integrated with a zero forcing (ZF) scheme. Moreover, to improve bit error rate (BER), a combined MUI signal discrimination and ZF signal detection scheme is introduced, strengthened by various channel coding techniques with multi-user beamforming weighting. The numerical outcomes establish the efficacy of the proposed system in terms of PLS and improvement of data rate with signal-to-interference-plus-noise ratio. This approach achieved an out-of-band emission reduction of 119 dB. Furthermore, an improved BER of 1 × 10 −4 is achieved in 16-QAM for a signal-to-noise ratio of 6 dB.INDEX TERMS Millimeter-wave, orthogonal frequency-division multiplexing, orthogonal variable spreading factor, overlap-windowed discrete Fourier transform, physical layer security, unmanned aerial vehicle, zero forcing precoding.

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“…After reviewing the existing approaches, the following research gap has been observed and are currently stated in the form of research problem: i) Existing schemes requires more sample collection to reconstruct the signal while modelling (especially where machine learning has been used viz [20], [23], [34], [39], [41]); ii) The studies have been individually carried out over a constrained research approach, where the outcome is not applicable for dynamic environment situation [36], [37]; iii) OFDM has been identified as one the common target for improvement using different variant of spread spectrum (especially using discrete Fourier transform spread e.g. [27]), however, there is not much discussion about selection of robust signal under variable rate of traffic or cell density; iv) There is a consideration that PU is located in the same cell as that of secondary user SU without considering the probability that it is also characterized by interference, as well as the fading characteristics of the PUs-SU links that is not addressed [38], [40]; v) Mostly limited to theoretical analysis without much effective benchmarking; vi) Existing models involve more operating cost and may associate with computational overhead [42]; vii) None of the existing studies are found to address problems when the communicating environment is associated with artifacts e.g. fading, shadowing, higher computational cost, and collisions.…”

Section: Introductionmentioning

confidence: 99%

Novel evaluation framework for sensing spread spectrum in cognitive radio

Bellary,

Budyal

2023

IJECE

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<span lang="EN-US">The cognitive radio network is designed to cater to the optimization demands of restricted spectrum availability. A review of existing literature on spectrum sensing shows that there is still a broader scope for its improvement. Therefore, this paper introduces an efficient computational framework capable of evaluating the effectiveness of the spread spectrum concept in the context of cognitive radio network in a more scalable and granular way. The proposed method introduces a dual hypothesis using a different set of dependable parameters to emphasize the detection of optimal energy for a low signal quality state over the noise. The proposed evaluation framework is benchmarked using a statistical analysis method not present in any existing approaches toward spread spectrum sensing. The simulated outcome of the study exhibits that the proposed system offers a significantly better probability of detection than the current system using a simplified evaluation scheme with multiple test parameters.</span>

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Widely-Linear Nyquist Criteria for DFT-Spread OFDM of Constellation-Rotated PAM Symbols

Cited by 8 publications

References 17 publications

Continuous-Phase Modulation for DFT-Spread Localized OFDM

Continuous-Phase Modulation for DFT-Spread Localized OFDM

UAV-Aided Transceiver Design for Secure Downlink OW-DFTs-OFDM System: A Multi-User mmWave Application

Novel evaluation framework for sensing spread spectrum in cognitive radio

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