High-Throughput and Area-Efficient Rotated and Cyclic Q Delayed Constellations Demapper for Future Wireless Standards

Jafri, Atif Raza; Baghdadi, Amer; Waqas, Muhammad; Najam-ul-Islam, Muhammad

doi:10.1109/access.2017.2660579

Cited by 6 publications

(5 citation statements)

References 11 publications

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“…In contrast to previous works [2, 3, 4, 10, 11, 17, 18, 19, 20, 21] which focused only on the transmitter side, [22] put forth a series of rotation angles to greatly simplify the demapper's design and led recently to a proposal of hardware implementation [23]. This series of angles was independently proposed by [28,29] without considering the demapping and complexity issues.…”

Section: Introductionmentioning

confidence: 88%

Uniformly Projected RCQD QAM: A Low-Complexity Signal Space Diversity Solution Over Fading Channels With or Without Erasures

Arbi

Geller

Yang

et al. 2018

IEEE Trans. on Broadcast.

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Abstract-Rotated and cyclic Q-delayed (RCQD) M -QAM (Quadrature Amplitude Modulation) provides signal space diversity and thus improves system performance over fading channels. However, previously published RCQD solutions were designed without fully considering the high demodulation complexity which prohibits wider applications. In this paper, a complete solution is proposed to reduce complexity for both the modulator and the demodulator. This solution uses a series of rotation angles α =arctan(1/ √ M ) which bring many interesting properties to the RCQD signals. A simplified sphere demapping algorithm is derived for fading channels with and without erasure events. In contrast to the sphere-decoder used for MIMO detection, the radius of the proposed sphere-demapper involves an exact amount of constellation points, thereby ensuring to perform the soft demapping operation successfully. Moreover, when either the in-phase (I) or the quadrature component (Q) is erased, the proposed demapping algorithm performs as well as the fullcomplexity Max-Log algorithm, with a reduced complexity. Compared to the solution currently used in DVB-T2, the proposed method reduces tremendously the computational complexity while still achieving similar performance over fading channels and even better performance over fading erasure channels.

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Section: Introductionmentioning

confidence: 88%

Uniformly Projected RCQD QAM: A Low-Complexity Signal Space Diversity Solution Over Fading Channels With or Without Erasures

Arbi

Geller

Yang

et al. 2018

IEEE Trans. on Broadcast.

View full text Add to dashboard Cite

show abstract

“…(11) Using the max-log approximation in (11), (10) can then be simply evaluated with Euclidean distances as:…”

Section: B Interleaver Estimation At the Receiver Sidementioning

confidence: 99%

“…In contrast, 2D demappers reach a near optimum performance; however the associated complexity is higher and leads to a considerable impact on the receiver design [8]. Recently, the authors in [9] proposed to rotate a QAM with M points by an angle θ = arctan(1/ √ M ) to design a low-complexity high-performance 2D sphere demapper for the so-called Uniformly Projected RCQD (UP-RCQD) constellation; this led to an electronic integration [10].…”

Section: Introductionmentioning

confidence: 99%

Low-Complexity Blind PAPR Reduction for OFDM Systems With Rotated Constellations

Arbi

Geller

2021

IEEE Trans. on Broadcast.

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The high Peak-to-Average Power Ratio (PAPR) of Orthogonal Frequency Division Multiplexing (OFDM) signals leads to a serious system performance degradation. To work around this issue, several algorithms have been proposed in the literature to reduce the PAPR, but, they often suffer from multiple limitations; in particular, the main issue with interleaving techniques is the spectral efficiency loss, as the transmission of a Side Information (SI) is generally required. In contrast to previous works, this paper proposes a blind interleaving technique for OFDM systems with signal space diversity. Indeed, with Rotated and Cyclically Q-Delayed (RCQD) constellations, the In-phase (I) and Quadrature (Q) components of constellations symbols are correlated, which allows the receiver to estimate the interleaver index without any SI. Moreover, to lower down the complexity burden at the receiver side, we first design a blind decoder based on the Minimum Mean Square Error (MMSE) criterion and we then propose a low complexity decoder for the Uniformly Projected RCQD (UP-RCQD) QAM, as this constellation has several interesting structural properties and achieves near optimum BER performance. Simulation results show that our proposal leads to a large PAPR reduction and to a near optimum BER performance that outperforms, over various channels, the solution currently used in DVB-T2. They also underline the good performance of the blind decoding performed with up to 98% of complexity reduction compared to the max-log Maximum Likelihood (ML) estimation.

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“…In the studied demapper implementations, only the throughput delay is considered since it is the main performance metric noted in [36][37][38]. The delay manifests itself as the time between the processing of consecutive input symbols.…”

Section: Symbol Demappermentioning

confidence: 99%

Physical Layer Latency Management Mechanisms: A Study for Millimeter-Wave Wi-Fi

et al. 2021

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Emerging applications in fields such as extended reality require both a high throughput and low latency. The millimeter-wave (mmWave) spectrum is considered because of the potential in the large available bandwidth. The present work studies mmWave Wi-Fi physical layer latency management mechanisms, a key factor in providing low-latency communications for time-critical applications. We calculate physical layer latency in an ideal scenario and simulate it using a tailor-made simulation framework, based on the IEEE 802.11ad standard. Assessing data reception quality over a noisy channel yielded latency’s dependency on transmission parameters, channel noise, and digital baseband tuning. Latency in function of the modulation and coding scheme was found to span 0.28–2.71 ms in the ideal scenario, whereas simulation results also revealed its tight bond with the demapping algorithm and the number of low-density parity-check decoder iterations. The findings yielded tuning parameter combinations for reaching Pareto optimality either by constraining the bit error rate and optimizing latency or the other way around. Our assessment shows that trade-offs can and have to be made to provide sufficiently reliable low-latency communication. In good channel conditions, one may benefit from both the very high throughput and low latency; yet, in more adverse situations, lower modulation orders and additional coding overhead are a necessity.

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High-Throughput and Area-Efficient Rotated and Cyclic Q Delayed Constellations Demapper for Future Wireless Standards

Cited by 6 publications

References 11 publications

Uniformly Projected RCQD QAM: A Low-Complexity Signal Space Diversity Solution Over Fading Channels With or Without Erasures

Uniformly Projected RCQD QAM: A Low-Complexity Signal Space Diversity Solution Over Fading Channels With or Without Erasures

Low-Complexity Blind PAPR Reduction for OFDM Systems With Rotated Constellations

Physical Layer Latency Management Mechanisms: A Study for Millimeter-Wave Wi-Fi

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