Design of High-SNR Multidimensional Constellations for Orthogonal Transmission in a Nakagami- ${m}$ Fading Channel

Khoshnevis, Hossein; Marsland, Ian; Yanıkömeroğlu, Halim

doi:10.1109/access.2017.2772170

Cited by 7 publications

(6 citation statements)

References 45 publications

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“…It can be seen that our VNOMA scheme presents capacity improvement comparing to the power-balanced NOMA (termed as NOMA-PB) and TDMA. Furthermore, we compare our scheme with the multidimensional constellations for orthogonal transmission in [16]. As we can see from Figure 2, our proposed scheme presents the same performance as 16-2D constellation.…”

Section: Experiments Setup and Simulation Resultsmentioning

confidence: 81%

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Performance Improvement on Nonorthogonal Multiple Access without CSIT

Xia

Zhou

Meng

2020

Wireless Communications and Mobile Computing

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In this paper, a downlink virtual-channel-optimization nonorthogonal multiple access (VNOMA) without channel state information at the transmitter (CSIT) is proposed. The novel idea is to construct multiple complex virtual channels by jointly adjusting the amplitudes and phases to maximize the minimum Euclidean distance (MED) among the superposed constellation points. The optimal solution is derived in the absence of CSIT. Considering practical communications with finite input constellations in which symbols are uniformly distributed, we resort to the sum constellation constrained capacity (CCC) to evaluate the performance. For MED criterion, the maximum likelihood (ML) decoder is expected at the receiver. To decrease the computational cost, we propose a reduced-complexity bitwise ML (RBML) decoder. Experimental results are presented to validate the superior of our proposed scheme.

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Section: Experiments Setup and Simulation Resultsmentioning

confidence: 81%

“…As we can see from Figure 2, our proposed scheme presents the same performance as 16-2D constellation. However, a closed-form solution is derived for our scheme which avoids the time-consuming iterative optimization as in [16].…”

Section: Experiments Setup and Simulation Resultsmentioning

confidence: 99%

Performance Improvement on Nonorthogonal Multiple Access without CSIT

Xia

Zhou

Meng

2020

Wireless Communications and Mobile Computing

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“…Multidimensional constellations can be projected onto a set of orthogonal 2-dimensional signal spaces (i.e., the I and Q channels) where each projection can be transmitted independently (e.g., [59]). We represent the projection of the jth complex element of x m onto two dimensions by x mj , 1 ≤ j ≤ d v .…”

Section: B Kpismentioning

confidence: 99%

Multidimensional Constellations for Uplink SCMA Systems—A Comparative Study

Vameghestahbanati

Marsland

Gohary

et al. 2019

IEEE Commun. Surv. Tutorials

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Sparse code multiple access (SCMA) is a class of non-orthogonal multiple access (NOMA) that is proposed to support uplink machine-type communication services. In an SCMA system, designing multidimensional constellation plays an important role in the performance of the system. Since the behavior of multidimensional constellations highly depends on the type of the channel, it is crucial to employ a constellation that is suitable for a certain application. In this paper, we first highlight and review the key performance indicators (KPIs) of multidimensional constellations that should be considered in their design process for various channel scenarios. We then provide a survey on the known multidimensional constellations in the context of SCMA systems with their design criteria. The performance of some of those constellations are evaluated for uncoded, high-rate, and low-rate LTE turbo-coded SCMA systems under different channel conditions through extensive simulations. All turbo-coded comparisons are performed for bit-interleaved coded modulation, with a concatenated detection and decoding scheme. Simulation results confirm that multidimensional constellations that satisfy KPIs of a certain channel scenario outperform others. Moreover, the bit error rate performance of uncoded systems, and the performance of the coded systems are coupled to their bit-labeling. The performance of the systems also remarkably depends on the behavior of the multi-user detector at different signal-to-noise ratio regions.Index Terms-Non-orthogonal multiple access (NOMA), Sparse code multiple access (SCMA), low density spreading (LDS), multidimensional constellation, SCMA codebook, fading channels, message passing algorithm (MPA), bit-interleaved coded modulation (BICM), key performance indicators (KPIs).

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“…Different optimization formulations can be found in [9]- [12] regarding various wireless and fiber-optical scenarios. However, it was shown in [13] that working with any choice of constellation may require more generalized error performance analysis for some pair of constellation and encoder in coded scenarios.…”

Section: Introductionmentioning

confidence: 99%

A Convolutionally Encoded OSTBC System with SNR-Adaptive Constellations for Low-Latency and Low-Complexity Communications

Ilter

Wichman

Hämäläinen

et al. 2018

2018 IEEE 19th International Workshop on Signal Processing Advances in Wireless Communications (SPAWC)

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The 5G and beyond wireless networks target novel use-cases with stringent requirements on physical layer parameters such as latency, which may necessitate design decisions with trade-offs. Choosing a channel coding scheme which gives the best error performance may not be the most appropriate choice in mission-critical machine-type communications which require very low latency. In such contexts, convolutional codes may be preferable due to their faster decoding and simplicity. Motivated by this observation, we introduce a convolutionally encoded OSTBC system with SNR-adaptive constellations for low-latency and low-complexity use-cases. Numerical results obtained for the versatile Nakagami-m channel demonstrate that the investigated scheme results in considerable gains in terms of error performance and decoding latency. 1

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Design of High-SNR Multidimensional Constellations for Orthogonal Transmission in a Nakagami- ${m}$ Fading Channel

Cited by 7 publications

References 45 publications

Performance Improvement on Nonorthogonal Multiple Access without CSIT

Performance Improvement on Nonorthogonal Multiple Access without CSIT

Multidimensional Constellations for Uplink SCMA Systems—A Comparative Study

A Convolutionally Encoded OSTBC System with SNR-Adaptive Constellations for Low-Latency and Low-Complexity Communications

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