A Novel SD-Based Detection for Generalized SCMA Constellations

Vameghestahbanati, Monirosharieh; Marsland, Ian; Gohary, Ramy H.; Yanıkömeroğlu, Halim

doi:10.1109/tvt.2019.2932907

Cited by 13 publications

(12 citation statements)

References 20 publications

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“…In this section we provide a comprehensive description of SD-based SCMA detector state-of-the-art, which are SD-SCMA [22] and GSD-SCMA [23]. We not only elaborate on the state-of-the-art by illustrating with flowcharts and detailed pseudo-code algorithms, but also enhance the original scheme by adopting SQRD.…”

Section: State-of-the-art Sd-based Scma Detectorsmentioning

confidence: 99%

“…Limited by the shape of the channel matrix, SD-SCMA constrains the transmitted codewords to have constant modulus. To overcome this constraint, authors in [23] propose the generalized SD for SCMA (GSD-SCMA) which splits the MUD into two parts. As GSD-SCMA performs a brute-force search on partial transmitted symbols, its computational complexity may surge when the codebook size or overloading factor is large.…”

Section: Introductionmentioning

confidence: 99%

“…The system model is expressed to be linear which is applicable to all types of SCMA codebooks. • Based on [22], [23], we present the SD-SCMA and GSD-SCMA detectors in a comprehensive way. As a novel contribution, we leverage the sorted QR decomposition (SQRD) [24] and Schnorr-Euchner (SE) enumeration [25] in those detectors to further enhance the decoding efficiency and accelerate the tree search speed.…”

Section: Introductionmentioning

confidence: 99%

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A Simplified Sphere Decoding-Based Detector for Generalized SCMA Codebooks

Ruyet

Silva³

et al. 2022

IEEE Access

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Sparse code multiple access (SCMA) is one of the promising schemes to meet high connectivity and spectral efficiency in the future wireless networks. The iterative detectors, for example message passing algorithm (MPA), can provide near optimal multiuser detection (MUD) performance but becomes infeasible when the codebook size is large or the overloading factor is high. Recently, sphere decoding (SD) has been considered in the MUD of SCMA by rewriting the generalized transmission into a linear system. In this work, we first review the state-of-the-art SD-based detectors for SCMA: sphere decoding for SCMA (SD-SCMA) and generalized SD-SCMA (GSD-SCMA). We not only explain the state-of-the-art in a comprehensive way, but also exploit the sorted QR decomposition and Schnorr-Euchner enumeration to accelerate the tree search. Although GSD-SCMA overcomes the codebook constraint of SD-SCMA, its computational complexity is extremely sensitive to the overloading factor. To satisfy the tradeoff between complexity and MUD performance, we propose two pruning algorithms, PRUN1 and PRUN2, and introduce the simplified GSD-SCMA (SGSD-SCMA). In the paper, error probabilities of the proposed pruning algorithms are derived. Simulation results show that the proposed detector outperforms the iterative detectors and SD-based state-of-the-art when the overloading factor is moderate and the codebook size is large.

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Section: State-of-the-art Sd-based Scma Detectorsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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A Simplified Sphere Decoding-Based Detector for Generalized SCMA Codebooks

Ruyet

Silva³

et al. 2022

IEEE Access

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“…One way to reduce the complexity of the SCMA maximum likelihood detector is to restrict the space of codeword research to a hyper-sphere centered around the received signal vector as depicted in Figure 19, this technique is called sphere decoding (SD) [142]. Several research works proposed how to apply SD to SCMA detector [81], [96], [143]- [151] in the aim of reducing the complexity while still providing good performances.…”

Section: Sphere Decodingmentioning

confidence: 99%

“…MSTS not only has lower computational complexity than MPA based detectors but also keeps its performance level close to that of MPA. One drawback of the aforementioned methods is that they cannot support some of the non-constant modulus constellations, that is why a a new improved SD (ISD) method that can support any constellation topology was introduced in [151].…”

Section: Sphere Decodingmentioning

confidence: 99%

Sparse Code Multiple Access: Potentials and Challenges

Rebhi

Hassan

Raoof

et al. 2021

IEEE Open J. Commun. Soc.

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The massive connectivity is among other unprecedented requirements which are expected to be satisfied in order to follow the perpetual increase of connected devices in the era of internet of things. In contrast to the family of conventional orthogonal multiple access schemes, the key distinguishing feature of non-orthogonal multiple access (NOMA) is its capacity to support the massive connectivity. Sparse code multiple access (SCMA) is one of the powerful schemes of code-domain NOMA (CD-NOMA) and is among the promising candidates of multiple access techniques to be employed in future generations of wireless communication systems thanks to the sparsity pattern of its codebooks. This technique has been actively investigated in recent years. In this paper, we provide a comprehensive survey of the state-of-the-art of SCMA. First, we will pinpoint SCMA place in the NOMA landscape including power-domain NOMA and CD-NOMA with the aim of justifying why SCMA is prominent. Then, its system architecture is highlighted and its basic principles are presented, afterwards a review of exiting codebook designs and available SCMA detectors is provided, before showing how resources are expected to be assigned, and how SCMA can be combined with other existing and emerging technologies. Finally, we present a range of future research trends and challenging open issues that should be addressed to optimize SCMA performance.

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