Sparse Code Multiple Access (SCMA)

Ma, Zheng; Bao, Jianrong

doi:10.1007/978-3-319-92090-0_12

Cited by 17 publications

(4 citation statements)

References 24 publications

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“…In [36], an overview of multi-dimensional constellations as well as their applications in CB design for uplink SCMA systems has been presented. A book chapter is reported in [37], where the basic principles of SCMA are briefly covered along with CB designing and MUD. An introduction to SCMA was given in [38], covering an overview survey of the CB design, detector designs, and some other aspects like resource allocation, practical implementations.…”

Section: B Motivations and Contributionsmentioning

confidence: 99%

A Tutorial on Decoding Techniques of Sparse Code Multiple Access

et al. 2022

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Sparse Code Multiple Access (SCMA) is a disruptive code-domain non-orthogonal multiple access (NOMA) scheme to enable future massive machine-type communication networks. As an evolved variant of code division multiple access (CDMA), multiple users in SCMA are separated by assigning distinctive sparse codebooks (CBs). Efficient multiuser detection is carried out at the receiver by employing the message passing algorithm (MPA) that exploits the sparsity of CBs to achieve error performance approaching to that of the maximum likelihood receiver. In spite of numerous research efforts in recent years, a comprehensive one-stop tutorial of SCMA covering the background, the basic principles, and new advances, is still missing, to the best of our knowledge. To fill this gap and to stimulate more forthcoming research, we provide a holistic introduction to the principles of SCMA encoding, CB design, and MPA based decoding in a self-contained manner. As an ambitious paper aiming to push the limits of SCMA, we present a survey of advanced decoding techniques with brief algorithmic descriptions as well as several promising directions.

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Section: B Motivations and Contributionsmentioning

confidence: 99%

A Tutorial on Decoding Techniques of Sparse Code Multiple Access

et al. 2022

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“…In Reference 14, a low‐complexity iterative uplink SCMA receiver is proposed based on the Expectation Propagation Algorithm. The contents of the codebook design, the structure of the codewords, factor graph, optimal MUD, MPA Detection, and other detectors in SCMA are expressed in Reference 34. It has also been concluded that multi‐user codebook plays an essential role in improving system performance 34 …”

Section: Introductionmentioning

confidence: 99%

Resource allocation in sparse code multiple access‐based systems for cloud‐radio access network in 5G networks

Zavleh

Bakhshi

2020

Trans Emerging Tel Tech

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In this paper, downlink joint user association, codebook assignment and power allocation for a Sparse Code Multiple Access (SCMA)‐based in Cloud Radio Access Network (C‐RAN) are investigated. The main aim of this paper is to accomplish a resource allocation to achieve the maximum total sum rate subject to SCMA limitation, total available power in Radio Remote Head (RRH), fronthaul constraint, users association, user power constraint, and Quality of Service requirements for each user with low complexity. To solve the recommended problem an iterative algorithm considering Successive Convex Approximation is utilized. The main problem is separated into two subproblems of joint user association and codebook assignment and power allocation. By defining a new binary variable for user association and codebook assignment and a new constraint for the user association, the joint user association and codebook assignment subproblem becomes an Integer Linear Programming. Then user association and codebook assignment subproblem solved with the help of the CVX toolbox and MOSEK solver. Furthermore, to solve the power allocation subproblem, Successive Convex Approximation with Low Complexity is applied. Then the power allocation subproblem solved by subgradient method for the Lagrange dual problem. In the simulation results, the effectiveness of the recommended optimization algorithm and resource allocation method are shown and compared to Non‐Orthogonal Multiple Access and Orthogonal Frequency Division Multiple Access.

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“…In this section, numerical results are provided to compare the performance of the proposed ISD scheme with Log-MPA (e.g., [119]) and ML for the following scenarios 3). We also use a single antenna at the transmitter of all users and at the receiver.…”

Section: Performance Evaluationmentioning

confidence: 99%

“…In practical implementations, the exponential operations in (C2) causes large dynamic ranges, which may result in a high storage burden [119]. As such, MPA in the logarithmic domain (Log-MPA) is used instead.…”

Section: Users Resourcesmentioning

confidence: 99%

Designing Multidimensional Constellations and Efficient Detection Schemes for Sparse Code Multiple Access (SCMA) Systems

Vameghestahbanati¹

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Sparse code multiple access (SCMA) is a class of non-orthogonal multiple access that is proposed to support uplink machine-type communication services. In this thesis, we investigate the design of SCMA systems from two main aspects: multidimensional constellations (MdCs) and efficient detection schemes. In an SCMA system, designing MdCs plays an important role in the system performance. 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 the first part of this thesis, we highlight and review the key performance indicators (KPIs) of MdCs that should be considered in their design process for various channel scenarios. We also provide a survey on the known MdCs in the context of SCMA systems with their design criteria. The performance of some of those constellations are evaluated for uncoded and LTE turbo-coded SCMA systems under different channel conditions through extensive simulations. We then investigate the effect of the 5G low density parity check (LDPC) codes on determining KPIs in designing MdCs under various channel scenarios. Since the optimal maximum likelihood (ML) receiver for SCMA is too complex in most applications, one highly popular detection technique is the message passing algorithm (MPA), which exploits the sparsity structure of SCMA. MPA is a near-optimal technique, where its performance improves with increasing the signal-to-noise-ratio (SNR) and the number of iterations. We design novel SCMA SNR-adaptive MdCs which result in substantial performance gains (as much as 2 dB) in comparison to the best known SCMA MdCs in the literature, especially in low-to-medium SNR regions when the number of MPA iterations has to be low, and in the presence of 5G-compliant LDPC codes. Sphere decoding (SD) based detection schemes for SCMA have recently received attention due to their promising features. However, the existing SD-based schemes can only be applied to systems with constellations that possess a certain structure. In the second part of the thesis, we propose an SD-based detection scheme, namely improved SD (ISD), for SCMA that achieves the optimal ML detector for any arbitrary regular or irregular constellations. I would also like to mention the government of Ontario in acknowledgment of the Ontario Trillium scholarship which pledged a wide support to my Ph.D., Huawei Technologies research and development team, specially Dr.

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Sparse Code Multiple Access (SCMA)

Cited by 17 publications

References 24 publications

A Tutorial on Decoding Techniques of Sparse Code Multiple Access

A Tutorial on Decoding Techniques of Sparse Code Multiple Access

Resource allocation in sparse code multiple access‐based systems for cloud‐radio access network in 5G networks

Designing Multidimensional Constellations and Efficient Detection Schemes for Sparse Code Multiple Access (SCMA) Systems

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