A Low-Complexity Codebook Design Scheme for SCMA Systems Over an AWGN Channel

Zheng, Yu; Xin, Jiantao; Wang, Hui; Zhang, Shengli; Qiao, Yongjie

doi:10.1109/tvt.2022.3175540

Cited by 10 publications

(8 citation statements)

References 33 publications

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“…where a 1 , a 2 , a 3 , a In this paper, a separable user codebook structure is adopted, where each non-zero element of a K-dimensional codeword corresponds to one user bit, respectively [20]. This leads to a lower number of distinct codewords in each one-dimensional codebook, which reduces the total number of possible values for multi-user superimposed codewords per dimension and increases the MED between superimposed codewords.…”

Section: Codebook Structure Designmentioning

confidence: 99%

A Superimposed Codebook Design for Downlink Sparse Code Multiple Access Visible Light Communication System

Dong,

Wang,

et al. 2024

Photonics

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The capacity performance of visible light communication (VLC) systems can be improved by using sparse code multiple access (SCMA). Since SCMA is a codebook-based multiple access scheme, the design of the codebook is crucial. SCMA codebook performance is severely affected by shot noise. Although several codebook design metrics have been proposed to compensate for the constellation distortion caused by shot noise, the improvement in performance is limited. In order to solve this problem, we use a separable codebook design structure to derive the analytical expression of the symbol error rate (SER) for the SCMA-VLC system under shot noise. According to the SER expression, we formulate an optimization problem and obtain a multi-user superimposed codebook to achieve a minimum SER for the SCMA-VLC system. The simulation results show that the proposed codebook significantly improves the performance of the SCMA-VLC system, especially in the case of high shot noise.

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Section: Codebook Structure Designmentioning

confidence: 99%

A Superimposed Codebook Design for Downlink Sparse Code Multiple Access Visible Light Communication System

Dong,

Wang,

et al. 2024

Photonics

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“…On the aspect of codebook design, following the initial codebook proposed by Nikopour et al [26], extensive research has been conducted to construct the SCMA codebook [17]- [19], [23], [25], [27]- [31]. Among which, the mother codebook based method has been widely adopted in some approaches [17], [23], [27], [32].…”

Section: A Literature and Motivationmentioning

confidence: 99%

“…While in the procedure generating the constellation group, the optimization of the rotation degree is more complicated than traditional 2D codebooks since 3D rotation matrix introduces more degrees. (31) Meanwhile, the joint optimization (20) in 3D SCMA system can be further written as…”

Section: Construction Of the 3d Scma Codebooksmentioning

confidence: 99%

A Novel Scheme for the Construction of the SCMA Codebook

Lei

Cheng

et al. 2022

IEEE Access

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As a code-domain non-orthogonal multiple access technique, sparse code multiple access (SCMA) is considered as a promising technique for future wireless Internet of Things (IoT) networks. The minimum Euclidean distance (MED) and minimum product distance (MPD) have been highlighted as the key performance indicators of the codebook in additive gaussian white noise (AWGN) and downlink Rayleigh channels respectively. In this paper, based on the mother codebook, a novel codebook design scheme is proposed to achieve better error performance in both AWGN and downlink Rayleigh channels. The problem of constructing the mother codebook is considered as the quadratic assignment problem (QAP), where the Tabu searching algorithm is employed to reduce the complexity of searching for the best permutation result. Then, the rotation matrix is adopted to find the best degrees for the generation of the constellation group, and two algorithms are proposed to assign the obtained constellation in factor graph matrix. Taking the degree optimization and the constellation assignments into joint consideration, an improved unified optimization is further explored to maximize the MED of each user. Besides, a novel polarized modulation scheme is proposed, which places the symbols in the three dimensional (3D) stokes parameters to improve the performance of the system. Finally, simulation results are provided to show the performance of the proposed codebooks, and the comparisons of symbol error performance (SER) in different codebooks are also discussed in detail.INDEX TERMS Sparse code multiple access (SCMA), codebook design, minimum Euclidean distance, minimum product distance, three dimensional SCMA codebooks

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“…More recently, a novel algorithm based on alternating maximization with the exact penalty was proposed in [ 14 ] for the minimum Euclidean distance (MED) maximization problem. Zheng et al proposed a simplified SCMA codebook with a separable structure in [ 15 ], which simplifies MED maximization when implementing a low-complexity detector. Based on the mother codebook, Lei et al proposed a novel codebook design scheme to achieve better error performance and further explored an improved unified optimization to maximize the MED of each user in [ 16 ].…”

Section: Introductionmentioning

confidence: 99%

Windowed Joint Detection and Decoding with IR-HARQ for Asynchronous SCMA Systems

Guan

Zhu

Bai

2023

Entropy

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To improve the decoding performance of asynchronous sparse code multiple access (SCMA) systems over additive white Gaussian noise (AWGN) channels, this paper proposes a novel windowed joint detection and decoding algorithm for a rate-compatible (RC), LDPC code-based, incremental redundancy (IR) hybrid automatic repeat quest (HARQ) scheme. Since incremental decoding can exchange information iteratively with the detections made at previous consecutive time units, we propose a windowed joint detection and decoding algorithm. The extrinsic information exchanging process is performed between the decoders and the previous w detectors at different consecutive time units. Simulation results show that the sliding-window IR-HARQ scheme for the SCMA system outperforms the original IR-HARQ scheme with a joint detection and decoding algorithm. The throughput of the SCMA system with the proposed IR-HARQ scheme is also improved.

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A Low-Complexity Codebook Design Scheme for SCMA Systems Over an AWGN Channel

Cited by 10 publications

References 33 publications

A Superimposed Codebook Design for Downlink Sparse Code Multiple Access Visible Light Communication System

A Superimposed Codebook Design for Downlink Sparse Code Multiple Access Visible Light Communication System

A Novel Scheme for the Construction of the SCMA Codebook

Windowed Joint Detection and Decoding with IR-HARQ for Asynchronous SCMA Systems

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