A top-down SCMA codebook design scheme based on lattice theory

Yan, Haonan; Zhao, Hui; Lv, Zhaobiao; Yang, Haojun

doi:10.1109/pimrc.2016.7794680

Cited by 26 publications

(27 citation statements)

References 10 publications

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“…However, the rotation angles of user operators are not explicitly given. Although most of the existing codebook design methods for downlink provide codebooks with good performance [7]- [11], their performance degrades significantly in uplink. For uplink SCMA systems, fewer works exist in literature about the design of SCMA codebooks.…”

Section: A Related Workmentioning

confidence: 99%

Design of SCMA Codebooks Based on Golden Angle Modulation

Mheich

Wen

Xiao

et al. 2019

IEEE Trans. Veh. Technol.

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In this paper, we propose to use golden angle modulation (GAM) points to construct codebooks for uplink and downlink sparse code multiple access (SCMA) systems. We provide two categories of codebooks with one and two optimization parameters respectively. The advantages of the proposed design method are twofold: 1) the number of optimization variables is independent of codebook and system parameters; 2) it is simple to implement. In the downlink, we use GAM points to build a multidimensional mother constellation for SCMA codebooks, while in the uplink GAM points are directly mapped to user codebooks. The proposed codebooks exhibit good performance with low peak to average power ratio (PAPR) compared to the codebooks proposed in the literature based on constellation rotation and interleaving. Index Terms-Sparse code multiple access, codebook design, golden angle modulation, mapping, PAPR reduction. NOMA techniques can be classed under three categories: power-domain NOMA (PD-NOMA) [1], code-domain NOMA (CD-NOMA) [2], [3], [4] and a combination of PD-NOMA and CD-NOMA called power domain sparse code multiple access [5]. Low-density signature (LDS) [2], [3] is an efficient CD-NOMA that allows operating at overloaded conditions with performance close to single user case with affordable complexity. Due to the low-density property of signatures, only few users will use the same resource in order to reduce the interference and the data symbol for each user will be spread on a few number of resources. Like low-density parity-check coding, the low-density characteristic of LDS signatures allows to use the message passing algorithm (MPA) for multiuser

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Section: A Related Workmentioning

confidence: 99%

Design of SCMA Codebooks Based on Golden Angle Modulation

Mheich

Wen

Xiao

et al. 2019

IEEE Trans. Veh. Technol.

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“…And the SCMA codebook is calculated by interleaving users' codebooks on transmitting sources. Based on the direction, some effective methods in [10,[14][15][16][17][18] for the design of downlink SCMA systems codebook are proposed. Cai et al proposed a multi-dimensional codebook design based on constellation rotation and interleaving [14], which can be easily extended for any codebook and system parameters, such as number of sources, codebook size and codebook dimension.…”

Section: Introductionmentioning

confidence: 99%

A Novel SCMA Codebook Design Method Based on Low Error Probability Criteria

Yuan

Liu

Xiao

et al. 2021

2021 IEEE 6th International Conference on Signal and Image Processing (ICSIP)

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In this paper, we propose a method to construct codebooks for downlink sparse code multiple access (SCMA) systems. Different from the traditional methods in which codebooks are designed for each user, we allocate codebooks for each subchannel based on the most common modulation QAM. Then, low error probability criteria to measure the SCMA codebook performance in AWGN channel and Rayleigh fading channel are proposed. And simulated annealing algorithm is used to optimize the codebooks based on the criteria. Simulation results prove that the proposed codebooks exhibit good performance in both Rayleigh fading channel and AWGN channel, especially for high order SCMA systems.Keywords-Sparse code multiple access, codebook design, simulated annealing, AWGN channel, Rayleigh fading channel, highorder codebook.

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“…where D is a design criterion. A sub-optimal multi-stage optimization approach is deployed in [30,[51][52][53][54][55][56][57][58][59][60][61][62][63][64] for uplink SCMA systems that involves finding S * first and then X * . Moreover, when the system is fully overloaded, there is a unique solution for S * .…”

Section: Scma Multidimensional Constellation Designmentioning

confidence: 99%

“…[85] to obtain multidimensional constellations that are different for different users. Furthermore, the 4-point mother constellation that is proposed in [53] is similar to T4QAM, and is rotated according to [65] to differentiate the users. As mentioned earlier, the value of the 2-dimensional user-specific rotations becomes questionable in uplink scenarios.…”

Section: Tmqammentioning

confidence: 99%

“…In fact, it is a key feature that distinguishes SCMA from other NOMA techniques [38]. The design of multidimensional constellation has been studied for downlink SCMA systems in e.g., [42][43][44][45][46][47][48][49][50], and for uplink SCMA systems in e.g., [30,[51][52][53][54][55][56][57][58][59][60][61][62][63][64]. The objective of this work is to provide a thorough study on multidimensional constellations for uplink SCMA systems, and to highlight their design metrics under various channel scenarios.…”

Section: Introductionmentioning

confidence: 99%

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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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A top-down SCMA codebook design scheme based on lattice theory

Cited by 26 publications

References 10 publications

Design of SCMA Codebooks Based on Golden Angle Modulation

Design of SCMA Codebooks Based on Golden Angle Modulation

A Novel SCMA Codebook Design Method Based on Low Error Probability Criteria

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

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