A capacity-based codebook design method for sparse code multiple access systems

Zhang, Shutian; Xiao, Kexin; Xiao, Baicen; Chen, Zhiyong; Xia, Bin; Chen, Dageng; Ma, Shaodan

doi:10.1109/wcsp.2016.7752620

Cited by 67 publications

(55 citation statements)

References 13 publications

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“…In addition, for the 4 × 6 SCMA scheme, the codebooks in [15] are used, whose design details are given in [16]. Note that this SCMA codebook design aims for maximizing the sum rate based on the rotation of pulse-amplitude modulation (PAM) constellations.…”

Section: Performance Evaluationmentioning

confidence: 99%

Polar-Coded Non-Orthogonal Multiple Access

Dai

Niu

et al. 2018

IEEE Trans. Signal Process.

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Abstract-Non-orthogonal multiple access (NOMA) is one of the key techniques to address the high spectral efficiency and massive connectivity requirements for the fifth generation (5G) wireless system. To efficiently realize NOMA, we propose a joint design framework combining the polar coding and the NOMA transmission, which deeply mines the generalized polarization effect among the users. In this polar coded NOMA (PC-NOMA) framework, the original NOMA channel is decomposed into multiple bit polarized channels by using a three-stage channel transform, that is, user→signal→bit partitions. Specifically, for the first-stage channel transform, we design two schemes, namely sequential user partition (SUP) and parallel user partition (PUP). For the SUP, a joint successive cancellation detecting and decoding scheme is developed, and a search algorithm is proposed to schedule the NOMA detecting order which improves the system performance by enhanced polarization among the user synthesized channels. The "worst-goes-first" idea is employed in the scheduling strategy, and its theoretic performance is analyzed by using the polarization principle. For the PUP, a corresponding parallel detecting scheme is exploited to reduce the latency. The block error ratio performances over the additive white Gaussian noise channel and the Rayleigh fading channel indicate that the proposed PC-NOMA obviously outperforms the state-of-the-art turbo coded NOMA scheme due to the advantages of joint design between the polar coding and NOMA.

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Section: Performance Evaluationmentioning

confidence: 99%

Polar-Coded Non-Orthogonal Multiple Access

Dai

Niu

et al. 2018

IEEE Trans. Signal Process.

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“…The matrix F denotes the channel matrix in AWGN scenario. The existing codebook designs in [10,11,17,18] are mainly based on F in (1). However, in the wireless communication, the channel response amplitudes and phases of users are usually different from each other.…”

Section: Typical Scma Modelmentioning

confidence: 99%

“…Furthermore, in the recent paper [15], SCMA detection can be seen as a specific tree search problem and sphere decoding algorithm shows much lower complexity with negligible performance loss. Inspired by transmit signal optimization in two-user multiple access channels [16], SCMA codebook design is mainly focused on phase rotation optimization in [17,18]. In addition, the product distance and cutoff-rate are introduced to optimize SCMA codebook in [19] and [20], respectively.…”

Section: Introductionmentioning

confidence: 99%

An Efficient SCMA Codebook Optimization Algorithm Based on Mutual Information Maximization

Dong

Gao

Niu

et al. 2018

Wireless Communications and Mobile Computing

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An efficient codebook optimization algorithm is proposed to maximize mutual information in sparse code multiple access (SCMA). At first, SCMA signal model is given according to superposition modulation structure, in which the channel matrix is column-extended. The superposition model can well describe the relationship between the codebook matrix and received signal. Based on the above model, an iterative codebook optimization algorithm is proposed to maximize mutual information between discrete input and continuous output. This algorithm can efficiently adapt to multiuser channels with arbitrary channel coefficients. The simulation results show that the proposed algorithm has good performance in both AWGN and non-AWGN channels. In addition, message passing algorithm (MPA) works well with the codebook optimized according to the proposed algorithm.

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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%

“…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%

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 capacity-based codebook design method for sparse code multiple access systems

Cited by 67 publications

References 13 publications

Polar-Coded Non-Orthogonal Multiple Access

Polar-Coded Non-Orthogonal Multiple Access

An Efficient SCMA Codebook Optimization Algorithm Based on Mutual Information Maximization

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

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