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Enabling High Order SCMA Systems in Downlink Scenarios With a Serial Coding Scheme

Published on Jan 1, 2018in IEEE Access 4.10
· DOI :10.1109/access.2018.2842233
Yuxi Han2
Estimated H-index: 2
(USTC: University of Science and Technology of China),
Wuyang Zhou11
Estimated H-index: 11
(USTC: University of Science and Technology of China)
+ 1 AuthorsShengli Zhou52
Estimated H-index: 52
(UConn: University of Connecticut)
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Abstract
In the future fifth generation communication systems, sparse code multiple access (SCMA) shows strong competitiveness as a novel non-orthogonal multiple access (NOMA) technique. Attributing to multi-dimensional codebooks, the SCMA can obtain shaping gain and provide a better performance than some other NOMA schemes, such as pattern division multiple access, low-density signature (LDS), and so on. However, under higher user load, each orthogonal resource in high-order SCMA systems is occupied by more users and the constellations of these systems possess smaller Euclidean distances, both of which will degrade the link performance. The iterative algorithm employed in SCMA decoding, namely message passing algorithm, will also bring an exponential growth of computational complexity. In this paper, a scheme with serial codes for system order reduction in downlink scenarios, namely serial SCMA, is proposed to tackle these issues. Based on the idea of hierarchical coding, the processes of encoding and decoding in a high-order system are decomposed into several processes in low-order systems. Specific mapping modules are designed to recover the original user binary bits. Simulation results show that serial SCMA will substantially cut down the detection complexity and enjoy better link performance while maintaining sparser codebooks. Besides, it still inherits the advantages of original SCMA systems such as overloading and average aggregate energy efficiency over OMA and other NOMA schemes.
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Newest
Published on Jan 1, 2018in IEEE Access 4.10
Mohammad Moltafet2
Estimated H-index: 2
(TMU: Tarbiat Modares University),
Nader Mokari9
Estimated H-index: 9
(TMU: Tarbiat Modares University)
+ 2 AuthorsHossein Pishro-Nik17
Estimated H-index: 17
(UMass: University of Massachusetts Amherst)
In this paper, a new approach for multiple access in the fifth generation (5G) of cellular networks called power domain sparse code multiple access (PSMA) is proposed. In PSMA, we adopt both the power domain and the code domain to transmit multiple users’ signals over a subcarrier simultaneously. In such a model, the same sparse code multiple-access (SCMA) codebook can be used by multiple users, where, for these users, the power domain non-orthogonal multiple access (PD-NOMA) technique is used t...
Published on Dec 1, 2017in IEEE Communications Letters 3.46
Monirosharieh Vameghestahbanati1
Estimated H-index: 1
(Carleton University),
Ebrahim E. Bedeer-Mohamed7
Estimated H-index: 7
(Ulster University)
+ 2 AuthorsHalim Yanikomeroglu35
Estimated H-index: 35
(Carleton University)
In this letter, we propose a reduced-complexity optimal modified sphere decoding (MSD) detection scheme for sparse code multiple access (SCMA). As SCMA systems are characterized by a number of resource elements that are less than the number of the supported users, the channel matrix is rank-deficient, and SD cannot be directly applied. Inspired by the Tikhonov regularization, we formulate a new full-rank detection problem that it is equivalent to the original rank-deficient detection problem for...
Published on Aug 1, 2017in IEEE Transactions on Communications 5.69
Li Li10
Estimated H-index: 10
(Southwest Jiaotong University),
Zheng Ma9
Estimated H-index: 9
(Southwest Jiaotong University)
+ 2 AuthorsLajos Hanzo65
Estimated H-index: 65
(University of Southampton)
For the sake of supporting massive connectivity in the future 5G networks, non-orthogonal multiple access (NOMA) techniques are advocated. As a promising NOMA technique, in recent years sparse code multiple access (SCMA) has attracted substantial attention. However, there is a paucity of studies on the theoretical analysis of its error-freely achievable data rate, especially, in the downlink context. Hence, we derive the cutoff rate of SCMA in downlink broadcast channels, which indicates the low...
Published on Feb 1, 2017in IEEE Transactions on Communications 5.69
Fan Wei1
Estimated H-index: 1
(SJTU: Shanghai Jiao Tong University),
Wen Chen50
Estimated H-index: 50
(SJTU: Shanghai Jiao Tong University)
Sparse code multiple access (SCMA) is one of the most promising methods among all the non-orthogonal multiple access techniques in the future 5G communication. Compared with some other non-orthogonal multiple access techniques, such as low density signature, SCMA can achieve better performance due to the shaping gain of the SCMA code words. However, despite the sparsity of the code words, the decoding complexity of the current message passing algorithm utilized by SCMA is still prohibitively hig...
Published on Jan 1, 2017in IEEE Communications Letters 3.46
Ming Zhao8
Estimated H-index: 8
(USTC: University of Science and Technology of China),
Shengli Zhou52
Estimated H-index: 52
(UConn: University of Connecticut)
+ 1 AuthorsZhuJinkang8
Estimated H-index: 8
(USTC: University of Science and Technology of China)
Sparse coded multiple access (SCMA) has received considerable attention recently as a candidate multiple access scheme for 5G cellular systems. This letter proposes an improved uplink SCMA scheme where instead of the multi-dimensional constellation (MDC) mapping and a fixed number of nonzero elements per sparse codeword, a varying number of coded symbols from each user are directly mapped onto the resource elements. We show that the proposed SCMA scheme outperforms the MDC-SCMA scheme in terms o...
Published on Jan 1, 2017in IEEE Transactions on Vehicular Technology 5.34
Mohammad Moltafet2
Estimated H-index: 2
(TMU: Tarbiat Modares University),
Nader Mokari Yamchi3
Estimated H-index: 3
(TMU: Tarbiat Modares University)
+ 1 AuthorsPaeiz Azmi12
Estimated H-index: 12
(TMU: Tarbiat Modares University)
In this paper, the performance and system complexity of the candidate multiple access (MA) techniques for the next generation of cellular systems, namely, power domain nonorthogonal multiple access (PD-NOMA) and sparse code multiple access (SCMA), are investigated. To this end, for each MA technique, a resource allocation problem considering heterogeneous cellular networks is formulated. We apply successive convex approximation method to each problem and obtain their solutions. Simulation result...
Published on Jul 1, 2016 in ICC (International Conference on Communications)
Ziyang Li1
Estimated H-index: 1
(SJTU: Shanghai Jiao Tong University),
Wen Chen50
Estimated H-index: 50
(SJTU: Shanghai Jiao Tong University)
+ 3 AuthorsYan Chen22
Estimated H-index: 22
(Huawei)
Sparse Code Multiple Access (SCMA) is a non-orthogonal multi-dimensional spreading technique based on layered codebooks. In SCMA, incoming bits are directly mapped to multi-dimensional codewords of pre-defined codebooks. In comparison to simple repetition of QAM symbols in Low Density Signature (LDS), shaping gain of the multi-dimensional constellation is the main advantage of SCMA for performance improvement. Similar to LDS, SCMA can take the advantage of a near optimal Message Passing Algorith...
Published on May 1, 2016 in VTC (Vehicular Technology Conference)
Jinchen Bao4
Estimated H-index: 4
(Southwest Jiaotong University),
Zheng Ma9
Estimated H-index: 9
(Southwest Jiaotong University)
+ 2 AuthorsDageng Chen6
Estimated H-index: 6
(Huawei)
In this paper, we investigate the application of spherical codes in a sparse code multiple access (SCMA) system. We use spherical codes to build multidimensional mother constellations for SCMA codebooks, to lower peak to average power ratio (PAPR) as well as to improve the overall spectrum efficiency. Furthermore, we introduce four approaches to construct good spherical codes. These codes are easy and have large coding gains. We make extensions to some of these spherical codes such that they are...
Published on May 1, 2016 in VTC (Vehicular Technology Conference)
Donghong Cai1
Estimated H-index: 1
(Southwest Jiaotong University),
Pingzhi Fan35
Estimated H-index: 35
(Southwest Jiaotong University)
+ 2 AuthorsDageng Chen6
Estimated H-index: 6
(Huawei)
Sparse code multiple access (SCMA) is a new non- orthogonal multiple access scheme, which effectively exploits the shaping gain of multi-dimensional codebook. In this paper, a multi-dimensional SCMA (MD-SCMA) codebook design based on constellation rotation and interleaving method is proposed for downlink SCMA systems. In particular, the first dimension of mother constellation is constructed by subset of lattice \mathbf{Z}^2 Then the other dimensions are obtained by rotating the first dimensio...
Published on May 1, 2016in IEEE Signal Processing Letters 3.27
Jienan Chen6
Estimated H-index: 6
(University of Electronic Science and Technology of China),
Zhenbing Zhang2
Estimated H-index: 2
(University of Electronic Science and Technology of China)
+ 2 AuthorsGerald E. Sobelman19
Estimated H-index: 19
(UMN: University of Minnesota)
Nonorthogonal multiple access technology has been proposed for use in 5G communications systems. In particular, the sparse code multiple access (SCMA) scheme is believed to be one of the most promising techniques among the various nonorthogonal approaches that have been investigated. In this letter, we focus on reducing the complexity of SCMA decoding and we propose a Monte Carlo Markov Chain (MCMC) based SCMA decoder. Benefiting from the linearly increasing complexity of the MCMC method, the pr...
Cited By1
Newest
Mohammad Moltafet2
Estimated H-index: 2
,
Saeedeh Parsaeefard12
Estimated H-index: 12
+ -3 AuthorsNader Mokari9
Estimated H-index: 9
(TMU: Tarbiat Modares University)
In this paper, by considering multiple slices, a downlink transmission of a sparse code multiple access (SCMA) based cloud-radio access network (C-RAN) is investigated. In this regard, by supposing multiple input and single output (MISO) transmission technology, a novel robust radio resource allocation is proposed where considering uncertain channel state information (CSI), the worst case approach is applied. The main goal of the proposed radio resource allocation is to, maximize the system sum ...