Results 231 to 240 of about 51,024 (274)
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Fractional Sparse Code Multiple Access and Its Optimization
IEEE Wireless Communications Letters, 2018This letter proposes a fractional sparse code multiple access (FrSCMA) system in which each user directly maps a varying number of error-correction coded symbols onto the resource elements per channel use. The dynamic sparse mapping leads to a fractional spreading factor, often smaller than that in the existing multidimensional constellation (MDC ...
Ming Zhao, Dan Deng, Shengli Zhou
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Sparse Code Multiple Access Scheme Based on Variational Learning
IEEE Transactions on Communications, 2022 Sparse code multiple access (SCMA) technology has been widely studied thanks to its outstanding overload performance, which provides greater device access on limited time-frequency resources. We propose a variational learning based end-to-end SCMA network model termed as V-SCMA.
Quan Yuan +4 more
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On the Design of Near-Optimal Sparse Code Multiple Access Codebooks
IEEE Transactions on Communications, 2020Sparse code multiple access (SCMA) is one of the competitive non-orthogonal multiple access (NOMA) techniques for the next generation of communication systems. In this paper, a systematic construction procedure for the design of SCMA codebooks under various channel environments is proposed in order to achieve near-optimal designs, especially for cases ...
Yen-Ming Chen, Jian-Wei Chen
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Sparse Code Multiple Access With Time Spreading and Repetitive Transmissions
International Journal of Communication SystemsABSTRACTFor the next‐generation communication systems, to improve spectral efficiency and increase the data rate, new multiple access techniques have been investigated. Orthogonal multiple access techniques are widely used in traditional communication systems while nonorthogonal multiple access (NOMA), proposed in 5G, has been a promising technology ...
Oguz Ülgen +5 more
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SARA: Sparse Code Multiple Access-Applied Random Access for IoT Devices
IEEE Internet of Things Journal, 2018In this paper, we study a random access (RA) procedure to support the massive connectivity of the Internet of Things (IoT) devices, also known as the IoT connectivity. Compared with the previous RA procedures that have limitations to support the IoT connectivity due to the exponentially increased access delay, we develop an RA procedure by applying the
Seokjae Moon +2 more
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Low-Complexity Detector in Sparse Code Multiple Access Systems
IEEE Communications Letters, 2016One of the challenges in the design of sparse code multiple access systems is developing low-complexity detectors. To achieve this goal, we propose a novel low-complexity detector based on an edge selection approach, which remarkably reduces the computational complexity.
Yang Du, Binhong Dong, Zhi Chen
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Improved Message Passing Algorithms for Sparse Code Multiple Access
IEEE Transactions on Vehicular Technology, 2017Sparse code multiple access (SCMA) is one of the nonorthogonal multiple access techniques for the 5G system. SCMA can provide different levels of overloading to meet the diverse traffic connectivity requirements. However, its relatively high computational complexity of multiuser detection is still a significant concern for practical implementation ...
Jincheng Dai, Kai Niu, Chao Dong
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Sparse Autoencoder for Sparse Code Multiple Access
2021 International Conference on Artificial Intelligence in Information and Communication (ICAIIC), 2021In the forthcoming 5G technology, Sparse Code Multiple Access (SCMA) is the most promising scheme that aims at improving spectral efficiency further and providing massive connectivity. The challenge behind implementing SCMA scheme is: constructing optimized codebooks in order to obtain minimum BER while keeping the receiver complexity minimum.
Medini Singh +2 more
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Analyzing Uplink Grant-Free Sparse Code Multiple Access System in Massive IoT Networks
IEEE Internet of Things Journal, 2022 Grant-free sparse code multiple access (GF-SCMA) is considered to be a promising multiple access candidate for future wireless networks. In this article, we focus on characterizing the performance of uplink GF-SCMA schemes in a network with ubiquitous ...
Ke Lai, Jing Lei, Yansha Deng
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