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On Capacity-Based codebook Design and Advanced Decoding for sparse code multiple access Systems

IEEE TRANSACTIONS ON WIRELESS COMMUNICATIONS 2018年第6期17卷 3834-3849页

作者： Xiao, Kexin Xia, Bin Chen, Zhiyong Xiao, Baicen Chen, Dageng Ma, Shaodan Shanghai Jiao Tong Univ Dept Elect Engn Inst Wireless Commun Technol Shanghai Inst Adv Commun & Data Sci Shanghai 200240 Peoples R China Shanghai Jiao Tong Univ Dept Elect Engn Inst Wireless Commun Technol Shanghai 200240 Peoples R China Univ Washington Dept Elect Engn Seattle WA 98105 USA Shanghai Jiao Tong Univ Cooperat Medianent Innovat Ctr Shanghai 200240 Peoples R China Shanghai Key Lab Digital Media Proc & Transmiss Shanghai 200240 Peoples R China Huawei Technol Co Ltd Commun Technol Lab Shanghai 201206 Peoples R China Univ Macau Dept Elect & Comp Engn Macau 999078 Peoples R China

sparse code multiple access (SCMA) is a promising non-orthogonal air-interface technology for its ability to support massive connections. In this paper, we design the multiuser codebook and the advanced decoding from the perspective of the theoretical capacity and the system feasibility. First, different from the lattice-based constellation in point-to-point channels, we propose a novel codebook for maximizing the constellation constrained capacity. We optimize a series of 1-D superimposed constellations to construct multi-dimensional codewords. An effective dimensional permutation switching algorithm is proposed to further obtain the capacity gain. Consequently, it shows that the performance of the proposed codebook approaches the Shannon limit and achieves significant gains over the other existing ones. Furthermore, we provide a symbol-based extrinsic information transfer tool to analyze the convergence of SCMA iterative detection, where the complex codewords are considered in modeling the a priori probabilities instead of assuming the binary inputs in previous literature. Finally, to approach the capacity, we develop a low-density parity-check code-based SCMA receiver. Most importantly, by utilizing the EXIT charts, we propose an iterative joint detection and decoding scheme with only partial inner iterations, which exhibits significant performance gain over the traditional one with separate detection and decoding.

关键词： sparse code multiple access multi-dimensional codebook converge analysis iterative decoding

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Semi-granted sparse code multiple access (SCMA) for 5G Networks (Invited Paper) 3rd

Semi-granted Sparse Code Multiple Access (SCMA) for 5G Netwo...

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3rd European-Alliance-for-Innovation (EAI) International Conference on IoT as a Service (IoTaaS)

作者： Yang, Mao Li, Bo Bai, Zhicheng Zuo, Xiaoya Yan, Zhongjiang Liang, Yusheng Northwestern Polytech Univ Sch Elect & Informat Xian Peoples R China

ISBN: (纸本)9783030004101;9783030004095

sparse code multiple access (SCMA) is a promising non-orthogonal multiple access technology for 5G radio access networks. It improves the connectivity and capacity. However, the two multiple access methods of SCMA: granted and grant-free cannot dynamically match the real-time demands since the resources allocated for the granted method and grant-free method are clearly separated with each other. This further deteriorates the system performance. This article proposes a semi-granted SCMA method, by enabling the granted demands and grantfree demands to share the same resources. Simulation results confirm that semi-granted SCMA matches the dynamically fluent demands and significantly improve the throughput of SCMA 5G system.

关键词： sparse code multiple access SCMA Non-orthogonal multiple access multiple access Grant-free 5G

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T-SCMA: Time Domain sparse code multiple access for Narrow Band Internet of Things (NB-IoT) (Invited Paper) 3rd

T-SCMA: Time Domain Sparse Code Multiple Access for Narrow B...

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3rd European-Alliance-for-Innovation (EAI) International Conference on IoT as a Service (IoTaaS)

作者： Yan, Zhenzhen Li, Bo Yang, Mao Yan, Zhongjiang Bai, Zhicheng Northwestern Polytech Univ Sch Elect & Informat Xian Peoples R China

ISBN: (纸本)9783030004101;9783030004095

Nowadays the development of internet of things (IoT) has become the next major growth point of wireless communication. And narrow band has become a new trend in the development of IoT. Achieving massive connectivity and ever-increasing network capacity has become an important subject of our research. We find that sparse code multiple access (SCMA), a type of non-orthogonal multiple access, is supposed to meet these needs, but it can hardly apply to NB-IoT because narrow band does not have the ability of spread spectrum. On this basis, we introduce SCMA into time domain, named T-SCMA, for NB-IoT. By multiplexing SCMA in the time domain and defining a MAC frame structure, we can significantly improve both connectivity and network capacity, ultimately obtain a much higher throughput property gain over time division multiple address (TDMA).

关键词： Internet of Things sparse code multiple access NB-IoT Connectivity Network capacity

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A Tight Lower Bound for the Symbol Error Performance of the Uplink sparse code multiple access

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IEEE WIRELESS COMMUNICATIONS LETTERS 2017年第2期6卷 190-193页

作者： Cai, Donghong Fan, Pingzhi Mathiopoulos, P. Takis Southwest Jiaotong Univ Inst Mobile Commun Chengdu 610031 Peoples R China Univ Athens Dept Informat & Telecommun Athens 15784 Greece

We derive a tight lower bound for symbol error rate (SER) performance of the sparse code multiple access (SCMA) uplink operated over Rayleigh fading channels. In particular, based on the working principle of message passing algorithm receiver and the special structure of the sparse binary matrix, which is used to control the collisions of SCMA system, the system can be simplified to a single user single input multiple output (SU-SIMO) system employing maximal ratio combining (MRC) reception. In this way, the average SER lower bound of SCMA is obtained by calculating the average SER of SU-SIMO system employing MRC reception. Our results show that the derived lower bound is not only an efficient means of analyzing the SER performance, but also is tight, especially in the high signal-to-noise ratio regime.

关键词： sparse code multiple access multiple access interference symbol error rate

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FH-SCMA: Frequency-hopping based sparse code multiple access for Next Generation Internet of Things

FH-SCMA: Frequency-hopping based Sparse Code Multiple Access...

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IEEE Wireless Communications and Networking Conference (WCNC)

作者： Bai, Zhicheng Li, Bo Yang, Mao Yan, Zhongjiang Zuo, Xiaoya Zhang, Yongping Northwestern Polytech Univ Sch Elect & Informat Xian Peoples R China

ISBN: (纸本)9781509041831

The next generation Internet of Things (IoT) is expected to support extremely diverse applications and terminals, which requires the massive connectivity. Unfortunately, current mobile communication systems with orthogonal multiple access technique can hardly satisfy this demand. On the other hand, the narrow band property has become the trend of the next generation IoT, however, the problem of interference alleviation in the narrow band system is difficult to be resolved. Recently, the sparse code multiple access (SCMA), a non-orthogonal multiple access technique for 5G, shows the obvious improvement in user connectivity and system capacity. After carrier aggregation brought into the future network, The IoT could offer the frequency hopping mechanism larger bandwidth resources. In this paper, by introducing frequency hopping mechanism to the SCMA, a frequency-hopping based sparse code multiple access (FH-SCMA) multiple access technique is proposed to meet the demand of both massive connectivity and the improvement in the interference alleviation. Simulation results show that the FH-SCMA obtains a spectrum efficiency gain of almost 300% compared with the frequency division multiple access (FDMA) based IoT system with frequency-hopping, and the performance of interference alleviation can also be significantly improved by about 2 to 5 times over the FDMA with frequency hopping.

关键词： Internet of Things sparse code multiple access frequency-hopping NB-IoT

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Design and Analysis of Irregular sparse code multiple access

Design and Analysis of Irregular Sparse Code Multiple Access

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International Conference on Wireless Communications and Signal Processing

作者： Shutian Zhang Baicen Xiao Kexin Xiao Zhiyong Chen Bin Xia Dept. of Electron. Eng. Shanghai Jiao Tong Univ. Shanghai China

ISBN: (纸本)9781467376884

sparse code multiple access (SCMA) is an excellent approach to support massive connections and short time-delay, which are the two key requirements in the future fifth generation (5G) communication system. Due to the drawback that traditional SCMA can't serve users with different business needs in the same scenario, we propose an irregular sparse code multiple access (SCMA) in this paper. In contrast with the traditional SCMA system based on the regular structure, the irregular SCMA can handle massive connections and short time delay in the same system simultaneously by assigning different codebooks with various dimensions for different users who demand for divers performance needs. Simulation results illustrate that irregular SCMA can achieve about 0.7 dB gain over regular SCMA in terms of the same bit error rate (BER) condition.

关键词： 5G mobile communication codes error statistics multi-access systems synchronisation 5G communication system BER bit error rate codebooks fifth generation communication system irregular SCMA sparse code multiple access time-delay Business Complexity theory Receivers Time-frequency analysis Uplink

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SCMA-Q-learning with overload control for random access in LEO satellite mMTC networks

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PHYSICAL COMMUNICATION 2025年 69卷

作者： Wu, Zeyu Jing, Guoliang Ding, Jie Zhao, Xu Jiangsu Univ Sci & Technol Sch Comp Zhenjiang 212100 Jiangsu Peoples R China Guilin Univ Elect Technol Guangxi Key Lab Trusted Software Guilin 541004 Peoples R China Beijing SmartChip Microelect Technol Co Ltd Beijing 10000 Peoples R China

With the continuous advancement of 5G and beyond wireless networks, the exponential increase in Machine- Type Communication (MTC) devices presents substantial challenges, particularly in deal with Random access Channel (RACH) congestion in massive MTC (mMTC) networks. Low Earth Orbit (LEO) satellite communication networks are increasingly valued for their global coverage and low-latency benefits. This paper deals with the RACH congestion problem in LEO satellite networks by proposing an innovative method that combines sparse code multiple access (SCMA), Q-learning, and access Class Barring (ACB) technology. The proposed approach allows MTC devices to dynamically optimize resource allocation by selecting the most appropriate codebooks and time-slot groups in response to environmental changes. Additionally, ACB is employed to control system overload by adjusting the access probability of devices based on network conditions. Simulation results show that the proposed SCMA-QL-ACB method significantly improves system throughput and reduces collisions compared to existing techniques.

关键词： Random access Machine-type communications Q-learning sparse code multiple access access class barring

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Low Complexity Message Passing Receiver Design for SCMA-GFDM System

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IEEE TRANSACTIONS ON VEHICULAR TECHNOLOGY 2024年第12期73卷 18755-18768页

作者： Cheng, Hao Zhang, Min Zhang, Chuan Zhang, Haiyang Huang, Yongming Wang, Baoyun Nanjing Univ Posts & Telecommun Sch Internet Things Nanjing 210003 Peoples R China Southeast Univ Sch Informat Sci & Engn Nanjing 210096 Peoples R China Purple Mt Labs Nanjing 211111 Peoples R China Nanjing Univ Posts & Telecommun Sch Commun & Informat Engn Nanjing 210003 Peoples R China

sparse code multiple access (SCMA) and generalized frequency-division multiplexing (GFDM) are two promising techniques that can effectively handle massive connectivity and enhance spectrum efficiency in the sixth generation wireless communication systems. Unfortunately, the high computational cost of the SCMA-GFDM receiver limits its practical application. To this end, by virtue of the frequency domain implementation of the GFDM transmission, we apply the discrete fourier transform (DFT) operation on the received symbols, which in return diagonalizes the channel matrix. Next, this efficient received signal after DFT is put into the zero-forcing (ZF) equalizer of GFDM, and subsequently, fed into the message passing algorithm (MPA) receiver of SCMA, which establishes a low complexity multiuser detection for the SCMA-GFDM system. For rigor, the closed form average bit error ratio (BER) bound for this SCMA-GFDM system is also derived by computing the effective noise power. Finally, simulation results illustrate the robustness of the designed low complexity DFT-MPA detector in terms of BER performance, and also demonstrate the validity of the analytical BER bound.

关键词： Receivers NOMA Information filters Symbols Interference Complexity theory codes sparse code multiple access generalized frequency-division multiplexing DFT-MPA closed form bit error ratio

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High Security and Low Complexity SCMA-OFDM Transmission System Based on Dual Three-Dimensional Memory Hyperchaotic in Seven-Core Optical Fibers

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JOURNAL OF LIGHTWAVE TECHNOLOGY 2024年第16期42卷 5458-5465页

作者： Guo, Zeqian Liu, Bo Ren, Jianxin Mao, Yaya Wu, Xiangyu Chen, Shuaidong Ullah, Rahat Wu, Yongfeng Li, Ying Zhou, Shuyu Wu, Mengjie Ding, Zhongwen Cui, Jie Zhang, Juntao Nanjing Univ Informat Sci & Technol Inst Opt & Elect Nanjing 210044 Peoples R China Nanjing Univ Informat Sci & Technol Jiangsu Key Lab Optoelect Detect Atmosphere & Oce Jiangsu Int Joint Lab Meterol Photon & Optoelect Nanjing 210044 Peoples R China

This paper proposes a physical layer encryption scheme with high security and low complexity for sparse code multiple access (SCMA) in weakly coupled seven-core optical fibers, using orthogonal frequency division multiplexing (OFDM) modulation to improve the link quality of a single user. Due to the overload rate of SCMA and space division multiplexing, the number of users connected to the proposed system scheme has increased to 10.5 times. To improve the security of the SCMA-OFDM system, this paper adopts a memory triangular mapping (MTM) hyperchaotic model. After data preprocessing, its chaotic sequence is used to perturb the SCMA codebook, constellation, subcarriers, symbols, and time slots, and multidimensional scrambling is performed to prevent illegal users from eavesdropping. The key is placed behind the signal to achieve key accompanying signal transmission. The sphere decoding-based message passing algorithm (SD-MPA) is adopted at the receiver to solve the problem of high computational complexity. Experiments have proved that the encryption scheme for SCMA-OFDM signal transmission of 34.9 Gb/s effective information over 2 km of 7-core optical fiber has a key space of 10(343), verifying the security and robustness of the transmission system. In addition, the detection effects of different multiuser detection algorithms in SCMA-OFDM multicore optical fiber transmission systems are also studied.

关键词： Optical fibers Constellation diagram Encryption Symbols Optical modulation Optical fiber sensors Optical fiber networks High security hyperchaotic memory triangular mapping message passing algorithm sparse code multiple access

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RIS-Aided SCMA-Based SWIPT Systems: Design and Optimization

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IEEE TRANSACTIONS ON VEHICULAR TECHNOLOGY 2023年第5期72卷 6238-6252页

作者： Chai, Lingyun Bai, Lin Bai, Tong Choi, Jinho Zhang, Wei Beihang Univ Sch Elect & Informat Engn Beijing 100191 Peoples R China Beihang Univ Sch Cyber Sci & Technol Beijing 100191 Peoples R China Beihang Univ Beijing Lab Gen Aviat Technol Beijing 100191 Peoples R China Deakin Univ Sch Informat Technol Geelong Vic 3220 Australia Univ New South Wales Sch Elect Engn & Telecommun Sydney NSW 2052 Australia

The amalgamation of sparse code multiple access (SCMA) and simultaneous wireless information and power transfer (SWIPT) is envisioned to be a promising solution to massive connectivity while providing both information and power to myriads of wireless machines and sensors in Internet-of-Things (IoT) application. However, the benefit of the SCMA-based SWIPT system has not been fully exploited yet, especially when the communications link is hostile. Fortunately, the propagation-induced impairment can be mitigated by the emerging technique of reconfigurable intelligent surface (RIS). In this paper, we investigate the beneficial role of RIS in SCMA-based SWIPT systems, where $K$ single-antenna information receivers and one signal-antenna energy receiver are served by a multiple-antenna base station over $J$ orthogonal subcarriers with the aid of RIS. We propose transmit power minimization algorithms for both i) the perfect and ii) the imperfect channel state information (CSI) scenarios, by jointly optimizing the codebook assignment, the BS active beamforming, as well as RIS reflection coefficients, relying on advanced techniques both of alternating optimization and of successive convex approximations, and on the robust design framework. Furthermore, we compare and evaluate the detection performance of the system considered. The numerical results demonstrate that our proposed RIS-aided SCMA-based SWIPT system significantly outperforms the conventional SCMA-based SWIPT system without RIS and is capable of adapting to the imperfect full channel estimation results.

关键词： NOMA Wireless communication Downlink Optimization Base stations Array signal processing Wireless sensor networks sparse code multiple access simultaneous wireless information and power transfer reconfigurable intelligent surface imperfect channel state information

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