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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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A Low-Complexity Codebook Design Scheme for SCMA Systems Over an AWGN Channel

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IEEE TRANSACTIONS ON VEHICULAR TECHNOLOGY 2022年第8期71卷 8675-8688页

作者： Zheng, Yu Xin, Jiantao Wang, Hui Zhang, Shengli Qiao, Yongjie Shenzhen Univ Coll Elect & Informat Engn Shenzhen 518060 Peoples R China Peng Cheng Lab Shenzhen 518000 Peoples R China

As a promising wireless access technique, sparse code multiple access (SCMA) directly maps the input bits to the transmitted multidimensional codewords according to the SCMA codebook. In general, SCMA codebook optimization and detector simplification are independent of each other. In this article, we propose a simplified SCMA codebook with a separable structure for implementing a low-complexity detector. For codebook design, a separable codebook structure is proposed to simplify the maximization of the minimum Euclidean distance (MED). With this structure, multiple one-dimensional complex codebooks corresponding to one resource element (RE) are determined by maximizing the MED of the superimposed codewords. Then, the entire codebook set is obtained based on a structure indicator matrix and the separable codebook structure. The proposed codebook has a larger MED than obtained by existing codebooks. Benefiting from the separable codebook structure, the signals transmitted over each RE can be independently used to recover the corresponding input bit information. Therefore, we propose a parallel maximum a posteriori (P-MAP) detector consisting of several low-complexity MAP detectors to reduce the complexity of the conventional multiuser message passing (MP) detector in SCMA. At the receiver, each RE is assigned a low-complexity MAP detector. Simulation results show that the proposed codebook outperforms the known optimal codebook over an AWGN channel. Moreover, the run time of the P-MAP detection algorithm is reduced by 99.8% compared to the Log-MPA algorithm. With the proposed codebook design scheme and the P-MAP detector, an SCMA unit can be separated into two independent non-SCMA units, which significantly increases system flexibility.

关键词： Codebook design low-complexity detector minimum euclidean distance (MED) message passing algorithm sparse code multiple access (SCMA)

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A combined BP-MF algorithm for wideband off-grid DOA estimation with DP prior

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ELECTRONICS LETTERS 2022年第25期58卷 1002-1005页

作者： Li, Mengge Lu, Xinhua Li, Ji Guan, Shanwen Guilin Univ Elect Technol Sch Comp Sci & Informat Secur Guilin Peoples R China Nanyang Inst Technol Sch Informat Engn Nanyang Peoples R China

Direction-of-arrival (DOA) estimation based on sparse Bayesian learning (SBL) framework has attracted extensive attention. The accuracy of on-grid DOA estimation is restricted by the prescribed grid, while off-grid approaches resolves the problem of grid mismatch partly. This letter deals with off-grid DOA estimation problem of wideband signals. A factor graph is designed to describe the problem with Dirichlet process (DP) prior, which clusters the sparse structure of wideband signals. The authors employ the combined belief propagation-mean field (BP-MF) rule on the factor graph and lead to a message passing algorithm. Simulation results verify the superiority of the proposed combined BP-MF algorithm for off-grid DOA estimation compared to other state-of-art methods.

关键词： DP prior sparse Bayesian learning belief propagation message passing SBL Dirichlet process prior wideband signals belief propagation-mean field rule Bayes methods direction-of-arrival estimation grid mismatch wideband off-grid DOA estimation BP-MF algorithm graph theory message passing algorithm sparse structure factor graph learning (artificial intelligence)

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Adaptive Resource Allocation Based on Factor Graphs in Non-Orthogonal Multiple Access

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IEICE TRANSACTIONS ON COMMUNICATIONS 2022年第10期E105B卷 1258-1267页

作者： Yamagami, Taichi Denno, Satoshi Hou, Yafei Okayama Univ Grad Sch Nat Sci & Technol Okayama 7008530 Japan

In this paper, we propose a non-orthogonal multiple access with adaptive resource allocation. The proposed non-orthogonal multiple access assigns multiple frequency resources for each device to send pack-ets. Even if the number of devices is more than that of the available frequency resources, the proposed non-orthogonal access allows all the de-vices to transmit their packets simultaneously for high capacity massive machine-type communications (mMTC). Furthermore, this paper proposes adaptive resource allocation algorithms based on factor graphs that adap-tively allocate the frequency resources to the devices for improvement of the transmission performances. This paper proposes two allocation algorithms for the proposed non-orthogonal multiple access. This paper shows that the proposed non-orthogonal multiple access achieves superior transmis-sion performance when the number of the devices is 50% greater than the amount of the resource, i.e., the overloading ratio of 1.5, even without the adaptive resource allocation. The adaptive resource allocation enables the proposed non-orthogonal access to attain a gain of about 5 dB at the BER of 10-4.

关键词： non-orthogonal multiple access message passing algorithm factor graphs log-likelihood ratio

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OTFS Channel Estimation and Data Detection Designs With Superimposed Pilots

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IEEE TRANSACTIONS ON WIRELESS COMMUNICATIONS 2022年第4期21卷 2258-2274页

作者： Mishra, Himanshu B. Singh, Prem Prasad, Abhishek K. Budhiraja, Rohit IIT Dhanbad Dept Elect Engn Dhanbad 826004 Bihar India IIIT Bangalore Bengaluru 560100 India IIT Kanpur Dept Elect Engn Kanpur 208016 Uttar Pradesh India

We propose a superimposed pilot (SP)-based channel estimation and data detection framework for orthogonal time-frequency space (OTFS) systems, which superimposes low-powered pilots on to data symbols in the delay-Doppler domain. We propose two channel estimation and data detection designs for SP-OTFS systems which, unlike the existing OTFS designs, do not designate any slots for pilots, and consequently have higher spectral efficiency (SE). The first SP design estimates channel by treating data as interference, which degrades its performance at high signal to noise ratio. The second SP design alleviates this problem by iterating between channel estimation and data detection. Both these designs detect data using message passing algorithm which exploits OTFS channel sparsity, and consequently has low computational complexity. We also derive a lower bound on the signal-to-interference-plus-noise ratio of the proposed designs and maximize it by optimally allocating power between data and pilot symbols. We numerically validate the derived analytical results, and show that the proposed designs have superior SE than the existing OTFS channel estimation and data detection designs.

关键词： Channel estimation Time-frequency analysis Delays Interference Wireless communication OFDM Signal to noise ratio message passing algorithm orthogonal time-frequency space (OTFS) scheme superimposed pilots

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A Novel Non-Coherent SCMA With Massive MIMO

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IEEE WIRELESS COMMUNICATIONS LETTERS 2022年第11期11卷 2250-2254页

作者： Luo, Qu Wen, Haifeng Chen, Gaojie Liu, Zilong Xiao, Pei Ma, Yi Maaref, Amine Univ Surrey 5G & 6G Innovat Ctr Guildford GU2 7XH Surrey England Hong Kong Univ Sci & Technol Guangzhou Informat Hub Guangzhou Peoples R China Univ Essex Sch Comp Sci & Elect Engn Colchester CO4 3SQ Essex England Huawei Technol Co Ltd Canada Res Ctr Ottawa ON K2K 3J1 Canada

The synergistic amalgamation of sparse code multiple access (SCMA) and multiple-input multiple-output (MIMO) technologies can be exploited for improving spectral efficiency and providing enhanced wireless services to massive users. In this case, however, channel estimation is a burning issue with the increasing number of users and/or antennas. To tackle this problem, we propose a novel non-coherent transmission scheme for SCMA, referred to as NC-SCMA. In the proposed NC-SCMA, each user first maps its binary data to sparse codewords, and then perform differential modulation on the non-zero dimensions. Upon receiving all users' signals, we leverage the channel hardening effect to carry out differential demodulation and multi-user detection without any instantaneous channel state information. In addition, the design of the sparse codebooks in the NC-SCMA system is investigated with the aid of the pair-wise probability. Numerical results demonstrate the superiority of the proposed technique over the benchmark scheme in terms of bit error rate performance.

关键词： SCMA massive MIMO differential modulation non-coherent transmission message passing algorithm

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Reduced Complexity Resource Allocation For Frequency Domain Non-orthogonal Multiple Access

Reduced Complexity Resource Allocation For Frequency Domain ...

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IEEE Wireless Communications and Networking Conference (WCNC)

作者： Denno, Satoshi Yamagami, Taichi Hou, Yafei Okayama Univ Grad Sch Nat Sci & Technol 3-1-1 Tsushima NakaKita Okayama 7008530 Japan

ISBN: (纸本)9781665491228

This paper proposes low complexity resource allocation in frequency domain non-orthogonal multiple access where many devices access with a base station. The number of the devices is assumed to be more than that of the resource for network capacity enhancement, which is demanded in massive machine type communications (mMTC). This paper proposes two types of resource allocation techniques, which are named as "CGVS" and "LLRVS", all of which are based on the MIN-MAX approach. CGVS seeks for nicer resource allocation with only channel gains, while LLRVS applies the message passing algorithm (MPA) for better resource allocation. The proposed resource allocation techniques are evaluated by computer simulation in frequency domain non-orthogonal multiple access. Whereas LLRVS achieves only 0.1dB better performance than CGVS in the multiple access with the overloading ratio of 1.5 at the BER of 10(-4), CGVS can be implemented with 10(-5) smaller computational complexity than LLRVS. CGVS attains a gain of about 10dB at the BER of 10(-4) in the multiple access with the overloading ration of 2.0. The complexity of CGVS is 10(-16) as small as the conventional technique.

关键词： Non-orthogonal access low complexity message passing algorithm subcarrier allocation

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Cooperative Multi-User Detection for Satellite IoT under Constrained ISLs 34

Cooperative Multi-User Detection for Satellite IoT under Con...

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IEEE 34th Annual International Symposium on Personal, Indoor and Mobile Radio Communications (PIMRC)

作者： Miao, Sirui Ye, Neng Ouyang, Qiaolin Wang, Peisen Li, Xiangming Zhao, Lian Beijing Inst Technol Sch Cyberspace Sci & Technol Beijing Peoples R China Beijing Inst Technol Sch Informat & Elect Beijing Peoples R China Toronto Metropolitan Univ Dept Elect Comp & Biomed Engn Toronto ON Canada

ISBN: (纸本)9781665464833

The densely deployment of satellites enables the realization of direct-to-satellite Internet-of-things system with tremendous terminals through multi-satellite cooperation. Multi-user detection (MUD) based on cooperative satellite network can dramatically increase the detection performance. However, it is chained by the limited number of inter-satellite link (ISL) bandwidth resources. To cope with the stringent constraints on ISLs, we propose a novel auxiliary node (AN)-aided factor graph and the corresponding multi-user detection (MUD) algorithm named auxiliary node-cooperative message passing algorithm (AN-CMPA). Simulation results show that our proposed algorithm achieves only 0.5dB loss with 75% decreased information cost under effectively designed information filter criterion.

关键词： Multi-user detection message passing algorithm inter-satellite link

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A Multi-Overloading-Factor Sparse Code Multiple Access Decoder for 5G Communications 49

A Multi-Overloading-Factor Sparse Code Multiple Access Decod...

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IEEE 49th European Solid-State Circuits Conference (ESSCIRC)

作者： Lin, Zhi-Jing Chen, Ti-Yu Chiueh, Tzi-Dar Natl Taiwan Univ Grad Inst Elect Engn Taipei Taiwan Mediatek Inc Hsinchu Taiwan

ISBN: (纸本)9798350304206

This paper presents a multi-overloading-factor sparse code multiple access (SCMA) decoder IC for 5G massive machine-type communications. This design supports three different overloading factors. We applied the delayed update technique and an early-stop method to the message-passing algorithm (MPA) for better pipeline and decoding efficiency. Moreover, novel techniques, such as common term reuse, approximate distance, and sum/max circuit sharing, significantly reduce the circuit complexity and critical path delays. At 560MHz, the 40nm decoder IC achieves 2.777 Gbps/mm(2) area efficiency and 46.8pJ/b energy with 152.7Mbps throughput. The decoder can achieve maximum energy efficiency of 28pJ/b when working at 0.66V Vdd and 360MHz clock rate.

关键词： 5G sparse code multiple access message passing algorithm decoder IC early stop

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Iterative Symbol Decision Schemes for CP-OTFS on Static Multipath Channels

Iterative Symbol Decision Schemes for CP-OTFS on Static Mult...

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International Conference on Computing, Networking and Communications (ICNC)

作者： Tsai, Shuen-Yu Chen, Wei-Chang Chung, Char-Dir Realtek Inc Hsinchu Taiwan Natl Taipei Univ Technol Dept Elect Engn Taipei Taiwan Natl Taiwan Univ Grad Inst Commun Engn Taipei Taiwan

ISBN: (纸本)9781665457194

Orthogonal time frequency space (OTFS) systems have gained great attention in wireless communications due to achievable prominent error performance characteristics on high-mobility and static multipath channels. In this paper, two symbol decision schemes are proposed for the cyclic-prefixed OTFS system on static multipath channels by virtue of iterative decision-feedback hybrid equalization (IDFHE) using linear minimum mean-square-error (LMMSE) equalization rule and message-passing algorithm (MPA) as the respective first-iteration decision rule. The proposed LM-IDFHE and MPA-IDFHE schemes can exploit the advantages that inter-symbol interference is suppressed progressively over iterations and noise power enhancement is avoided at the final iteration. From simulation results, LM-IDFHE and MPA-IDFHE schemes are shown to outperform non-iterative LMMSE, iterative LMMSE, and iterative MPA schemes remarkably in average error performance on Rician multipath channels.

关键词： Orthogonal time frequency space modulation iterative decision-feedback hybrid equalization message passing algorithm static multipath channels

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