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A multiple copyright identification watermarking algorithm based on code division multiple access 认领 引用
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作者 张帆 li Jie +1 位作者 Su Yuting Zhang Chuntian 《High Technology Letters》 EI CAS 2008年第4期377-383,共7页
A multiple watermarking algorithm is presented according to the multiple accessing technique of the code division multiple access （CDMA） system. Multiple watermarks are embedded into digital images in the wavelet tr... A multiple watermarking algorithm is presented according to the multiple accessing technique of the code division multiple access （CDMA） system. Multiple watermarks are embedded into digital images in the wavelet transform domain. Each of the watermarks is embedded and extracted independently without impacts to each other. Multiple watermarks are convolution encoded and block interleaved, and the orthogonal Gold sequences are used to spread spectrum of the copyright messages. CDMA encoded water-mark messages are embedded into the wavelet sub-bands excluding the wavelet HH1 sub-bands. The embedment amplitude is decided by Watson＇ s perceptual model of wavelet transform domain, and the embedmeut position in the selected wavelet sub-bands is decided randomly by a pseudo-random noise （PN） sequence. As a blind watermm＇king algorithm, watermarks are extracted without original image. The watermarking capacity of proposed algorithm is also discussed. When two watermarks are embedded in an image at the same time, the capacity is larger than the capacity when a single watermark is embedded, and is smaller than the sum of the capacity of two separately embedded watermarks. Experimental results show that the proposed algorithm improves the detection bits error rate （BER） observably, and the multiple watermarks have a preferable robustness and invisibility. 展开更多
关键词 code division multiple access （CDMA） watermarking convolutional coding
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Joint power control based on service factor for code division multiple access system 认领 引用
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作者 陈波 戎蒙恬 胡威 《Journal of Shanghai University(English Edition)》 2008年第5期414-418,共5页
An important feature of the traffic in mobile networks is burstiness. Drawbacks of conventional power control algorithms for time division duplex （TDD）-code division multiple access （CDMA） systems are analyzed. A ... An important feature of the traffic in mobile networks is burstiness. Drawbacks of conventional power control algorithms for time division duplex （TDD）-code division multiple access （CDMA） systems are analyzed. A joint power control algorithm based on service factor is presented to address the TDD-CDMA mobile services in the burst mode according to the Markov modulated Bernoulli process. The joint power control equation is derived. A function model is developed to verify the new algorithm and evaluate its performance. Simulation results show that the new power control algorithm can estimate interference strength more precisely, speed up convergence of power control, and enhance power efficiency and system capacity. It is shown that the proposed algorithm is more robust against link gain changes, and outperforms the reference algorithms. 展开更多
关键词 code division multiple access （CDMA） time division duplex （TDD） power control Markov process service factor
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A passive optical network based on optical code division multiplexing and time division multiple access technology 认领 引用
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作者 张崇富 Qiu Kun 《High Technology Letters》 EI CAS 2007年第3期302-306,共5页
A passive optical network （PON） scheme based on optical code division multiplexing （OCDM） for the downstream traffics is proposed and analyzed in detail. In the PON, the downstream traffics are broadcasted by OCDM... A passive optical network （PON） scheme based on optical code division multiplexing （OCDM） for the downstream traffics is proposed and analyzed in detail. In the PON, the downstream traffics are broadcasted by OCDM technology to guarantee the security, while the upstream traffics pass through the same optical fiber by the common time division multiple access （TDMA） technology to decrease the cost. This schemes are denoted as OCDM/TDMA-PON, which can be applied to an optical access network （OAN） with full services on demand, such as Internet protocol, video on demand, tele-presence and high quality audio. The proposed OCDM/TDMA-PON scheme combines advantages of PON, TDMA, and OCDM technology. Simulation results indicate that the designed scheme improves the OAN performance, and enhances flexibility and scalability of the system. 展开更多
关键词 passive optical network （PON） optical code division multiplexing （OCDM） time division multiple access （TDMA） optical orthogonal code （OOC） optical line terminator （OLT） optical network units （ONU）
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Polar Coded Iterative Multiuser Detection for Sparse Code Multiple Access System 认领 引用 被引量：2
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作者 Hang MU Youhua Tang +3 位作者 Li Li Zheng Ma Pingzhi Fan Weiqiang Xu 《China Communications》 SCIE CSCD 2018年第11期51-61,共11页
Polar coded sparse code multiple access(SCMA) system is conceived in this paper. A simple but new iterative multiuser detection framework is proposed, which consists of a message passing algorithm(MPA) based multiuser... Polar coded sparse code multiple access(SCMA) system is conceived in this paper. A simple but new iterative multiuser detection framework is proposed, which consists of a message passing algorithm(MPA) based multiuser detector and a soft-input soft-output(SISO) successive cancellation(SC) polar decoder. In particular, the SISO polar decoding process is realized by a specifically designed soft re-encoder, which is concatenated to the original SC decoder. This soft re-encoder is capable of reconstructing the soft information of the entire polar codeword based on previously detected log-likelihood ratios(LLRs) of information bits. Benefiting from the soft re-encoding algorithm, the resultant iterative detection strategy is able to obtain a salient coding gain. Our simulation results demonstrate that significant improvement in error performance is achieved by the proposed polar-coded SCMA in additive white Gaussian noise(AWGN) channels, where the performance of the conventional SISO belief propagation(BP) polar decoder aided SCMA, the turbo coded SCMA and the low-density parity-check(LDPC) coded SCMA are employed as benchmarks. 展开更多
关键词 iterative multiuser receiver polarcode sparse code multiple access （SCMA）
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Reservation-based dynamic admission control scheme for wideband code division multiple access systems 认领 引用
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作者 A.Y.Al-nahari S.A.El-Dolil +1 位作者 M.I.Dessouky F.E.Abd El-Samie 《Journal of Central South University》 SCIE EI CAS 2012年第2期393-401,共9页
Call admission control (CAC) and resource reservation (RR) for mobile communication are two important factors that guarantee system efficiency and quality of service (QoS) required for different services in a very sca... Call admission control (CAC) and resource reservation (RR) for mobile communication are two important factors that guarantee system efficiency and quality of service (QoS) required for different services in a very scarce resource as the radio spectrum. A new scheme was proposed which extends the concepts of resource sharing and reservations for wideband code division multiple access (WCDMA) systems with a unique feature of soft capacity. Voice and data traffic were considered. The traffic is further classified into handoff and new requests. The reservation thresholds were dynamically adjusted according to the traffic pattern and mobility prediction in order to achieve the maximum channel utilization, while guaranteeing different QoS constraints. The performance of proposed scheme was evaluated using Markov models. New call blocking probability, handoff call dropping probability, and channel utilization were used as benchmarks for the proposed scheme. 展开更多
关键词 admission control resource reservation wideband code division multiple access resource utilization
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Performance analysis of quantum access network using code division multiple access model 认领 引用
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作者 胡林曦 杨灿 何广强 《Chinese Physics B》 SCIE EI CAS CSCD 2017年第6期37-41,共5页
A quantum access network has been implemented by frequency division multiple access and time division multiple access, while code division multiple access is limited for its difficulty to realize the orthogonality of ... A quantum access network has been implemented by frequency division multiple access and time division multiple access, while code division multiple access is limited for its difficulty to realize the orthogonality of the code. Recently,the chaotic phase shifters were proposed to guarantee the orthogonality by different chaotic signals and spread the spectral content of the quantum states. In this letter, we propose to implement the code division multiple access quantum network by using chaotic phase shifters and synchronization. Due to the orthogonality of the different chaotic phase shifter, every pair of users can faithfully transmit quantum information through a common channel and have little crosstalk between different users. Meanwhile, the broadband spectra of chaotic signals efficiently help the quantum states to defend against channel loss and noise. 展开更多
关键词 quantum access network chaotic phase shifter code division multiple access
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Analysis and Simulation for Capacity of Time Division-Synchronous Code Division Multiple Access System 认领 引用 被引量：1
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作者 Sun Chengjun, Zhang Zhongzhao, Ba Yong2 & Cao Pengzhi (Communication Research ("enter, Harbin Institute of Technology, Harbin 150001, P. R. China Department of Electronic Engineering, Tsinghua University, Beijing 100084, P. R. China Research and Development Division, Shanghai Bell Company Limited, Shanghai 200092, P. R. China) 《Journal of Systems Engineering and Electronics》 2002年第4期91-97,共7页
Capcity both in uplink and downlink of TD-SCDMA (time division-synchronous code division multiple access) system is studied in a multi-cell environment. The theoretical expressions of the mean of intercell interferenc... Capcity both in uplink and downlink of TD-SCDMA (time division-synchronous code division multiple access) system is studied in a multi-cell environment. The theoretical expressions of the mean of intercell interference in uplink and the mean of sum of power allocation in downlink are given, by which uplink and downlink capacity is analyzed. Furthermore, we give the simulation models for both uplink and downlink capacity. The results from theoretical analysis and simulation fit very well. In the end, the maximum number of users that TD-SCDMA system can serve for 12.2 k speech service is given. 展开更多
关键词 Code division multiple access Probability Resource allocation Simulation Time division multiple access
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Performance Analysis of Multiple User Optical Code Division Multiple Access 认领 引用
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作者 Himanshu Monga R. S. Kaler 《Optics and Photonics Journal》 2014年第2期21-25,共5页
In this paper, we discuss and analyze an optical code division multiple access for multiple user system. Media access control implementation has been considered. For fulfilling the huge need of bandwidth services, tec... In this paper, we discuss and analyze an optical code division multiple access for multiple user system. Media access control implementation has been considered. For fulfilling the huge need of bandwidth services, technology tends to move to optical networks and three major optical systems come into existence. Code division of the optical network is most used and real concept interacted with users up to this time. Optical code division multiple access provides complete spectrum to each and every user for the time of accessing the channel. In the paper, we have proposed network architecture with optical encoder and decoder along with optical code translator which is supporting multiple user systems. We integrate the code translator with encoding and decoding of optical code to use the optical network at full extent and present the simulation validation results of 6 Gb/s 3-hop transmission by use of proposed architecture. Further, we have implemented experimentation with 6 users 3 Gb/s optical code division multiple access network. Through simulation structure, it is shown that the combination of encoding with EDFA in multiple user environment system provides improvement in bit error rate and also improves the multiple access interference. With increase of users in the network, MAI value increases and our proposed scheme controls interference in the network. 展开更多
关键词 Optical Code Division Multiple Access Strong Interference Weak Interference Bit Error Rate Optical Encoding Laser Diode Source Multiple Access Interference
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Low-Complexity Codebook Design for SCMA-Assisted Indoor Visible Light Communication Systems 认领 引用
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作者 Wang Yuhao Xu Chuan +3 位作者 Yu Lisu Lyu Xinxin Chen Junyuan Wang Zhenghai 《China Communications》 SCIE EI CSCD 2025年第6期180-192,共13页
Sparse code multiple access(SCMA)is a non-orthogonal multiple access(NOMA)scheme based on joint modulation and spread spectrum coding.It is ideal for future communication networks with a massive number of nodes due to... Sparse code multiple access(SCMA)is a non-orthogonal multiple access(NOMA)scheme based on joint modulation and spread spectrum coding.It is ideal for future communication networks with a massive number of nodes due to its ability to handle user overload.Introducing SCMA into visible light communication(VLC)systems can improve the data transmission capability of the system.However,designing a suitable codebook becomes a challenging problem when addressing the demands of massive connectivity scenarios.Therefore,this paper proposes a low-complexity design method for high-overload codebooks based on the minimum bit error rate(BER)criterion.Firstly,this paper constructs a new codebook with parameters based on the symmetric mother codebook structure by allocating the codeword power so that the power of each user codebook is unbalanced;then,the BER performance in the visible light communication system is optimized to obtain specific parameters;finally,the successive interference cancellation(SIC)detection algorithm is used at the receiver side.Simulation results show that the method proposed in this paper can converge quickly by utilizing a relatively small number of detection iterations.This can simultaneously reduce the complexity of design and detection,outperforming existing design methods for massive SCMA codebooks. 展开更多
关键词 high overload low-complexity codebook design sparse code multiple access(SCMA) successive interference cancellation(SIC) visible light communication(VLC)
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A Novel Progressive Edge Growth-Based Codebook Design for SCMA Systems 认领 引用
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作者 Lei Tuofeng Ni Shuyan +2 位作者 Luo Qu Chen Shimiao Xiao Pei 《China Communications》 SCIE EI CSCD 2025年第6期116-130,共15页
This paper proposes a class of novel progressive edge growth-based codebooks for downlink sparse code multiple access(SCMA)systems.In the first scheme,we propose to progressively design the codebooks of each resource ... This paper proposes a class of novel progressive edge growth-based codebooks for downlink sparse code multiple access(SCMA)systems.In the first scheme,we propose to progressively design the codebooks of each resource node(RN)instead of rotating a mother constellation(MC)as in the conventional SCMA works.In the other one,based on the MC,a multi-resources rotated codebooks are proposed to improve the performance of the superimposed constellations.The resultant codebooks are respectively referred to as the resource edge multidimensional codebooks(REMC)and the user edge multi-dimensional codebooks(UEMC).Additionally,we delve into the detailed design of the MC and the superimposed constellation.Then,we pay special attention to the application of the proposed schemes to challenging design cases,particularly for the high dimensional,high rate,and irregular codebooks,where the corresponding simplified schemes are proposed to reduce the complexity of codebook design.Finally,simulation results are presented to demonstrate the superiority of our progressive edge growth-based schemes.The numerical results indicate that the proposed codebooks significantly outperform the stateof-the-art codebooks.In addition,we also show that the proposed REMC codebooks outperform in the lower signal-to-noise ratio(SNR)regime,whereas the UEMC codebooks exhibit better performance at higher SNRs. 展开更多
关键词 codebook design resource edge multidimensional codebooks(REMC) sparse code multiple access(SCMA) symbol error performance user edge multi-dimensional codebooks(UEMC)
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A Low Complexity VCS Method for PAPR Reduction in Multicarrier Code Division Multiple Access 认领 引用
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作者 Si-Si Liu Yue Xiao Qing-Song Wen Shao-Qian Li 《Journal of Electronic Science and Technology of China》 2007年第2期102-106,共5页
This paper investigates a peak to average power ratio （PAPR） reduction method in multicarrier code division multiple access （MC-CDMA） system. Variable code sets （VCS）, a spreading codes selection scheme, can imp... This paper investigates a peak to average power ratio （PAPR） reduction method in multicarrier code division multiple access （MC-CDMA） system. Variable code sets （VCS）, a spreading codes selection scheme, can improve the PAPR property of the MC-CDMA signals, but this technique requires an exhaustive search over the combinations of spreading code sets. It is observed that when the number of active users increases, the search complexity will increase exponentially. Based on this fact, we propose a low complexity VCS （LC-VCS） method to reduce the computational complexity. The basic idea of LC-VCS is to derive new signals using the relationship between candidature signals. Simulation results show that the proposed approach can reduce PAPR with lower comtational pucomplexity. In addition, it can be blindly received without any side information. 展开更多
关键词 Low complexity variable code sets,multicarrier code division multiple access （MC-CDMA）,peak to average power ratio variable code sets.
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107 MHz point acquisition ultrafast 3D imaging via optical code-division multiple access 认领 引用
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作者 PENG TIAN SHUJIAN GONG +8 位作者 XIAOYIN LI YINGHUI GUO MINGBO PU QI ZHANG HEPING LIU MINGFENG XU FEI ZHANG JIANPING SHI XIANGANG LUO 《Photonics Research》 SCIE EI CAS CSCD 2026年第4期1359-1372,共14页
High-speed 3D perception in dynamic environments requires LiDAR systems with extremely high point acquisition rates(PARs).Existing methods for increasing PARs often involve complex hardware setups yet remain limited i... High-speed 3D perception in dynamic environments requires LiDAR systems with extremely high point acquisition rates(PARs).Existing methods for increasing PARs often involve complex hardware setups yet remain limited in speed,failing to meet the demands of high-dynamic-range sensing.We propose an all-optical encoded ultrafast LiDAR based on optical code-division multiple access(OCDMA).By decomposing a broadband source into 40 spectral channels via wavelength-division multiplexing(WDM)and applying six-pulse sequence encoding through fiber-delay-line-based all-optical encoding,we achieve simultaneous emission and independent decoding of all channels.Leveraging exceptional code orthogonality and the inherently narrow pulse width of all-optical encoding,a PAR of 107.6 MHz—one that surpasses all existing counterparts within the same architectural category by an order of magnitude—and a ranging accuracy of~3 mm are demonstrated.We further showcase highfidelity 3D reconstruction of static targets and dynamic imaging of a chopper,achieving a high frame rate of 10.8 kHz(83×120 points)by inter-axis rate matching of spectral-acousto-optic scanning.The system architecture offers high integration compatibility and provides a feasible technological pathway for next-generation highspeed autonomous driving and industrial vision systems. 展开更多
关键词 Dynamic Environments Point Acquisition Rate High Speed D Perception Fiber Delay Line Based Encoding Ultrafast Lidar complex hardware setups Optical Code Division Multiple Access Wavelength Division Multiplexing
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空间色噪声干扰下基于白化的SCMA检测技术 认领 引用
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作者 秦天柱 王秋实 +2 位作者 张轩博 韩凯宁 胡剑浩 《电子科技大学学报》 EI CAS CSCD 北大核心 2026年第4期481-487,共7页
为解决超密集无线网络中空间有色干扰的挑战,提出了一种结合白化处理的新型上行稀疏码分多址接入(SCMA)检测框架。首先,采用白化处理技术对空间有色干扰进行去相关,并提出一种基于白化的消息传递算法(W-MPA)以提升检测性能。其次,为解决... 为解决超密集无线网络中空间有色干扰的挑战,提出了一种结合白化处理的新型上行稀疏码分多址接入(SCMA)检测框架。首先,采用白化处理技术对空间有色干扰进行去相关,并提出一种基于白化的消息传递算法(W-MPA)以提升检测性能。其次,为解决W-MPA算法的高复杂度问题,进一步提出一种基于白化的去中心化期望传播算法(W-DEPA),该算法将去中心化处理与近似分布传递原理协同融合以实现低复杂度运算。仿真结果表明,白化技术能有效抑制SCMA系统中的共道干扰和窄带干扰等色噪声干扰。此外,W-DEPA不仅拥有与W-MPA相当的检测性能,而且显著降低了计算复杂度。 展开更多
关键词 稀疏码分多址接入 空间有色干扰 白化 期望传播
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Design Framework of Unsourced Multiple Access for 6G Massive IoT 认领 引用 被引量：3
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作者 Chunlin Yan Siying Lyu +2 位作者 Sen Wang Yuhong Huang Xiaodong Xu 《China Communications》 SCIE CSCD 2024年第1期1-12,共12页
In this paper,ambient IoT is used as a typical use case of massive connections for the sixth generation(6G)mobile communications where we derive the performance requirements to facilitate the evaluation of technical s... In this paper,ambient IoT is used as a typical use case of massive connections for the sixth generation(6G)mobile communications where we derive the performance requirements to facilitate the evaluation of technical solutions.A rather complete design of unsourced multiple access is proposed in which two key parts:a compressed sensing module for active user detection,and a sparse interleaver-division multiple access(SIDMA)module are simulated side by side on a same platform at balanced signal to noise ratio(SNR)operating points.With a proper combination of compressed sensing matrix,a convolutional encoder,receiver algorithms,the simulated performance results appear superior to the state-of-the-art benchmark,yet with relatively less complicated processing. 展开更多
关键词 channel coding compressed sensing massive Internet-of-Things(IoT) sparse interleaverdivision multiple access(SIDMA) the sixth generation(6G)mobile communications unsourced multiple access
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卫星物联网中基于状态位置信息的低复杂度SCMA多用户检测算法 认领 引用
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作者 甄立 王嘉浩 +1 位作者 何华 卢光跃 《物联网学报》 2025年第1期71-81,共11页
卫星物联网是6G实现万物智联的关键所在,而其频谱资源和星上载荷的双重受限性,给海量用户的接入效能提升带来严峻挑战。针对稀疏码多址接入(SCMA,sparse code multiple access)星载接收机多用户检测效率低下问题,考虑迭代过程中码字发... 卫星物联网是6G实现万物智联的关键所在,而其频谱资源和星上载荷的双重受限性,给海量用户的接入效能提升带来严峻挑战。针对稀疏码多址接入(SCMA,sparse code multiple access)星载接收机多用户检测效率低下问题,考虑迭代过程中码字发送概率的差异性,提出一种基于状态位置信息的对数域消息传递算法(SPI-Log-MPA,state position information based log message passing algorithm)。该算法根据用户码字状态位置的变化情况,在迭代检测过程中通过减少不可靠码字、提前对稳定用户进行解码、设立奖惩机制对非稳定用户进行解码等措施,显著提升了检测效率。在此基础上,对阶段设置与状态位置信息矩阵两方面进行优化,提出两阶段的改进算法,进一步加快了收敛速度。复杂度分析与仿真结果表明,所提算法在保证误码率性能的前提下具有更低的计算复杂度。 展开更多
关键词 卫星物联网 稀疏码多址接入 多用户检测 消息传递算法 状态位置信息
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A genetic algorithm based hybrid non-orthogonal multiple access protocol 认领 引用 被引量：1
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作者 YAN Zhenzhen YANG Mao YAN Zhongjiang 《High Technology Letters》 EI CAS 2022年第1期1-9,共9页
Both high-dense wireless connectivity and ultra-huge network capacity are main challenges of next generation broadband networks.As one of its key promising technologies,non-orthogonal multi-ple access(NOMA)scheme can ... Both high-dense wireless connectivity and ultra-huge network capacity are main challenges of next generation broadband networks.As one of its key promising technologies,non-orthogonal multi-ple access(NOMA)scheme can solve those challenges and meet those needs to some extent,in the way that different user equipments(UEs)multiplex on the same resource.Researchers around the world have presented numerous NOMA solutions.Among those,sparse code multiple access(SC-MA)technology is a typical NOMA solution.It supports scheduled access and random access which can be called granted access and grant-free access respectively.But resources allocated to granted UEs and grant-free UEs are strictly separated.In order to improve resource utilization,a hybrid non-orthogonal multiple access scheme is proposed.It allows granted UEs and grant-free UEs sharing the same resource unit in terms of fine-grained integration.On the basis,a resource allocation method is further brought forward based on genetic algorithm.It optimizes resource allocation of all UEs by mapping resource distribution issue to an optimization problem.Comparing throughputs of four meth-ods,simulation results demonstrate the proposed genetic algorithm has better throughput gain. 展开更多
关键词 non-orthogonal multiple access(NOMA) resource allocation sparse code multiple access(SCMA) genetic algorithm hybrid non-orthogonal multiple access
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Hybrid Deep Learning-Based Adaptive Multiple Access Schemes Underwater Wireless Networks 认领 引用
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作者 D.Anitha R.A.Karthika 《Intelligent Automation & Soft Computing》 SCIE 2023年第2期2463-2477,共15页
Achieving sound communication systems in Under Water Acoustic(UWA)environment remains challenging for researchers.The communication scheme is complex since these acoustic channels exhibit uneven characteristics such a... Achieving sound communication systems in Under Water Acoustic(UWA)environment remains challenging for researchers.The communication scheme is complex since these acoustic channels exhibit uneven characteristics such as long propagation delay and irregular Doppler shifts.The development of machine and deep learning algorithms has reduced the burden of achieving reli-able and good communication schemes in the underwater acoustic environment.This paper proposes a novel intelligent selection method between the different modulation schemes such as Code Division Multiple Access(CDMA),Time Divi-sion Multiple Access(TDMA),and Orthogonal Frequency Division Multiplexing(OFDM)techniques using the hybrid combination of the convolutional neural net-works(CNN)and ensemble single feedforward layers(SFL).The convolutional neural networks are used for channel feature extraction,and boosted ensembled feedforward layers are used for modulation selection based on the CNN outputs.The extensive experimentation is carried out and compared with other hybrid learning models and conventional methods.Simulation results demonstrate that the performance of the proposed hybrid learning model has achieved nearly 98%accuracy and a 30%increase in BER performance which outperformed the other learning models in achieving the communication schemes under dynamic underwater environments. 展开更多
关键词 Code division multiple access time division multiple access convolutional neural networks feedforward layers
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Low-complexity channel estimation and LMS-based tracking scheme for uplink SCMA-OFDM systems 认领 引用
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作者 GUO Liting ZHOU Lichao +4 位作者 PING Shiyao SHI Changwei KANG Peng DU Weiqing CHEN Pingping 《High Technology Letters》 EI CAS 2025年第3期238-245,共8页
Channel state information(CSI)is very important to sparse code multiple access combined with orthogonal frequency division multiplexing(SCMA-OFDM)systems for data detection.The main goal of this paper is to tackle the... Channel state information(CSI)is very important to sparse code multiple access combined with orthogonal frequency division multiplexing(SCMA-OFDM)systems for data detection.The main goal of this paper is to tackle the computational complexity and pilot overhead issues when estima-ting and tracking the channel frequency response of each user in uplink SCMA-OFDM systems.To this end,a new binary pilot structure is first designed to realize the initial channel estimation with significantly reduced computational complexity.Then,a channel tracking method is proposed to update the channel estimation in time-varying channels,which exploits a modified least mean square(LMS)technique with the feedback from the detector.Simulation results show that the pro-posed pilot structure can provide accurate channel estimation results.Moreover,the average bit error rate(BER)performance of the modified LMS algorithm can approach that of a detector with perfect CSI within 2 dB at the normalized Doppler frequency up to 6×10-6. 展开更多
关键词 channel estimation channel tracking least mean square uplink sparse code multiple access orthogonal frequency division multiplexing
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一种基于生成对抗网络的SCMA系统设计方法 认领 引用
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作者 段超 朱齐媛 +1 位作者 罗俊 龙世瑜 《韶关学院学报》 2025年第2期25-30,共6页
针对5G及未来移动通信系统中的稀疏码多址接入(SCMA)面临的最优码本设计和高效译码算法的挑战,提出了一种基于生成对抗网络(GAN)的SCMA系统方案.方案在编码器中引入Transformer架构的注意力机制,利用上下文信息降低码本设计的复杂度并... 针对5G及未来移动通信系统中的稀疏码多址接入(SCMA)面临的最优码本设计和高效译码算法的挑战,提出了一种基于生成对抗网络(GAN)的SCMA系统方案.方案在编码器中引入Transformer架构的注意力机制,利用上下文信息降低码本设计的复杂度并提升灵活性;在译码器中应用Patch GAN技术,减少网络模型参数量和运算量,简化传统译码算法,提高纠正误码性能.实验结果表明,方案在瑞利衰落信道条件下显著提升了SCMA系统的纠正误码性能,同时降低了实现复杂度.研究为5G及未来移动通信系统中的多址接入方案提供了新的视角和解决方案. 展开更多
关键词 稀疏码多址接入 深度学习 生成对抗网络 Transformer
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基于星座图分割的稀疏码分多址接入码本设计 认领 引用
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作者 王宏 徐川 +2 位作者 徐小涛 刘向阳 赵涛 《重庆邮电大学学报（自然科学版）》 CSCD 北大核心 2026年第2期265-273,共9页
针对母星座旋转法设计的稀疏码分多址接入(sparse code multiple access,SCMA)码本存在的复合星座点之间最小欧氏距离和平均功率难以兼顾的问题,提出一种基于复合星座图分割的SCMA码本设计方法。不同于传统的“由母星座变换得到用户码... 针对母星座旋转法设计的稀疏码分多址接入(sparse code multiple access,SCMA)码本存在的复合星座点之间最小欧氏距离和平均功率难以兼顾的问题,提出一种基于复合星座图分割的SCMA码本设计方法。不同于传统的“由母星座变换得到用户码本”的码本设计思路,该方法设计信道资源块上的复合星座图,确保星座点之间的最小欧氏距离满足要求,将复合星座图分割形成用户子星座,映射扩展为用户码本。理论分析表明,在平均功率相等的前提下,提出的方法码本复合星座图星座点之间的最小欧氏距离相较基于母星座旋转改善了3.94 dB;仿真分析表明,提出的方法相较基于母星座旋转,在相同误比特率(bit error rate,BER)的前提下码本信噪比改善了约2 dB。 展开更多
关键词 稀疏码分多址接入 星座图分割 码本设计 母星座旋转
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