最新刊期
卷 49 ， 期 10 ， 2021
- 摘要：Aiming to fix the data loss problem of optical camera communication (OCC) data link resulted from the lack of sync between the camera and the LED signal lamp, as well as the gap time between every two consecutively captured pictures, the fundamental principle of LED-camera based OCC data link, camera parameters like pixel row number, pixel read out time, frame rate and shooting angle are analyzed in detail in this paper. Based on the characteristics of the OCC data link, a new data frame structure is proposed in this paper. When compared to the related data frame structure like interleaved Hamming coding and Raptor coding, the proposed date frame structure has a higher data transmission rate, and has the capability to fix both the inter-frame and intra-frame data loss problems. Numerical and measurement results both prove the validity of the theoretical analysis, finally.关键词：optical camera communication;visible light communication;data frame structure;rolling shutter;data transmission rate;frame loss rate5|14|0更新时间：2025-12-08
- 摘要：Optical vortex beam is a special beam that carries orbital angular momentum (OAM). Optical vortex beams with different OAMs are orthogonal to each other, and it’s numbers are infinite in theory, which can provide a new communication dimension for the optical communication systems. Therefore, it has attracted great attentions of worldwide scholars. With the in-depth investigations of OAM based optical communication technology, various OAM communication systems have been developed rapidly, but people seldom pay attention to the topic of energy-utilization efficiency in OAM based communication systems. This paper focuses on and summarizes energy-utilization efficiencies of OAM’s generation, detection, and the energy-utilization efficiency of whole communication systems in recent typical achievements. And the development trends and prospects for the energy-utilization efficiency of the future systems have been analyzed and prospected.关键词：orbital angular momentum (OAM);communication dimension;optical communication;communication systems;energy-utilization efficiency3|14|1更新时间：2025-12-08
- 摘要：Pointing error in wireless optical communication system has an impact on the geometric attenuation of the received optical power, resulting in a decrease in the received optical power of the system and affecting the performance of the system. In order to accurately analyze the effect of pointing error on the performance of wireless optical communication system, based on the intensity distribution of Gaussian beam, the accurate analytical solution of the geometric attenuation model of received optical power in wireless optical communication system with circular aperture is derived. The influence of pointing error on the geometric attenuation of the system under different parameters is simulated, and the accuracy of the analytical solution is verified and compared with the existing model. The results show that there are errors in using the existing approximate model to calculate the geometric attenuation, and the existing errors cannot be ignored， therefore the model derivation under the circular aperture is more in line with the actual situation. In the point-to-point communication and networking communication of wireless optical communication, it is more accurate to use the Gaussian beam geometric attenuation analytical model under pointing error.关键词：wireless optical communication;Gaussian beam;pointing error;geometric attenuation2|14|2更新时间：2025-12-08
- 摘要：To solve the problem of transceiver interference in the in-band full duplex (IBFD) system, a photonic radio frequency interference cancellation system based on phase modulators is proposed. Two phase modulators are used in a Sagnac loop to realize the modulation of the received signal and the local reference interference signal. Proper polarization control in the optical domain can finally cancel the self-interference signal. Experimental results show that the proposed scheme can achieve a single frequency interference suppression of more than 45 dB and a broadband interference suppression of more than 25 dB. The dynamic range of the system can reach 99.4 dB·Hz2/3.关键词：microwave photonics;self-interference cancellation;phase modulator;Sagnac loop3|17|0更新时间：2025-12-08
- 摘要：The light beam flicker and jitter caused by atmospheric turbulence will cause the point spread function (PSF) on the focal plane of the optical communication receiver to randomly fluctuate and drift, causing the photodetector to fail to effectively cover the signal light field. In order to minimize the bit error rate (BER) of free space optical communication (FSO) system under the limitation of multi-mode Gaussian background light noise field and received optical signal energy efficiency, an adaptive photoelectric array signal processing algorithm suitable for intensity modulation / direct detection (IM / DD) is proposed. In this method, the combined array path method is used to calculate the system BER of different array elements, and the minimum BER is used as the criterion to optimize the received photoelectric array element sequence. The analysis and simulation results show that under the same atmospheric turbulence and background light noise conditions, compared with the existing photoelectric array processing algorithm, the new method can greatly reduce the computational complexity of the system, while the system performance loss can be almost ignored.关键词：free space optical communication;photoelectric array receiving;adaptive array algorithm5|16|0更新时间：2025-12-08
- 摘要：In this paper, a full-duplex radio over fiber system with high linearity is proposed. The system overcomes the influence of the third-order intermodulation distortion and the periodic power fading in the downlink. At the same time, wavelength reuse is used in the uplink, which simplifies the complexity of the base station. A full duplex radio over fiber system with high linearity is realized. The experimental results show that compared with the conventional system based on single Mach Zehnder modulator, the third-order intermodulation distortion in the downlink of the proposed system is obviously suppressed and the influence of fiber dispersion is overcome, the spurious free dynamic range of the system is improved by 17dB, and the constellation and error vector amplitude of broadband RF signal are improved significantly. In addition, the uplink can achieve stable wavelength reuse and modulation transmission.关键词：radio over fiber system;full-duplex;third-order intermodulation distortion;fiber dispersion;wavelength reuse5|20|0更新时间：2025-12-08
- 摘要：In order to manage the inter-cell interference of the visble light communication-wireless fidelity (VLC-WiFi) heterogeneous network effectively, a dynamic carrier allocation method based on user centric access (DCAUCA) was designed in this paper, in which multi-AP cells were constructed for users according to user rates and the differences between user request rate and network service rate of each cell was sorted in descending order for the purpose of allocating carriers to each VLC AP sequentially. Furthermore, a strategy called residual interference suppression based on transmitting power control (RISPC) was proposed to further suppress residual interference. Simulation results show that, compared with the comparison method, the DCAUCA improves system throughput by up to 52.15% and user’s satisfaction by up to 7.10%. Compared with DCAUCA, the RISPC improves system throughput by up to 9.66%.关键词：VLC-WiFi heterogeneous network;inter-cell interference;dynamic carrier allocation;interference management;system throughput2|12|3更新时间：2025-12-08
- 摘要：Nonlinear distortion is identified as a major factor affecting the operating bandwidth and spurious-free dynamic range (SFDR) of radio-over-fiber link. Combining with the RF power ratio, polarization multiplexing and bias control techniques, a multi-channel radio-over-fiber link with high dynamic range and octave-spanning bandwidth is constructed for distributed antenna system (DAS). A model of linearity optimization for the proposed link is developed using a Lagrange multiplier method optimization model, and the best trade-off among RF output power, polarization incident angle and RF power ratio can be obtained. Thus, the optimization of link linearity can be achieved on the premise that the third-order intermodulation distortion (IMD3) and second-order harmonic distortion (HD2) are suppressed simultaneously. The simulated and experimental results show the proposed scheme is effective and feasible.关键词：radio-over-fiber;distributed antenna system;Lagrange multiplier method;linearity optimization4|23|0更新时间：2025-12-08
- 摘要：When the vortex beam carrying orbital angular momentum (OAM) is transmitted in the free space optical communication (FSO) channel, the turbulent medium in which will change the propagation characteristics of the vortex beam, destroy the spiral structure of the wave-front, and ultimately directly affect the stability and reliability of communication. To make up the shortcomings of the previously experimental research in the generalization, a high-power vortex beam array based on coherent beam combining (CBC) technology is selected as the research light source, and a complete system architecture is established from a theoretical point of view to analyze the impact of the amplitude and phase fluctuations caused by atmospheric turbulence on the performance of OAM based FSO communication systems. Applying the optical heterodyne detection (OHD), the random distribution of signal-to-noise ratio (SNR) under turbulent conditions is studied in detail. Based on this, the analytical expression of symbol error probability (SEP) under the condition of Mary Phase-Shift Keying (MPSK) has been derived, and the influence of different turbulence channel parameters, beam parameters and receiver parameters on SEP has been investigated. The results suggest that increasing the beam waist radius of the array sub-beams and the number of the array sub-beams, and reducing the ring radius of the array can improve the beam quality and optimize the system performance. In addition, the smaller topological charge, propagation distance and turbulence intensity, and larger receiver aperture diameter can make the symbol error probability lower and the corresponding communication performance better.关键词：orbital angular momentum;free space optical communication;coherent beam combining;optical heterodyne detection;symbol error probability2|15|1更新时间：2025-12-08
- 摘要：Due to a good trade-off between performance and complexity, a new class of decoding schemes, called soft-aided hard-decision (SA-HD) decoders, has become particularly interesting to optical communication fields in recent years. Soft-aided bit-marking (SABM) algorithm is one of the popular ones. To be friendly for hardware implementation, this paper proposes an improved SABM (iSABM) algorithm for staircase codes (SCCs), which we call iSABM-SCC. With the help of channel soft information, iSABM-SCC marks bits into three types according to their reliabilities using two thresholds. The marked information is then used to assist the staircase decoder to prevent miscorrections and to extend the error-correcting capability, thus improving the performance of SCCs. The simulation results for free-space optical communications show that the proposed iSABM-SCC scheme achieves higher performance gains over standard SCC (S-SCC) and RS code in turbulence channels. For instance, iSABM-SCC with code rate of 0.75 has been shown to yield up to 4.37 dB performance gain when compared to S-SCC for 4-PAM and up to 11.06 dB performance gain when compared to RS code for 8-PAM in a strong turbulence channel.关键词：free space optical communication;forward error correction;staircase code;hard-decision decoder;soft-decision decoder2|16|0更新时间：2025-12-08
- 摘要：For improving the throughput and the fairness of user experience of indoor power line communications-visible light communications (PLC-VLC) system, an improved genetic algorithm based joint user pairing and subcarrier allocation (IGA-JUPSA) method is proposed in the paper. In the user pairing stage, a method of optimal non-orthogonal multiple access (NOMA) user pairing is designed to improve the throughput of PLC-VLC system. During the process of subcarrier allocation, the subcarrier allocation scheme combined NOMA with orthogonal multiple access (OMA) is proposed, and the improved genetic algorithm is used to optimize the subcarrier allocation for different NOMA groups for improving the system throughput and user fairness. Simulation results show that the proposed IGA-JUPSA can improve the throughput of PLC-VLC cascaded system and the fairness experience of users.关键词：PLC-VLC system;NOMA;sub-carrier allocation;improved genetic algorithm;system throughput3|14|1更新时间：2025-12-08
- 摘要：In order to establish an accurate model of the hybrid radio frequency/free space optical(Radio Frequency/Free Space optical, RF/FSO) aviation relay communication system link under the condition of co-channel interference, a multi-user diversity(Multi-User Diversity, MUD) airborne platform RF/FSO hybrid link performance analysis method is proposed. The independent and identically distributed Nakagami-m fading channel is used to characterize the RF user signal and the co-channel interference(Co-Channel Interference, CCI) signal channel, while the FSO link between relay to destination is assumed to be affected by Exponentiated Weibull distributed atmospheric turbulence and the Rayleigh distributed pointing error. The decoding and forwarding protocol is adopted at the relay node to avoid accumulation of noise. Based on the cumulative distribution function of the system's end-to-end equivalent signal-to-noise ratio, the closed expressions for link outage probability and average bit error rate are derived. The research results show that when using coherent binary phase shift keying modulation, the system has the best error performance. The influence of interference signals can be reduced by increasing the number of users.关键词：RF/FSO communication system;multiuser diversity;co-channel interference;exponentiated weibull distribution;average bit error rate;outage probability4|14|2更新时间：2025-12-08
- 摘要：Based on the transmission characteristics of vortex beams and light scattering theory, the field distribution and interference characteristics of superposition vortex beams passing through the rotating random rough surface are studied. Two vortex beams with the same topological charge value and opposite signs are used for simulation and experiment of superimposition generation. Using angular spectrum diffraction theory, the influence of the root-mean-square roughness of the rotating random rough surface on the beam transmission is analyzed. As the superposition vortex beams with different topological charges pass through the rotating random rough surface and interfere with the reference light, the time-dependent curve of normalized intensity values at different rotational speeds can be obtained through numerical calculation. Then the frequency shift can be indirectly obtained by light intensity-time function and the speed of rotating target can be obtained through inversion. The results show that: the frequency is inverted by the period of the simulation curve, and when the rotational speed Ω is 2π/3 rad/s, 2π rad/s, 10π/3 rad/s, the corresponding frequency shift Δf is 2/3Hz, 2Hz, 10/3Hz, respectively. The results of this research can provide a theoretical reference for the regulation and application of superposition vortex beams.关键词：superposition vortex beams;rotating random rough surface;frequency shift;field distribution;interference4|13|0更新时间：2025-12-08
- 摘要：A novel optical transmitting antenna based on free-form lens is proposed for visible light cellular network in order to improve the signal quality in the whole coverage area and communication performance of the system. Based on the energy mapping relation and Snell’s law, the optical transmitting antenna based on free-form lens is designed to realize rectangle light receiving areas. Using this optical transmitting antenna, the light signal from light emitting diodes (LED) source can be distributed uniformly in a square area of 0.8 m × 0.8 m. On this basis, a visible light cellular network with the novel optical transmitting antenna is applied, of which the quality of the receiving light signal and system performance are further investigated. It is demonstrated that in a 3 m × 3 m × 3 m room with 16 LEDs using the designed optical antenna, the uniformity of light distribution in the light network converage reaches 0.8. With the elimination of co-channel interference, the average signal to interference and noise ratio (SINR) is 12.6 dB, which can effectively improve the bit error ratio (BER) and ensure the communication performance of visible light cellular networks.关键词：optical transmitting antenna;visible light cellular network;free-form lens;visible light communications3|15|1更新时间：2025-12-08
OPTICAL WIRELESS COMMUNICATION AND NETWORKING TECHNOLOGY
- 摘要：Recent years have witnessed booming application of Internet of Things to many military and civilian fields (disaster recovery, environmental monitoring, military confrontation, and so on). In practical application, in order to maintain the freshness of terminal data, data aggregation scheduling must be completed with the lowest possible delay, so as to provide users with timely and accurate data services. However, affected by signal interference, the minimum-delay data aggregation scheduling problem has been proved to be NP-hard, and how to design a low-delay data aggregation scheduling algorithm is a hot topic in the field of Internet of Things. Most of existing solutions for traditional Internet of Things (such as wireless sensor networks) usually adopt the layer-by-layer scheduling method and the interference-avoidance technology, which is not conducive to improve data aggregation delay due to the reduced number of concurrent transmission links. It is worth noting that successive interference cancellation (SIC) technology, as a kind of simple and powerful multi-packet receiving technology, is a major breakthrough made by researchers in recent years. How to combine SIC technology to design low-delay data aggregation scheduling algorithms for Internet of Things has very important theoretical research significance. Therefore, this paper utilizes the idea of cross-layer concurrent transmission to schedule the data aggregation process, incorporates the SIC technology to schedule the data aggregation links, and proposes a novel delay-efficient data aggregation scheduling algorithm, with the aim of increasing the number of concurrent transmission links to the most extent. Simulation results show that, our algorithm can improve the data aggregation delay by at most 43.8% compared with the existing algorithm.关键词：successive interference cancellation;cross-layer concurrent transmission;data aggregation scheduling;shortest path tree;Internet of Things2|18|1更新时间：2025-12-08
- 摘要：To improve the recognition accuracy and computational efficiency of gait recognition for lower extremity surface electromyography (sEMG), the Gaussian kernel function-regularized extreme learning machine (GKF-RELM) algorithm is presented. The features of time domain, frequency domain and non-linear dynamics via sEMG signals are extracted and the corresponding gait recognition rates are calculated, respectively. Fisher discriminant function is utilized to analyze the separability of the proposed features, and the fusion features of multi-class features are obtained as the input data to train the classifiers, and the trained classifier is used for gait recognition. The recognition rate and calculation time are compared with support vector machine (SVM) and deep neural network (DNN). The results show that the combination of multi-class features based on Fisher discriminant separability index can obtain the optimal recognition effects, and improve the classification accuracy, as well as optimize the calculation efficiency. In addition, the recognition rate of GKF-RELM method is preferable to that of traditional ELM method.关键词：gait recognition;multi-feature fusion;GKF-RELM algorithm;deep neural network (DNN);Fisher discriminant analysis2|16|0更新时间：2025-12-08
- 摘要：It is the key to improve the performance of graph calculation by improving the efficiency of the graph partitioning algorithm and reducing the communication edge scale between the subgraphs. Due to the limited memory capacity of single computing node, it is difficult to meet the partitioning requirements of large-scale graphs in terms of partitioning efficiency and partitioning quality. In this paper, a distributed graph partitioning algorithm based on hierarchical affinity clustering for massive scale graphs is designed, called DisHAP. It uses the Boruvka minimum spanning tree algorithm to balance cluster the graph under the constraint condition of the input graph according to the vertex similarity, and partitions the graph into k subgraph (partitions) with equal size. In order to optimize the fractiom of edges cut between these large subgraphs, we map the initial partition results to the vertex sequence and cut into a large number of subsections, randomly select the sub slice pairs in the neighbor subgraph sequence, and migrate the vertices according to the mutual exchange and the single vertex positive profit. Thus, the optimization problem of large data volume is converted to a large number of small problems to solve. The algorithm is applied to the MapReduce framework to effectively improve the efficiency of the algorithm. Finally, we use various actual and theoretical graph data to compare with existing graph partitioning algorithms to verify the effectiveness of the DisHAP algorithm. Taking the graph Twitter as an example, it is partitioned into 2,4,8,16,32 partitions. Compared to LDG, BLP, Spinner, Fennel, ParMetis and PSA-MIR algorithms, the fraction of edges cut is reduced by 30.2%, 29.4%, 10.2%, 7.8%, 1.7%, and 3.3% respectively.关键词：distributed large-scale graph partitioning;hierarchical clustering;local optimization;distributed graph computation;balanced partitioning2|14|1更新时间：2025-12-08
- 摘要：To solve the problem of low data quality and high incentive cost caused by the inactivity of participants in mobile crowd sensing, this paper proposes a task recommendation method. We could analyze the participants according to their historical behavior, and filter out low-quality sensing users. Meanwhile, the similarity among the participants was used to build a user-hybrid model. Then, the participants' willingness would be predicted by the probabilistic matrix factorization, and a ranking model was obtained. Finally, a task recommendation list was generated on the basis of ranking model as the preferred task list for the target participants. The simulation experiments based on the real dataset show that the proposed method in this paper can improve the accuracy of task assignment effectively and reduce the moving distance of sensing users simultaneously.关键词：mobile crowd sensing;task recommendation;collaborative ranking;user-hybrid model;participants' willingness2|16|3更新时间：2025-12-08
- 摘要：Oracle-Bone inscriptions are the earliest systematic and mature Chinese characters presently discovered. The study of Oracle-Bone inscriptions is of great significance to historical exploration and cultural inheritance. However, in order to realize character-level Oracle-Bone image annotation, in the existing technical environment, only experienced experts in Oracle-Bone inscriptions can carry out manual annotation, which not only consumes human resources, but also is inefficient. Aiming at this problem, based on the Oracle-Bone image recognition model in the previous work, this paper proposes an automatic annotation algorithm for Oracle-Bone character images. In this algorithm, each character image on the Oracle-Bone rubbings is first reduced to a specific column. Then, the Oracle-Bone character images corresponding to the characters in the original text are found by taking the anchor point as the reference point and according to the nearest neighbor relation of space, so as to realize the automatic labeling of the Oracle-Bone character images.At the same time, the labeled Oracle-Bone images are added to the sample data set, and the original Oracle-Bone character image recognition model is retrained by using the augmented data set（6-10 times increase）, which is conducive to improve the recognition accuracy of the Oracle-Bone character recognition algorithm based on deep learning. In this way, the number of samples can be greatly increased at a small cost, and a lot of time and manpower of experts can be saved.关键词：Oracle-Bone inscriptions; image annotation; data augmentation; anchor point; spatial neighbor; pattern recognition3|16|4更新时间：2025-12-08
- 摘要：Benefiting from large amounts of ground-truths of to-be-segmented scenarios, deep-learning based and supervised foreground segmentation algorithms generally outperform conventional unsupervised methods. However, pixel-wise annotation is a tedious task, especially when it comes to the annotation of foreground moving objects. This seriously limits the deployment of a supervised algorithm in a wide range of scenes without ground-truths. To address the dependence on supervised information of to-be-segmented unseen scenes, we design an inter-frame high-level feature differencing algorithm with a deep learning architecture via integrating the traditional frame differencing method. The proposed algorithm leverages the transfer of cross-scene common knowledge, such as temporal changes, so as to achieve high performance for the scene in the absence of supervised information of to-be-segmented scenes. We evaluate our method on five challenging scenes with different patterns. The average F-Measure of our algorithm is 0.8719, which surpasses the current highest-performance (supervised) algorithm (FgSegNet_v2) under the cross-scene learning condition and the best unsupervised algorithm SemanticBS. Our method which can process a QVGA (320 × 240) video at 35 frames per second shows favorable real-time performance.关键词：foreground segmentation;transfer learning;frame differencing algorithm;cross-scene learning;deep learni2|15|2更新时间：2025-12-08
- 摘要：Audio scene clustering (ASC) is a task to merge audio samples belonging to the same type of acoustic scene into a single cluster. This paper proposes a method of ASC based on joint learning framework. The proposed framework consists of a convolution autoencoder network (CAN) and a discriminative clustering network (DCN). The CAN is used to extract deep transformed feature (DTF), while the DCN is used to do cluster estimation on the input DTF for realizing ASC. Two datasets, DCASE-2017 and LITIS-Rouen, are used as experimental data, and the performance of different features and clustering methods are compared. Experimental results show that the DTF extracted by the joint learning framework outperforms other features, and our method is superior to other methods, in terms of the metrics of both normalized mutual information and clustering accuracy. The cost of the proposed method is the higher computational complexity.关键词：audio scene clustering;joint learning framework;convolutional autoencoder network;discriminative clustering network5|13|0更新时间：2025-12-08
PAPERS
- 摘要：Image caption aims to extract the features of the image and input the description of the final output image into the language generation model, which solves the intersection of natural language processing and computer vision in artificial intelligence-image understanding. Summarize and analyze representative thesis of image description orientation from 2015 to 2020，different core technologies as classification criteria，it can be roughly divided into: image caption based on Encoder-Decoder framework, image caption based on attention mechanism, image caption based on reinforcement learning, image caption based on Generative Adversarial Networks, and based on new fusion data set these five categories. Use three models of NIC, Hard-Attention and Neural Talk to conduct experiments on the real data set MS-COCO data set, and compare the average scores of BLEU1, BLEU2, BLEU3, and BLEU4 to show the effects of the three models. This article points out the development trend of image caption in the future, and the challenges that image caption will face and the research directions that can be digged in.关键词：intelligence-image understanding;encoder-decoder framework;attention mechanism;reinforcement learning7|14|11更新时间：2025-12-08
SURVEYS AND REVIEWS
- 摘要：Based on the theory of charge voltage boost and discharge voltage buck successively for series capacitors, this paper proposes a new type of resonant bidirectional switched capacitor converter. A tiny parameter resonant inductance will comply soft-switching in the whole circuit without any other additional component. The real-time bidirectional power transmission can be implemented without the operation mode change, and the transmission direction only depends on the voltage values at the high and low ends. The mathematical expression of average charging current、 transmitted power、 output voltage and conversion efficiency can be achieved based on the resonance law of RLC circuit and the isoelectric quantity method. Finally, through the MATLAB/Simulink simulation and designed prototype, the validity of the proposal had been verified by the experiments in unidirectional and bidirectional modes.关键词：switched capacitor converter;soft-switching;real-time bidirectional;average current;transmitted power2|14|0更新时间：2025-12-08
- 摘要：With the development of the vehicular network, new radio technologies have been in the spotlight. Communication between vehicles requires both ultra-reliability and low latency, and at the same time has high requirements for communication data rates. The urban scenario of Daejeon, South Korea, is simulated and the characteristics of the vehicular mobile communication channel at 23 GHz are characterized. Typical channel parameters such as path loss, Ricean K-factor, root mean square delay spread, and angle spread are extracted through ray tracing simulation. The influence of parameters on vehicle communication is quantitatively analyzed and summarized, providing reference and guidance suggestions for the design of millimeter wave vehicular mobile communication system.关键词：vehicular mobile communication;millimeter wave channel modeling;ray tracing;urban scenario3|13|2更新时间：2025-12-08
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