Efficient energy utilization in covert communication sustains covertness while assuring communication quality and efficiency.This paper investigates covert communication energy efficiency(EE)in direct uplink satellite...Efficient energy utilization in covert communication sustains covertness while assuring communication quality and efficiency.This paper investigates covert communication energy efficiency(EE)in direct uplink satellite-ground communications,focusing on enhancing system EE via optimized transmit beamforming and satellite orbit altitude selection.This paper first establishes an optimization problem to maximize system EE in a direct uplink satelliteground covert communication scenario.To solve this non-convex optimization problem,it is decomposed into two subproblems and solved using the successive convex approximation(SCA)method.Based on the above methods,this paper proposes an overall iterative optimization algorithm.Simulation results demonstrate that the proposed algorithm surpasses the conventional baseline algorithms in terms of system EE.Furthermore,they elucidate the correlation between the amount of information received by the receiver and the variations in the satellite’s orbital altitude.展开更多
The acquisition of position information of legitimate users and jammers plays an important role in the emerging non-geostationary synchronous orbit(NGSO)satellite communications.In this paper,we study the multi-signal...The acquisition of position information of legitimate users and jammers plays an important role in the emerging non-geostationary synchronous orbit(NGSO)satellite communications.In this paper,we study the multi-signal localization problem in an uplink NGSO satellite communication system.We propose an onboard localization scheme based on multiple observations from the satellite,together with the geometric constraints of the satellite postions,the signal positions,the attitude of the satellite,and the angle-of-arrival(AoAs)of the signals.We develop a massage-passing algorithm,termed the Bayesian blind multi-signal localization(BMSL),to jointly estimate the AoAs and the signal positions.The Cramér-Rao lower bound(CRLB)is derived to characterize the fundamental performance limit of the considered localization problem.Simulation results show that the proposed BMSL algorithm can perform close to the derived CRLB and significantly outperforms its counterpart algorithms.展开更多
In this paper,we analyze the physical layer security(PLS)performance of a free-space optical(FSO)communication system composed of a transmitting satellite and ground users.Specifically,the FSO fading channels follow t...In this paper,we analyze the physical layer security(PLS)performance of a free-space optical(FSO)communication system composed of a transmitting satellite and ground users.Specifically,the FSO fading channels follow the Málaga distribution.Further,we scrutinize the influence of non-zero boresight pointing errors and angle-of-arrival fluctuations on the PLS performance for the first time.We derived the probability density function and cumulative density function of the FSO link,followed by the closed-form expressions of the secrecy outage probability(SOP)and the probability of strictly positive secrecy capacity(SPSC).The asymptotic SOP expression at the high signal-to-noise ratio regime and diversity order are also provided to reveal the physical mechanism of the PLS of the considered system.Finally,Monte Carlo simulation results are presented to verify the correctness of the analytical expressions.The results afford helpful insights for the future design of satellite FSO communication systems.展开更多
This article studies the problem of image segmentation-based semantic communication in autonomous driving.In real traffic scenes,the detecting of objects(e.g.,vehicles and pedestrians)is more important to guarantee dr...This article studies the problem of image segmentation-based semantic communication in autonomous driving.In real traffic scenes,the detecting of objects(e.g.,vehicles and pedestrians)is more important to guarantee driving safety,which is always ignored in existing works.Therefore,we propose a vehicular image segmentation-oriented semantic communication system,termed VIS-SemCom,focusing on transmitting and recovering image semantic features of high-important objects to reduce transmission redundancy.First,we develop a semantic codec based on Swin Transformer architecture,which expands the perceptual field thus improving the segmentation accuracy.To highlight the important objects'accuracy,we propose a multi-scale semantic extraction method by assigning the number of Swin Transformer blocks for diverse resolution semantic features.Also,an importance-aware loss incorporating important levels is devised,and an online hard example mining(OHEM)strategy is proposed to handle small sample issues in the dataset.Finally,experimental results demonstrate that the proposed VIS-SemCom can achieve a significant mean intersection over union(mIoU)performance in the SNR regions,a reduction of transmitted data volume by about 60%at 60%mIoU,and improve the segmentation accuracy of important objects,compared to baseline image communication.展开更多
To tackle the physical layer security challenges in wireless communication,this paper introduces a multiuser architecture that leverages single-channel blind source separation,centered around a Multi-source Signal Mix...To tackle the physical layer security challenges in wireless communication,this paper introduces a multiuser architecture that leverages single-channel blind source separation,centered around a Multi-source Signal Mixture Separator(MSMS).This architecture consists of a multi-user encoder,a channel layer,and a separation decoder,allowing it to handle multiple functions simultaneously,including encoding,modulation,signal separation,demodulation,and decoding.The MSMS receiver effectively enables the separation of numerous user signals,making it exceedingly difficult for unauthorized eavesdroppers to extract valuable information from the mixed signals,thus significantly enhancing communication security.The MSMS can address the challenges of few-shot sample training and achieve joint optimization during transmission by employing a deep learning-based network design.The design of a single receiver reduces system costs and improves spectrum efficiency.The MSMS outperforms traditional Space-time Block Coding(STBC)strategies regarding separation performance,particularly in Block Error Rate(BLER)metrics.Modulation constellation diagrams further analyze the effectiveness of multi-source signal mixture separation.Moreover,this study extends the MSMS framework from a two-user scenario to a three-user scenario,further demonstrating the flexibility and scalability of the proposed architecture.展开更多
This paper presents an image encryption scheme for underwater optical wireless communication(UOWC)systems based on dynamically generated hyperchaotic S-boxes,aiming to enhance both data security and transmission perfo...This paper presents an image encryption scheme for underwater optical wireless communication(UOWC)systems based on dynamically generated hyperchaotic S-boxes,aiming to enhance both data security and transmission performance in underwater environments.The proposed encryption approach provides strong confusion and diffusion properties and is evaluated over five Jerlov water types with different optical attenuation characteristics.Security analysis demonstrates that the encrypted images achieve information entropy values close to the ideal value of 8(7.9925–7.9993),with very low correlation coefficients in horizontal,vertical,and diagonal directions,as well as the system achieves high values in key metrics such as the Unified Average Changing Intensity(UACI)and Number of Pixel Change Rate(NPCR),ranging from 33.42 to 33.47 and from 99.58%to 99.62%,respectively,both near their theoretical optima.In addition to improving confidentiality,the hyperchaotic encryption process decorrelates pixel intensities and redistributes image spectral content,which enhances robustness against underwater absorption and scattering effects.As a result,improved transmission performance is observed;for example,in Jerlov type I(JI)water,the effective transmission distance is extended from16mfor plain images to 24mfor encrypted images,while the Peak Signal to Noise Ratio(PSNR)at 24 m increases from 9.25 to 20.13 dB after decryption and enhancement.These results confirmthat the proposed scheme provides a dual benefit of secure and reliable image transmission in UOWC systems.展开更多
The smart meter communication system has substantial application value for the construction and upgrading of the entire power system.The deployment of the transmitter(Tx)of the smart meter system in the residential sc...The smart meter communication system has substantial application value for the construction and upgrading of the entire power system.The deployment of the transmitter(Tx)of the smart meter system in the residential scenarios is vexed by the need for more theoretical support.This paper mainly studies the communication channel between the Tx at semibasement and receiver(Rx)at outdoor.The design of an effective communication system relies on an accurate understanding of channel characteristics.Channel measurements and ray-tracing channel modeling are conducted to obtain channel data.The influence of different positions at same semi-basement is studied.Typical channel characteristics are analyzed,such as power delay profile(PDP),power angular profile(PAP),root-mean-square(RMS)delay spread(DS),channel capacity,received power,and path loss.The influence of different semi-basement placements and different floor heights is also compared.Besides,the channel measurements and simulation data fit well,which can illustrate the validity and reliability of the acquired channel data.This paper can provide theoretical support for the design and optimization of smart meter communication systems in semi-basement scenarios.展开更多
1.Introduction From the first-generation(1G)through the second-generation(2G)Global System for Mobile Communications(GSM),the third-generation(3G)wideband code division multiple access(WCDMA)to the fourth-generation(4...1.Introduction From the first-generation(1G)through the second-generation(2G)Global System for Mobile Communications(GSM),the third-generation(3G)wideband code division multiple access(WCDMA)to the fourth-generation(4G)long-term evolution(LTE)wireless networks,terrestrial networks(TNs)have demonstrated significant success in increasing communication speeds and improving quality of service(QoS)for users.展开更多
BACKGROUND Child vaccination plays a great role in preventing infectious diseases in children.While Ethiopia has emphasized child vaccination,its effectiveness largely depends on efficient communication between health...BACKGROUND Child vaccination plays a great role in preventing infectious diseases in children.While Ethiopia has emphasized child vaccination,its effectiveness largely depends on efficient communication between health practitioners and mothers/caregivers.Thus,sufficient communication contributes to promoting child immunization and in turn improving child health.AIM To examine child vaccine communication practices and strategies as well as their relationship with sociodemographic characteristics of respondents in the Amhara region of Ethiopia.METHODS A quantitative cross-sectional survey was conducted using a pretested Likert scale questionnaire and distributed to 123 health workers in primary healthcare centers between April 2024 and June 2024.The data were analyzed using both descriptive and inferential statistics.RESULTS The results indicated that the most common vaccine communication activities included education and communication(mean score=24.1),vaccine data registration(mean score=8.86),and information exchange(mean score=8.3).A significant correlation was found between the implementation of interpersonal health communication principles and immunization communication training(F=341.756,P=0.000,P<0.05).However,no significant correlations were observed between age,education,work experience,and vaccine communication practices.Additionally,the study found that the application of interpersonal communication principles was associated with the perceived relevance of immunization communication(F=27.790,P=0.000,P<0.05).CONCLUSION Based on the findings the study concluded that communication practice in promoting child immunization is insufficient.To enhance vaccine acceptance,continuous immunization communication training for health workers is recommended.展开更多
Frequency hopping(FH)communication has good anti-fading,anti-jamming and anti-eavesdropping capabilities,so it is one of the main ways to combat electronic jamming.In order to further improve the anti-jamming capabili...Frequency hopping(FH)communication has good anti-fading,anti-jamming and anti-eavesdropping capabilities,so it is one of the main ways to combat electronic jamming.In order to further improve the anti-jamming capability of FH communication,the parameters such as fixed frequency interval,hopping rate and hopping frequency in conventional FH can be assigned with time-varying characteristics.In order to set appropriate hopping parameters to improve the performance of the system in the electromagnetic environment with various types of jamming,a heuristically accelerated Q-learning(HAQL)method is proposed in this paper.Firstly,a theoretical model for the parameter decision-making of FH system is made,and the key parameters affecting the energy efficiency of the system are analyzed.Secondly,a Q-learning model in complex electromagnetic environment is proposed,which includes setting states,actions and rewards,as well as a HAQL-based decisionmaking algorithm is put forward.Lastly,simulations are carried out under different jamming environments,and simulation results show that the average energy efficiency of HAQL algorithm is higher than that of the SARSA algorithm,the e-greedy QL algorithm and the HQL-OSGM algorithm,respectively.展开更多
Delay Alignment Modulation(DAM)is an innovative broadband modulation technique well-suited for millimeter Wave(mm Wave)and Terahertz(THz)massive Multiple-Input Multiple-Output(MIMO)communication systems.Leveraging the...Delay Alignment Modulation(DAM)is an innovative broadband modulation technique well-suited for millimeter Wave(mm Wave)and Terahertz(THz)massive Multiple-Input Multiple-Output(MIMO)communication systems.Leveraging the high spatial resolution and sparsity of multi-path channels,DAM effectively mitigates Inter-Symbol Interference(ISI)by aligning all multi-path components through a combination of delay pre-compensation(or post-compensation)and path-based beamforming.As such,ISI is eliminated while preserving multi-path power gains.In this paper,we investigate multi-user double-side DAM,which incorporates both delay pre-compensation at the transmitter and post-compensation at the receiver,in contrast to prior works that primarily focus on singleside DAM with only delay pre-compensation.Firstly,we derive the constraint on the number of introduced delays and formulate the corresponding delay pre/post-compensation vectors tailored for multi-user double-side DAM,given a specific number of delay compensations.Furthermore,we demonstrate that when the number of Base Stations(BSs)/User Equipment(UE)antennas is sufficiently large,single-side DAM—where delay compensation is performed only at the BS/UE—is preferable to double-side DAM,since the former results in less ISI to be spatially eliminated.Next,we propose two low-complexity path-based beamforming strategies based on the eigen-beamforming transmission and ISI-Zero Forcing(ZF),respectively.On this basis,we further analyze the achievable sum rates.Simulation results verify that with a sufficiently large number of BS/UE antennas,singleside DAM is adequate for ISI elimination.Moreover,compared to the benchmarking scheme of Orthogonal Frequency Division Multiplexing(OFDM),multi-user BS-side DAM achieves higher spectral efficiency and lower Peak-to-Average Power Ratio(PAPR).展开更多
Reconfigurable intelligent surfaces(RISs)not only assist communication but also help the localization of user equipment(UE).This study focuses on indoor localization of UE with a single access point(AP)and multiple RI...Reconfigurable intelligent surfaces(RISs)not only assist communication but also help the localization of user equipment(UE).This study focuses on indoor localization of UE with a single access point(AP)and multiple RISs.First,we propose a two-stage channel estimation scheme where RIS phase shifts are tuned to obtain multiple channel soundings.In the first stage,the newtonized orthogonal matching pursuit algorithm extracts the parameters of multiple paths from the received signals.Then,the LOS path and RISreflected paths are identified.In the second stage,the estimated path gains of RIS-reflected paths with different phase shifts are utilized to determine the angle of arrival(AOA)at the RIS by obtaining the angular pseudo spectrum.Consequently,by taking the AP and RISs as reference points,the linear least squares estimator can locate UE with the estimated AOAs.Simulation results show that the proposed algorithm can realize centimeter-level localization accuracy in the discussed scenarios.Moreover,the higher accuracy of pseudo spectrum,a larger number of channel soundings,and a larger number of reference points can realize higher localization accuracy of UE.展开更多
The radio frequency(RF)fingerprint technique is a robust method for security enhancement of the physical layer by leveraging the unique RF imperfections inherent in various wireless devices.Among these imperfections,t...The radio frequency(RF)fingerprint technique is a robust method for security enhancement of the physical layer by leveraging the unique RF imperfections inherent in various wireless devices.Among these imperfections,the carrier frequency offset(CFO)stands out as a primary RF fingerprint(RFF)of the transmitter,offering the potential to distinguish among different transmitters.However,accurately estimating CFO in time-varying channels poses significant challenges due to multipath effects and Doppler shifts.In this paper,we focus on estimating CFO for wireless device identification in the orthogonal frequency division multiplexing(OFDM)communication system.To achieve precise CFO estimation under time-varying channels,we propose a frequency domain correlation and spline interpolation(FCSI)algorithm.This approach utilizes pilots distributed across different subcarriers to correlate with prior local sequences,facilitating accurate CFO estimation.Classification is then performed based on the Euclidean distance between the prior RFF and the tested RFF dataset.Simulation results demonstrate that the proposed Mconsecutive average method effectively reduces the classification error rate in the challenging high-frequency(HF)skywave channel environment.展开更多
Recently,unmanned aerial vehicle(UAV)-aided free-space optical(FSO)communication has attracted widespread attentions.However,most of the existing research focuses on communication performance only.The authors investig...Recently,unmanned aerial vehicle(UAV)-aided free-space optical(FSO)communication has attracted widespread attentions.However,most of the existing research focuses on communication performance only.The authors investigate the integrated scheduling of communication,sensing,and control for UAV-aided FSO communication systems.Initially,a sensing-control model is established via the control theory.Moreover,an FSO communication channel model is established by considering the effects of atmospheric loss,atmospheric turbulence,geometrical loss,and angle-of-arrival fluctuation.Then,the relationship between the motion control of the UAV and radial displacement is obtained to link the control aspect and communication aspect.Assuming that the base station has instantaneous channel state information(CSI)or statistical CSI,the thresholds of the sensing-control pattern activation are designed,respectively.Finally,an integrated scheduling scheme for performing communication,sensing,and control is proposed.Numerical results indicate that,compared with conventional time-triggered scheme,the proposed integrated scheduling scheme obtains comparable communication and control performance,but reduces the sensing consumed power by 52.46%.展开更多
Digital infrastructure possesses dual attributes as both an international public good and a strategic communication tool for major countries. In recent years, the US has been active in the field of global digital infr...Digital infrastructure possesses dual attributes as both an international public good and a strategic communication tool for major countries. In recent years, the US has been active in the field of global digital infrastructure, showing a trend of deep coupling and mutual embedding with strategic communication. The US has built a strategic communication system for digital infrastructure. This system is designed to set the international agenda, collect information and intelligence, and deter its competitors. The system presents a three-way coherent infrastructure of a basic layer, application layer,and value layer. The mode of operation is characterized by commercial force collaboration, alliance system linkage, and global multi-domain network layout. However, to maintain its unipolar digital hegemony,the United States has over-instrumentalized its digital infrastructure and exploited and amplified the asymmetry of digital science and technology for a long period of time, which not only highlights its unilateral stance and exclusionary nature but also results in a global digital divide and trust deficit, which will pose constraints on its sustainability in the long term.展开更多
Low earth orbit(LEO)satellite communication which can provide global wireless ser-vice plays a critical role in the future wireless communication networks.However,due to the high speed of satellite motion,numerous nar...Low earth orbit(LEO)satellite communication which can provide global wireless ser-vice plays a critical role in the future wireless communication networks.However,due to the high speed of satellite motion,numerous narrow beams,and complex satellite-terrestrial channels,the initial access between the LEO satellites and user terminals(UEs)becomes more complicated.To establish a stable link,a beam search is required between the satellite and the UE.However,tradi-tional beam search methods(e.g.,exhaustive search)have high time complexity which is not suit-able in high-speed scenarios.Therefore,in this paper,a sensing-aided hierarchical beam search method is proposed,which is performed in two stages.In the first stage,wide beam scanning is per-formed to find the optimal angular range.In the second stage,after determining the directions of narrow beams via sensing the direction of arrival(DOA)of satellite signals,the narrow beams gen-erated at estimated directions are used to sweep the satellite beams.This method can help fast beam alignment and obtain high beam search accuracy,which is verified by simulation results.Moreover,we analyze the gain of beam alignment from the two-stage beam search method.展开更多
High-Frequency(HF)communication is widely used for long-distance transmission in remote and disaster areas.However,the dynamic nature of the ionosphere and multipath propagation in the HF channel pose significant chal...High-Frequency(HF)communication is widely used for long-distance transmission in remote and disaster areas.However,the dynamic nature of the ionosphere and multipath propagation in the HF channel pose significant challenges to designing efficient and robust communication systems.In this paper,we propose a Fixed Station(FS)and frequency matching method,as well as a power allocation method,to improve the sum-rate of air-to-ground HF communication networks.We derive optimal power allocation among users that share the same frequency,based on which a modified water-filling algorithm is used to solve the power allocation problem in multi-user scenarios,while a low-complexity algorithm is proposed to solve the integer optimization problem of frequency-FS matching.Simulation results demonstrate that the proposed algorithm outperforms the naive algorithm,indicating its effectiveness.展开更多
In this work,we consider an Unmanned Aerial Vehicle(UAV)-aided covert transmission network,which adopts the uplink transmission of Communication Nodes(CNs)as a cover to facilitate covert transmission to a Primary Comm...In this work,we consider an Unmanned Aerial Vehicle(UAV)-aided covert transmission network,which adopts the uplink transmission of Communication Nodes(CNs)as a cover to facilitate covert transmission to a Primary Communication Node(PCN).Specifically,all nodes transmit to the UAV exploiting uplink non-Orthogonal Multiple Access(NOMA),while the UAV performs covert transmission to the PCN at the same frequency.To minimize the average age of covert information,we formulate a joint optimization problem of UAV trajectory and power allocation designing subject to multi-dimensional constraints including covertness demand,communication quality requirement,maximum flying speed,and the maximum available resources.To address this problem,we embed Signomial Programming(SP)into Deep Reinforcement Learning(DRL)and propose a DRL framework capable of handling the constrained Markov decision processes,named SP embedded Soft Actor-Critic(SSAC).By adopting SSAC,we achieve the joint optimization of UAV trajectory and power allocation.Our simulations show the optimized UAV trajectory and verify the superiority of SSAC compared with various existing baseline schemes.The results of this study suggest that by maintaining appropriate distances from both the PCN and CNs,one can effectively enhance the performance of covert communication by reducing the detection probability of the CNs.展开更多
In this paper,we investigate an reconfigurable intelligent surface-aided Integrated Sensing And Communication(ISAC)system.Our objective is to maximize the achievable sum rate of the multi-antenna communication users t...In this paper,we investigate an reconfigurable intelligent surface-aided Integrated Sensing And Communication(ISAC)system.Our objective is to maximize the achievable sum rate of the multi-antenna communication users through the joint active and passive beamforming.Specifically,the weighted minimum mean-square error method is first used to reformulate the original problem into an equivalent one.Then,we utilize an alternating optimization algorithm to decouple the optimization variables and decompose this challenging problem into two subproblems.Given reflecting coefficients,a penalty-based algorithm is utilized to deal with the non-convex radar Signal-to-Noise Ratio(SNR)constraints.For the given beamforming matrix of the base station,we apply majorization-minimization to transform the problem into a Quadratic Constraint Quadratic Programming(QCQP)problem,which is ultimately solved using a Semi-Definite Relaxation(SDR)based algorithm.Simulation results illustrate the advantage of deploying reconfigurable intelligent surface in the considered multi-user MultipleInput Multiple-Output(MIMO)ISAC systems.展开更多
In recent years,intensified environmental pollution and climate change have increasingly exposed the world to natural disasters such as earthquakes and floods,resulting in substantial economic losses[1].These disaster...In recent years,intensified environmental pollution and climate change have increasingly exposed the world to natural disasters such as earthquakes and floods,resulting in substantial economic losses[1].These disasters frequently damage terrestrial communication infrastructures,making the rapid deployment of emergency communication networks in affected areas critical in increasing rescue efficiency[2].展开更多
基金supported in part by the National Natural Science Foundation of China under Grants 62025110,62271093sponsored by Natural Science Foundation of Chongqing,China,under Grant CSTB2023NSCQ-LZX0108.
文摘Efficient energy utilization in covert communication sustains covertness while assuring communication quality and efficiency.This paper investigates covert communication energy efficiency(EE)in direct uplink satellite-ground communications,focusing on enhancing system EE via optimized transmit beamforming and satellite orbit altitude selection.This paper first establishes an optimization problem to maximize system EE in a direct uplink satelliteground covert communication scenario.To solve this non-convex optimization problem,it is decomposed into two subproblems and solved using the successive convex approximation(SCA)method.Based on the above methods,this paper proposes an overall iterative optimization algorithm.Simulation results demonstrate that the proposed algorithm surpasses the conventional baseline algorithms in terms of system EE.Furthermore,they elucidate the correlation between the amount of information received by the receiver and the variations in the satellite’s orbital altitude.
基金National Key R&D Program of China under Grants 2021YFB2900404the National Natural Science Foundation of China under Grants 62371098。
文摘The acquisition of position information of legitimate users and jammers plays an important role in the emerging non-geostationary synchronous orbit(NGSO)satellite communications.In this paper,we study the multi-signal localization problem in an uplink NGSO satellite communication system.We propose an onboard localization scheme based on multiple observations from the satellite,together with the geometric constraints of the satellite postions,the signal positions,the attitude of the satellite,and the angle-of-arrival(AoAs)of the signals.We develop a massage-passing algorithm,termed the Bayesian blind multi-signal localization(BMSL),to jointly estimate the AoAs and the signal positions.The Cramér-Rao lower bound(CRLB)is derived to characterize the fundamental performance limit of the considered localization problem.Simulation results show that the proposed BMSL algorithm can perform close to the derived CRLB and significantly outperforms its counterpart algorithms.
基金National Natural Science Foundation of China(Grant No.62271202,62027802)Zhejiang Provincial Natural Science Foundation of China(Grant No.LZ25F010004)。
文摘In this paper,we analyze the physical layer security(PLS)performance of a free-space optical(FSO)communication system composed of a transmitting satellite and ground users.Specifically,the FSO fading channels follow the Málaga distribution.Further,we scrutinize the influence of non-zero boresight pointing errors and angle-of-arrival fluctuations on the PLS performance for the first time.We derived the probability density function and cumulative density function of the FSO link,followed by the closed-form expressions of the secrecy outage probability(SOP)and the probability of strictly positive secrecy capacity(SPSC).The asymptotic SOP expression at the high signal-to-noise ratio regime and diversity order are also provided to reveal the physical mechanism of the PLS of the considered system.Finally,Monte Carlo simulation results are presented to verify the correctness of the analytical expressions.The results afford helpful insights for the future design of satellite FSO communication systems.
基金National Natural Science Foundation of China under Grants No.62171047,U22B2001,62271065,62001051Beijing Natural Science Foundation under Grant L223027BUPT Excellent Ph.D Students Foundation under Grants CX2021114。
文摘This article studies the problem of image segmentation-based semantic communication in autonomous driving.In real traffic scenes,the detecting of objects(e.g.,vehicles and pedestrians)is more important to guarantee driving safety,which is always ignored in existing works.Therefore,we propose a vehicular image segmentation-oriented semantic communication system,termed VIS-SemCom,focusing on transmitting and recovering image semantic features of high-important objects to reduce transmission redundancy.First,we develop a semantic codec based on Swin Transformer architecture,which expands the perceptual field thus improving the segmentation accuracy.To highlight the important objects'accuracy,we propose a multi-scale semantic extraction method by assigning the number of Swin Transformer blocks for diverse resolution semantic features.Also,an importance-aware loss incorporating important levels is devised,and an online hard example mining(OHEM)strategy is proposed to handle small sample issues in the dataset.Finally,experimental results demonstrate that the proposed VIS-SemCom can achieve a significant mean intersection over union(mIoU)performance in the SNR regions,a reduction of transmitted data volume by about 60%at 60%mIoU,and improve the segmentation accuracy of important objects,compared to baseline image communication.
基金supported by the National Social Science Foundation of China under Grant 2022-SKJJ-B-112。
文摘To tackle the physical layer security challenges in wireless communication,this paper introduces a multiuser architecture that leverages single-channel blind source separation,centered around a Multi-source Signal Mixture Separator(MSMS).This architecture consists of a multi-user encoder,a channel layer,and a separation decoder,allowing it to handle multiple functions simultaneously,including encoding,modulation,signal separation,demodulation,and decoding.The MSMS receiver effectively enables the separation of numerous user signals,making it exceedingly difficult for unauthorized eavesdroppers to extract valuable information from the mixed signals,thus significantly enhancing communication security.The MSMS can address the challenges of few-shot sample training and achieve joint optimization during transmission by employing a deep learning-based network design.The design of a single receiver reduces system costs and improves spectrum efficiency.The MSMS outperforms traditional Space-time Block Coding(STBC)strategies regarding separation performance,particularly in Block Error Rate(BLER)metrics.Modulation constellation diagrams further analyze the effectiveness of multi-source signal mixture separation.Moreover,this study extends the MSMS framework from a two-user scenario to a three-user scenario,further demonstrating the flexibility and scalability of the proposed architecture.
基金funded by Prince Sattam bin Abdulaziz University,grant number PSAU/2025/01/34620.
文摘This paper presents an image encryption scheme for underwater optical wireless communication(UOWC)systems based on dynamically generated hyperchaotic S-boxes,aiming to enhance both data security and transmission performance in underwater environments.The proposed encryption approach provides strong confusion and diffusion properties and is evaluated over five Jerlov water types with different optical attenuation characteristics.Security analysis demonstrates that the encrypted images achieve information entropy values close to the ideal value of 8(7.9925–7.9993),with very low correlation coefficients in horizontal,vertical,and diagonal directions,as well as the system achieves high values in key metrics such as the Unified Average Changing Intensity(UACI)and Number of Pixel Change Rate(NPCR),ranging from 33.42 to 33.47 and from 99.58%to 99.62%,respectively,both near their theoretical optima.In addition to improving confidentiality,the hyperchaotic encryption process decorrelates pixel intensities and redistributes image spectral content,which enhances robustness against underwater absorption and scattering effects.As a result,improved transmission performance is observed;for example,in Jerlov type I(JI)water,the effective transmission distance is extended from16mfor plain images to 24mfor encrypted images,while the Peak Signal to Noise Ratio(PSNR)at 24 m increases from 9.25 to 20.13 dB after decryption and enhancement.These results confirmthat the proposed scheme provides a dual benefit of secure and reliable image transmission in UOWC systems.
基金supported by the Natural Science Foundation of Shandong Province under Grant ZR2024MF062the open research fund of National Mobile Communications Research Laboratory,Southeast University under Grants 2025D03+1 种基金the Future Plan Program for Young Scholars of Shandong University,and the Innovation and Technology Support Program for Young Scholars of Colleges and Universities in Shandong Province under Grant 2022KJ009The B6G R&D Group in Shandong University is greatly thanked for channel measurements.
文摘The smart meter communication system has substantial application value for the construction and upgrading of the entire power system.The deployment of the transmitter(Tx)of the smart meter system in the residential scenarios is vexed by the need for more theoretical support.This paper mainly studies the communication channel between the Tx at semibasement and receiver(Rx)at outdoor.The design of an effective communication system relies on an accurate understanding of channel characteristics.Channel measurements and ray-tracing channel modeling are conducted to obtain channel data.The influence of different positions at same semi-basement is studied.Typical channel characteristics are analyzed,such as power delay profile(PDP),power angular profile(PAP),root-mean-square(RMS)delay spread(DS),channel capacity,received power,and path loss.The influence of different semi-basement placements and different floor heights is also compared.Besides,the channel measurements and simulation data fit well,which can illustrate the validity and reliability of the acquired channel data.This paper can provide theoretical support for the design and optimization of smart meter communication systems in semi-basement scenarios.
基金support from the Development Program from Institute for Communication Systems(ICS),the 5G&6G Innovation Centre(5GIC&6GIC)at University of Surreythe China Scholarship Council,the National Natural Science Foundation of China(62371158)the Major Key Project of Pengcheng Laboratory(PCL2024A01).
文摘1.Introduction From the first-generation(1G)through the second-generation(2G)Global System for Mobile Communications(GSM),the third-generation(3G)wideband code division multiple access(WCDMA)to the fourth-generation(4G)long-term evolution(LTE)wireless networks,terrestrial networks(TNs)have demonstrated significant success in increasing communication speeds and improving quality of service(QoS)for users.
文摘BACKGROUND Child vaccination plays a great role in preventing infectious diseases in children.While Ethiopia has emphasized child vaccination,its effectiveness largely depends on efficient communication between health practitioners and mothers/caregivers.Thus,sufficient communication contributes to promoting child immunization and in turn improving child health.AIM To examine child vaccine communication practices and strategies as well as their relationship with sociodemographic characteristics of respondents in the Amhara region of Ethiopia.METHODS A quantitative cross-sectional survey was conducted using a pretested Likert scale questionnaire and distributed to 123 health workers in primary healthcare centers between April 2024 and June 2024.The data were analyzed using both descriptive and inferential statistics.RESULTS The results indicated that the most common vaccine communication activities included education and communication(mean score=24.1),vaccine data registration(mean score=8.86),and information exchange(mean score=8.3).A significant correlation was found between the implementation of interpersonal health communication principles and immunization communication training(F=341.756,P=0.000,P<0.05).However,no significant correlations were observed between age,education,work experience,and vaccine communication practices.Additionally,the study found that the application of interpersonal communication principles was associated with the perceived relevance of immunization communication(F=27.790,P=0.000,P<0.05).CONCLUSION Based on the findings the study concluded that communication practice in promoting child immunization is insufficient.To enhance vaccine acceptance,continuous immunization communication training for health workers is recommended.
基金State Key Program of National Natural Science of China under grant nos.U19B2016。
文摘Frequency hopping(FH)communication has good anti-fading,anti-jamming and anti-eavesdropping capabilities,so it is one of the main ways to combat electronic jamming.In order to further improve the anti-jamming capability of FH communication,the parameters such as fixed frequency interval,hopping rate and hopping frequency in conventional FH can be assigned with time-varying characteristics.In order to set appropriate hopping parameters to improve the performance of the system in the electromagnetic environment with various types of jamming,a heuristically accelerated Q-learning(HAQL)method is proposed in this paper.Firstly,a theoretical model for the parameter decision-making of FH system is made,and the key parameters affecting the energy efficiency of the system are analyzed.Secondly,a Q-learning model in complex electromagnetic environment is proposed,which includes setting states,actions and rewards,as well as a HAQL-based decisionmaking algorithm is put forward.Lastly,simulations are carried out under different jamming environments,and simulation results show that the average energy efficiency of HAQL algorithm is higher than that of the SARSA algorithm,the e-greedy QL algorithm and the HQL-OSGM algorithm,respectively.
基金supported in part by the Natural Science Foundation for Distinguished Young Scholars of Jiangsu Province under Grant BK20240070in part by the National Natural Science Foundation of China under Grant 62071114n part by the Fundamental Research Funds for the Central Universities under Grant 2242022k60004。
文摘Delay Alignment Modulation(DAM)is an innovative broadband modulation technique well-suited for millimeter Wave(mm Wave)and Terahertz(THz)massive Multiple-Input Multiple-Output(MIMO)communication systems.Leveraging the high spatial resolution and sparsity of multi-path channels,DAM effectively mitigates Inter-Symbol Interference(ISI)by aligning all multi-path components through a combination of delay pre-compensation(or post-compensation)and path-based beamforming.As such,ISI is eliminated while preserving multi-path power gains.In this paper,we investigate multi-user double-side DAM,which incorporates both delay pre-compensation at the transmitter and post-compensation at the receiver,in contrast to prior works that primarily focus on singleside DAM with only delay pre-compensation.Firstly,we derive the constraint on the number of introduced delays and formulate the corresponding delay pre/post-compensation vectors tailored for multi-user double-side DAM,given a specific number of delay compensations.Furthermore,we demonstrate that when the number of Base Stations(BSs)/User Equipment(UE)antennas is sufficiently large,single-side DAM—where delay compensation is performed only at the BS/UE—is preferable to double-side DAM,since the former results in less ISI to be spatially eliminated.Next,we propose two low-complexity path-based beamforming strategies based on the eigen-beamforming transmission and ISI-Zero Forcing(ZF),respectively.On this basis,we further analyze the achievable sum rates.Simulation results verify that with a sufficiently large number of BS/UE antennas,singleside DAM is adequate for ISI elimination.Moreover,compared to the benchmarking scheme of Orthogonal Frequency Division Multiplexing(OFDM),multi-user BS-side DAM achieves higher spectral efficiency and lower Peak-to-Average Power Ratio(PAPR).
基金supported in part by the Fundamental Research Funds for the Central Universities under Grant 2242022k60004in part by the National Natural Science Foundation of China(NSFC)under Grants 62261160576,624B2036,W2421087,62422105+1 种基金in part by the Young Elite Scientists Sponsorship Program by CAST 2022QNRC001,and the“Zhishan”Scholars Programs of Southeast Universityin part by the Key Technologies R&D Program of Jiangsu(Prospective and Key Technologies for Industry)under Grants BE2023022,BE2023022-1 and BE2023022-2.
文摘Reconfigurable intelligent surfaces(RISs)not only assist communication but also help the localization of user equipment(UE).This study focuses on indoor localization of UE with a single access point(AP)and multiple RISs.First,we propose a two-stage channel estimation scheme where RIS phase shifts are tuned to obtain multiple channel soundings.In the first stage,the newtonized orthogonal matching pursuit algorithm extracts the parameters of multiple paths from the received signals.Then,the LOS path and RISreflected paths are identified.In the second stage,the estimated path gains of RIS-reflected paths with different phase shifts are utilized to determine the angle of arrival(AOA)at the RIS by obtaining the angular pseudo spectrum.Consequently,by taking the AP and RISs as reference points,the linear least squares estimator can locate UE with the estimated AOAs.Simulation results show that the proposed algorithm can realize centimeter-level localization accuracy in the discussed scenarios.Moreover,the higher accuracy of pseudo spectrum,a larger number of channel soundings,and a larger number of reference points can realize higher localization accuracy of UE.
基金supported by ZTE Industry-University-Institute Cooperation Funds under Grant No.IA20240723011National Natural Science Foundation of China under Grant No.62371123+1 种基金Young Elite Scientists Sponsorship Program of the Beijing High Innovation Plan under Grant No.20251077Research Fund of National Mobile Communications Research Laboratory,Southeast University under Grant No.2023A03。
文摘The radio frequency(RF)fingerprint technique is a robust method for security enhancement of the physical layer by leveraging the unique RF imperfections inherent in various wireless devices.Among these imperfections,the carrier frequency offset(CFO)stands out as a primary RF fingerprint(RFF)of the transmitter,offering the potential to distinguish among different transmitters.However,accurately estimating CFO in time-varying channels poses significant challenges due to multipath effects and Doppler shifts.In this paper,we focus on estimating CFO for wireless device identification in the orthogonal frequency division multiplexing(OFDM)communication system.To achieve precise CFO estimation under time-varying channels,we propose a frequency domain correlation and spline interpolation(FCSI)algorithm.This approach utilizes pilots distributed across different subcarriers to correlate with prior local sequences,facilitating accurate CFO estimation.Classification is then performed based on the Euclidean distance between the prior RFF and the tested RFF dataset.Simulation results demonstrate that the proposed Mconsecutive average method effectively reduces the classification error rate in the challenging high-frequency(HF)skywave channel environment.
文摘Recently,unmanned aerial vehicle(UAV)-aided free-space optical(FSO)communication has attracted widespread attentions.However,most of the existing research focuses on communication performance only.The authors investigate the integrated scheduling of communication,sensing,and control for UAV-aided FSO communication systems.Initially,a sensing-control model is established via the control theory.Moreover,an FSO communication channel model is established by considering the effects of atmospheric loss,atmospheric turbulence,geometrical loss,and angle-of-arrival fluctuation.Then,the relationship between the motion control of the UAV and radial displacement is obtained to link the control aspect and communication aspect.Assuming that the base station has instantaneous channel state information(CSI)or statistical CSI,the thresholds of the sensing-control pattern activation are designed,respectively.Finally,an integrated scheduling scheme for performing communication,sensing,and control is proposed.Numerical results indicate that,compared with conventional time-triggered scheme,the proposed integrated scheduling scheme obtains comparable communication and control performance,but reduces the sensing consumed power by 52.46%.
基金a phased achievement of a major project of the National Social Science Fund of China,titled “Research on the Security Impact of the Situation in the Bay of Bengal Region on China’s East Data West Computing Project”(Project No.:22ZDA181)。
文摘Digital infrastructure possesses dual attributes as both an international public good and a strategic communication tool for major countries. In recent years, the US has been active in the field of global digital infrastructure, showing a trend of deep coupling and mutual embedding with strategic communication. The US has built a strategic communication system for digital infrastructure. This system is designed to set the international agenda, collect information and intelligence, and deter its competitors. The system presents a three-way coherent infrastructure of a basic layer, application layer,and value layer. The mode of operation is characterized by commercial force collaboration, alliance system linkage, and global multi-domain network layout. However, to maintain its unipolar digital hegemony,the United States has over-instrumentalized its digital infrastructure and exploited and amplified the asymmetry of digital science and technology for a long period of time, which not only highlights its unilateral stance and exclusionary nature but also results in a global digital divide and trust deficit, which will pose constraints on its sustainability in the long term.
基金supported in part by Chongqing Natural Science Foundation Innovation and Development Joint Fund(No.CSTB2024NSCQ-LMX0024)in part by Shanghai Natu-ral Science Foundation(No.24ZR1421800)。
文摘Low earth orbit(LEO)satellite communication which can provide global wireless ser-vice plays a critical role in the future wireless communication networks.However,due to the high speed of satellite motion,numerous narrow beams,and complex satellite-terrestrial channels,the initial access between the LEO satellites and user terminals(UEs)becomes more complicated.To establish a stable link,a beam search is required between the satellite and the UE.However,tradi-tional beam search methods(e.g.,exhaustive search)have high time complexity which is not suit-able in high-speed scenarios.Therefore,in this paper,a sensing-aided hierarchical beam search method is proposed,which is performed in two stages.In the first stage,wide beam scanning is per-formed to find the optimal angular range.In the second stage,after determining the directions of narrow beams via sensing the direction of arrival(DOA)of satellite signals,the narrow beams gen-erated at estimated directions are used to sweep the satellite beams.This method can help fast beam alignment and obtain high beam search accuracy,which is verified by simulation results.Moreover,we analyze the gain of beam alignment from the two-stage beam search method.
基金supported by the National Natural Science Foundation of China(Nos.U20B2038,62231027,62171462,61931011,62001514 and 62271501)。
文摘High-Frequency(HF)communication is widely used for long-distance transmission in remote and disaster areas.However,the dynamic nature of the ionosphere and multipath propagation in the HF channel pose significant challenges to designing efficient and robust communication systems.In this paper,we propose a Fixed Station(FS)and frequency matching method,as well as a power allocation method,to improve the sum-rate of air-to-ground HF communication networks.We derive optimal power allocation among users that share the same frequency,based on which a modified water-filling algorithm is used to solve the power allocation problem in multi-user scenarios,while a low-complexity algorithm is proposed to solve the integer optimization problem of frequency-FS matching.Simulation results demonstrate that the proposed algorithm outperforms the naive algorithm,indicating its effectiveness.
基金This study was co-supported by the National Natural Science Foundation of China(No.62025110&62271093)the Natural Science Foundation of Chongqing,China(No.CSTB2023NSCQ-LZX0108).
文摘In this work,we consider an Unmanned Aerial Vehicle(UAV)-aided covert transmission network,which adopts the uplink transmission of Communication Nodes(CNs)as a cover to facilitate covert transmission to a Primary Communication Node(PCN).Specifically,all nodes transmit to the UAV exploiting uplink non-Orthogonal Multiple Access(NOMA),while the UAV performs covert transmission to the PCN at the same frequency.To minimize the average age of covert information,we formulate a joint optimization problem of UAV trajectory and power allocation designing subject to multi-dimensional constraints including covertness demand,communication quality requirement,maximum flying speed,and the maximum available resources.To address this problem,we embed Signomial Programming(SP)into Deep Reinforcement Learning(DRL)and propose a DRL framework capable of handling the constrained Markov decision processes,named SP embedded Soft Actor-Critic(SSAC).By adopting SSAC,we achieve the joint optimization of UAV trajectory and power allocation.Our simulations show the optimized UAV trajectory and verify the superiority of SSAC compared with various existing baseline schemes.The results of this study suggest that by maintaining appropriate distances from both the PCN and CNs,one can effectively enhance the performance of covert communication by reducing the detection probability of the CNs.
基金supported in part by the National Natural Science Foundation of China under Grants 62201137 and 62331023in part by the Fundamental Research Funds for the Central Universities under Grant 2242022k60001in part by the Fundamental Research Funds for the Central Universities under Grant 2242025K20001。
文摘In this paper,we investigate an reconfigurable intelligent surface-aided Integrated Sensing And Communication(ISAC)system.Our objective is to maximize the achievable sum rate of the multi-antenna communication users through the joint active and passive beamforming.Specifically,the weighted minimum mean-square error method is first used to reformulate the original problem into an equivalent one.Then,we utilize an alternating optimization algorithm to decouple the optimization variables and decompose this challenging problem into two subproblems.Given reflecting coefficients,a penalty-based algorithm is utilized to deal with the non-convex radar Signal-to-Noise Ratio(SNR)constraints.For the given beamforming matrix of the base station,we apply majorization-minimization to transform the problem into a Quadratic Constraint Quadratic Programming(QCQP)problem,which is ultimately solved using a Semi-Definite Relaxation(SDR)based algorithm.Simulation results illustrate the advantage of deploying reconfigurable intelligent surface in the considered multi-user MultipleInput Multiple-Output(MIMO)ISAC systems.
基金supported in part by the National Natural Science Foundation of China(U2441226).
文摘In recent years,intensified environmental pollution and climate change have increasingly exposed the world to natural disasters such as earthquakes and floods,resulting in substantial economic losses[1].These disasters frequently damage terrestrial communication infrastructures,making the rapid deployment of emergency communication networks in affected areas critical in increasing rescue efficiency[2].
