This paper highlights the crucial role of Indonesia’s GNSS receiver network in advancing Equatorial Plasma Bubble(EPB)studies in Southeast and East Asia,as ionospheric irregularities within EPB can disrupt GNSS signa...This paper highlights the crucial role of Indonesia’s GNSS receiver network in advancing Equatorial Plasma Bubble(EPB)studies in Southeast and East Asia,as ionospheric irregularities within EPB can disrupt GNSS signals and degrade positioning accuracy.Managed by the Indonesian Geospatial Information Agency(BIG),the Indonesia Continuously Operating Reference Station(Ina-CORS)network comprises over 300 GNSS receivers spanning equatorial to southern low-latitude regions.Ina-CORS is uniquely situated to monitor EPB generation,zonal drift,and dissipation across Southeast Asia.We provide a practical tool for EPB research,by sharing two-dimensional rate of Total Electron Content(TEC)change index(ROTI)derived from this network.We generate ROTI maps with a 10-minute resolution,and samples from May 2024 are publicly available for further scientific research.Two preliminary findings from the ROTI maps of Ina-CORS are noteworthy.First,the Ina-CORS ROTI maps reveal that the irregularities within a broader EPB structure persist longer,increasing the potential for these irregularities to migrate farther eastward.Second,we demonstrate that combined ROTI maps from Ina-CORS and GNSS receivers in East Asia and Australia can be used to monitor the development of ionospheric irregularities in Southeast and East Asia.We have demonstrated the combined ROTI maps to capture the development of ionospheric irregularities in the Southeast/East Asian sector during the G5 Geomagnetic Storm on May 11,2024.We observed simultaneous ionospheric irregularities in Japan and Australia,respectively propagating northwestward and southwestward,before midnight,whereas Southeast Asia’s equatorial and low-latitude regions exhibited irregularities post-midnight.By sharing ROTI maps from Indonesia and integrating them with regional GNSS networks,researchers can conduct comprehensive EPB studies,enhancing the understanding of EPB behavior across Southeast and East Asia and contributing significantly to ionospheric research.展开更多
The Red Sea-Gulf of Suez-Cairo-Alexandria Clysmic-Trend in northern Egypt is the main earthquake zone in the country,with a moderate-to-high seismic hazard and a history of significant earthquakes caused by rifting an...The Red Sea-Gulf of Suez-Cairo-Alexandria Clysmic-Trend in northern Egypt is the main earthquake zone in the country,with a moderate-to-high seismic hazard and a history of significant earthquakes caused by rifting and active faulting.To improve our understanding of the tectonic and seismic processes in this area,more comprehensive imaging of the crustal structure is required.This can be achieved by increasing the number of receiver functions(RFs)recorded by the seismic stations in northern Egypt and the southeastern Mediterranean.Data handling and processing should also be automated to increase process efficiency.In this study,we developed a capsule neural network for automated selection of RFs.The model was trained on a dataset containing RFs(both selected and unselected)from five broadband stations in northern Egypt.Stations SLM,SIWA,KOT,NBNS,and NKL are located in the unstable shelf region of Egypt,where limited knowledge of the deep crustal structure is available.The proposed capsule neural network achieved an average precision of 80%on the test set.The automated selection of RFs using a capsule neural network has the potential to significantly improve the efficiency and accuracy of RF analysis,as demonstrated by the stacking test.This could lead to a better understanding of crustal structure and tectonic processes in northern Egypt and the southeastern Mediterranean.展开更多
In DSP-based SerDes application,it is essential for AFE to implement a pre-ADC equalization to provide a better sig-nal for ADC and DSP.To meet the various equalization requirements of different channel and transmitte...In DSP-based SerDes application,it is essential for AFE to implement a pre-ADC equalization to provide a better sig-nal for ADC and DSP.To meet the various equalization requirements of different channel and transmitter configurations,this paper presents a 112 Gbps DSP-Based PAM4 SerDes receiver with a wide band equalization tuning AFE.The AFE is realized by implementing source degeneration transconductance,feedforward high-pass branch and inductive feedback peaking TIA.The AFE offers a flexible equalization gain tuning of up to 17.5 dB at Nyquist frequency without affecting the DC gain.With the pro-posed AFE,the receiver demonstrates eye opening after digital FIR equalization and achieves 6×10^(-9) BER with a 29.6 dB inser-tion loss channel.展开更多
A Receiver Operating Characteristic(ROC)analysis of a power is important and useful in clinical trials.A Classical Conditional Power(CCP)is a probability of a classical rejection region given values of true treatment ...A Receiver Operating Characteristic(ROC)analysis of a power is important and useful in clinical trials.A Classical Conditional Power(CCP)is a probability of a classical rejection region given values of true treatment effect and interim result.For hypotheses and reversed hypotheses under normal models,we obtain analytical expressions of the ROC curves of the CCP,find optimal ROC curves of the CCP,investigate the superiority of the ROC curves of the CCP,calculate critical values of the False Positive Rate(FPR),True Positive Rate(TPR),and cutoff of the optimal CCP,and give go/no go decisions at the interim of the optimal CCP.In addition,extensive numerical experiments are carried out to exemplify our theoretical results.Finally,a real data example is performed to illustrate the go/no go decisions of the optimal CCP.展开更多
Orbital angular momentum(OAM)can achieve multifold increase of spectrum efficiency,but the hollow divergence characteristic and Line-of-Sight(LoS)path requirement impose the crucial challenges for vortex wave communic...Orbital angular momentum(OAM)can achieve multifold increase of spectrum efficiency,but the hollow divergence characteristic and Line-of-Sight(LoS)path requirement impose the crucial challenges for vortex wave communications.For air-to-ground vortex wave communications,where there exists the LoS path,this paper proposes a multi-user cooperative receive(MUCR)scheme to break through the communication distance limitation caused by the characteristic of vortex wave hollow divergence.In particular,we derive the optimal radial position corresponding to the maximum intensity,which is used to adjust the waist radius.Based on the waist radius and energy ring,the cooperative ground users having the minimum angular square difference are selected.Also,the signal compensation scheme is proposed to decompose OAM signals in air-to-ground vortex wave communications.Simulation results are presented to verify the superiority of our proposed MUCR scheme.展开更多
Existing Generalized Receive Spatial Modulation(GRSM)with Symbol-Level Precoding(SLP)forces the received signals(excluding noise)at unintended antennas to be zero,which restricts the generation of strong constructive ...Existing Generalized Receive Spatial Modulation(GRSM)with Symbol-Level Precoding(SLP)forces the received signals(excluding noise)at unintended antennas to be zero,which restricts the generation of strong constructive interference to intended receive antennas and thus limits the performance improvement over conventional GRSM with Zero-Forcing(ZF)precoding.In this paper,we propose a novel GRSM-SLP scheme that relaxes the zero receive power constraint and achieves superior performance by integrating Intelligent Reflecting Surfaces(IRSs).Specifically,our advanced GRSM-RSLP jointly exploits SLP at the transmitter and passive beamforming at the IRS to maximize the power difference between intended and unintended receive antennas,where the received signals at unintended antennas are relaxed to lie in a sphere centered at origin with a preset radius that depends on the Signal-to-Noise Ratio(SNR)value.The precoding matrix and passive beamforming vectors are optimized alternately by considering both phase shift keying and quadrature amplitude modulation signaling.It is worth emphasizing that GRSM-RSLP is a universal solution,also applicable to systems without IRS,although it performs better in IRS-assisted systems.We finally conduct extensive simulations to prove the superiority of GRSM-RSLP over GRSM-ZF and GRSM-SLP.Simulation results show that the performance of GRSM-RSLP is significantly influenced by the number of unintended antennas,and the larger the number,the better its performance.In the best-case scenario,GRSM-RSLP can achieve SNR gains of up to 10.5 dB and 12.5 dB over GRSM-SLP and GRSM-ZF,respectively.展开更多
In high-speed railway(HSR)wireless communication,the rapid channel changes and limited high-capacity access cause significant impact on the link performance.Meanwhile,the Doppler shift caused by high mobility leads to...In high-speed railway(HSR)wireless communication,the rapid channel changes and limited high-capacity access cause significant impact on the link performance.Meanwhile,the Doppler shift caused by high mobility leads to the inter-carrier interference.In this paper,we propose a reconfigurable intelligent surface(RIS)-assisted receive spatial modulation(SM)scheme based on the spatial-temporal correlated HSR Rician channel.The characteristics of SM and the phase shift adjustment of RIS are used to mitigate the performance degradation in high mobility scenarios.Considering the influence of channel spatial-temporal correlation and Doppler shift,the effects of different parameters on average bit error rate(BER)performance and upper bound of ergodic capacity are analyzed.Therefore,a joint antenna and RIS-unit selection algorithm based on the antenna removal method is proposed to increase the capacity performance of communication links.Numerical results show that the proposed RIS-assisted receive SM scheme can maintain high transmission capacity compared to the conventional HSR-SM scheme,whereas the degradation of BER performance can be compensated by arranging a large number of RIS-units.In addition,selecting more RIS-units has better capacity performance than activating more antennas in the low signal-to-noise ratio regions.展开更多
The geodetic detrending(GD)methodology was introduced in the past decade and has opened the door to the global monitoring of ionospheric scintillation using global navigation satellite system(GNSS)receivers.The perfor...The geodetic detrending(GD)methodology was introduced in the past decade and has opened the door to the global monitoring of ionospheric scintillation using global navigation satellite system(GNSS)receivers.The performance of GD has been demonstrated in geodetic receivers.However,extending scintillation monitoring to low-cost commercial receivers remains a challenge.Low-cost devices could serve as valuable complements to specialised and much more expensive scintillation monitoring receivers.In this paper,first,a feasibility study was conducted using the GD technique,demonstrating that the scintillation indices derived from the observations of two lowcost receivers(Septentrio Mosaic X5 and UBLOX ZED-F9P)have a resolution similar to that achieved by geodetic receiver models,whose price is one order of magnitude higher.Second,measurements of GNSS signals at different frequencies from the Galileo and global positioning system(GPS)satellites were analysed in a specific experiment over six days of null scintillation.Next,the noise level in the scintillation parameters derived from the experiment was evaluated,which shows that for low-cost receivers,the minimum scintillation detection threshold increases only negligibly compared to geodetic-grade receivers.Moreover,the geometry-free(GF)combination of L1 with a second signal of different frequency was investigated as an alternative to detrending GNSS signals.Finally,for determining the ionospheric fluctuations produced by scintillation,the limitations of using the GF combination versus the uncombined measurements were highlighted.It is concluded that the minimum resolution of scintillation indices derived from low-cost receiver measurements makes it possible to distinguish values associated with periods of scintillation activity from those produced by residual noise from mismodeling.For both geodetic and low-cost receivers,the scintillation detection threshold obtained with uncombined carrier-phase measurements is smaller than that achieved with the classic GF combination.展开更多
The Rydberg atom-based receiver, as a novel type of antenna, demonstrates broad application prospects in the field of microwave communications. However, since Rydberg atomic receivers are nonlinear systems, mismatches...The Rydberg atom-based receiver, as a novel type of antenna, demonstrates broad application prospects in the field of microwave communications. However, since Rydberg atomic receivers are nonlinear systems, mismatches between the parameters of the received amplitude modulation(AM) signals and the system's linear workspace and demodulation operating points can cause severe distortion in the demodulated signals. To address this, the article proposes a method for determining the operational parameters based on the mean square error(MSE) and total harmonic distortion(THD) assessments and presents strategies for optimizing the system's operational parameters focusing on linear response characteristics(LRC) and linear dynamic range(LDR). Specifically, we employ a method that minimizes the MSE to define the system's linear workspace, thereby ensuring the system has a good LRC while maximizing the LDR. To ensure that the signal always operates within the linear workspace, an appropriate carrier amplitude is set as the demodulation operating point. By calculating the THD at different operating points, the LRC performance within different regions of the linear workspace is evaluated, and corresponding optimization strategies based on the range of signal strengths are proposed. Moreover, to more accurately restore the baseband signal, we establish a mapping relationship between the carrier Rabi frequency and the transmitted power of the probe light, and optimize the slope of the linear demodulation function to reduce the MSE to less than 0.8×10^(-4). Finally, based on these methods for determining the operational parameters, we explore the effects of different laser Rabi frequencies on the system performance, and provide optimization recommendations. This research provides robust support for the design of high-performance Rydberg atom-based AM receivers.展开更多
In this paper,an interference cancellation based neural receiver for superimposed pilot(SIP)in multi-layer transmission is proposed,where the data and pilot are non-orthogonally superimposed in the same time-frequency...In this paper,an interference cancellation based neural receiver for superimposed pilot(SIP)in multi-layer transmission is proposed,where the data and pilot are non-orthogonally superimposed in the same time-frequency resource.Specifically,to deal with the intra-layer and inter-layer interference of SIP under multi-layer transmission,the interference cancellation with superimposed symbol aided channel estimation is leveraged in the neural receiver,accompanied by the pre-design of pilot code-division orthogonal mechanism at transmitter.In addition,to address the complexity issue for inter-vendor collaboration and the generalization problem in practical deployments,respectively,this paper also provides a fixed SIP(F-SIP)design based on constant pilot power ratio and scalable mechanisms for different modulation and coding schemes(MCSs)and transmission layers.Simulation results demonstrate the superiority of the proposed schemes on the performance of block error rate and throughput compared with existing counterparts.展开更多
In this paper,we investigate a distributed multi-input multi-output and orthogonal frequency division multiplexing(MIMO-OFDM) dual-functional radar-communication(DFRC) system,which enables simultaneous communication a...In this paper,we investigate a distributed multi-input multi-output and orthogonal frequency division multiplexing(MIMO-OFDM) dual-functional radar-communication(DFRC) system,which enables simultaneous communication and sensing in different subcarrier sets.To obtain the best tradeoff between communication and sensing performance,we first derive Cramer-Rao Bound(CRB) of targets in detection area,and then maximize the transmission rate by jointly optimizing the power/subcarriers allocation and the selection of radar receivers under the constraints of detection performance and total transmit power.To tackle the non-convex mixed integer programming problem,we decompose the original problem into a semidefinite programming(SDP) problem and a convex quadratic integer problem and solve them iteratively.The numerical results demonstrate the effectiveness of our proposed algorithm,as well as the performance improvement brought by optimizing radar receivers selection.展开更多
As a novel signaling technology,the power splitting receiver(PSR)simultaneously employs both the coherent and non-coherent signal processing.In order to improve its communication performance,an intelligent reflecting ...As a novel signaling technology,the power splitting receiver(PSR)simultaneously employs both the coherent and non-coherent signal processing.In order to improve its communication performance,an intelligent reflecting surface(IRS)is introduced into its signal propagation path.Consequently,an IRSaided PSR is concerned for a point-to-point(P2P)data link,where both the single-antenna and multiantenna deployments on the receiver are discussed.We aim at maximizing the capacity of the concerned P2P data-link by jointly optimizing the passive beamforming of IRS and the splitting ratio of PSR,either in single-antenna or multi-antenna case.However,owing to the coupling of multiple variables,the optimization problems are non-convex and challenging,especially in the later multi-antenna case.The proposed alternating-approximating algorithm(A-A),aided by semi-definite relaxation(SDR)and successive convex approximation(SCA)methods,etc.,successfully overcomes these challenges.We compare the IRS-aided PSR system that optimized by our proposed algorithm to the systems without IRS or PSR,and the systems without joint optimization.The simulation results show that our proposal has a better performance.展开更多
Based on the observational data from 60 short-period stations deployed in the Jishishan M6.2 earthquake epicenter and adjacent regions(Gansu Province,2023),this study inverted the near-surface S-wave velocity structur...Based on the observational data from 60 short-period stations deployed in the Jishishan M6.2 earthquake epicenter and adjacent regions(Gansu Province,2023),this study inverted the near-surface S-wave velocity structure through teleseismic receiver function analysis by using the amplitude of direct P-wave.The results reveal that the epicentral area(Liugou Township and surroundings)exhibits markedly low S-wave velocities of 400-600 m/s,with a mean value of(500±50)m/s.In contrast,intermountain basins-Guanting Basin and Dahejia Basin-demonstrate significantly elevated velocities,exceeding the epicentral zone by 100-300 m/s,with values concentrated at 600-900 m/s.Notably,localized areas such as Jintian Village and Caotan Village maintain stable S-wave velocities of(700±30)m/s.The western margin tectonic belt of Jishishan displays distinctive velocity differentiation:A pronounced velocity gradient zone along the 35.8°N latitude boundary separates northern areas(<550 m/s)from southern regions(>750 m/s).These findings demonstrate significant spatial heterogeneity in shallow S-wave velocity structures,primarily controlled by three factors:(1)topographic-geomorphic units,(2)stratigraphic lithological contrasts,and(3)anthropogenic modifications.The persistent low-velocity anomalies(<600 m/s)in the epicentral zone and northern Yellow River T2 terrace likely correlate with Quaternary unconsolidated sediments,enhanced groundwater circulation,and bedrock weathering.These results provide critical geophysical constraints for understanding both the seismogenic environment of the Jishishan earthquake and its damage distribution patterns.Furthermore,they establish a foundational framework for regional seismic intensity evaluation,site amplification analysis,and secondary hazard risk assessment.展开更多
Increasing the number of atoms that interact with microwave fields represents a promising strategy for enhancing the sensitivity of Rydberg atom-based superheterodyne receivers.Nevertheless,the practical implementatio...Increasing the number of atoms that interact with microwave fields represents a promising strategy for enhancing the sensitivity of Rydberg atom-based superheterodyne receivers.Nevertheless,the practical implementation of this approach is impeded by adverse effects such as excitation saturation of Rydberg atoms and power broadening.Here,we demonstrate enhanced microwave field measurements based on two specific velocity groups of atoms,simultaneously addressed by dual-channel probe beams in a Sagnac loop interferometer.The application of resonance detuning in two-photon excitation enables selective addressing of atoms moving along the beam direction,thereby significantly mitigating atomic transit noise.At 7.97 GHz,our method yields a 3 dB improvement in signal-to-noise ratio(SNR),achieving a sensitivity of 10.7 nV·cm^(−1)·Hz^(−1/2).This approach offers a viable pathway to further improve the sensitivity of Rydberg atom-based microwave electrometers.展开更多
In planning and executing marine controlled-source electromagnetic methods, seafloor electromagnetic receivers must overcome the problems of noise, clock drift, and power consumption. To design a receiver that perform...In planning and executing marine controlled-source electromagnetic methods, seafloor electromagnetic receivers must overcome the problems of noise, clock drift, and power consumption. To design a receiver that performs well and overcomes the abovementioned problems, we performed forward modeling of the E-field abnormal response and established the receiver＇s characteristics. We describe the design optimization and the properties of each component, that is, low-noise induction coil sensor, low-noise Ag/AgCI electrode, low-noise chopper amplifier, digital temperature-compensated crystal oscillator module, acoustic telemetry modem, and burn wire system. Finally, we discuss the results of onshore and offshore field tests to show the effectiveness of the developed seafloor electromagnetic receiver and its performance： typical E-field noise of 0.12 nV/m/rt（Hz） at 0.5 Hz, dynamic range higher than 120 dB, clock drift lower than 1 ms/day, and continuous operation of at least 21 days.展开更多
A new integrity metric for navigation systems is proposed based on the measurement domain. Proba-hilistic optimization design offers tools for fault detection by considering the required navigation performance （RNP）...A new integrity metric for navigation systems is proposed based on the measurement domain. Proba-hilistic optimization design offers tools for fault detection by considering the required navigation performance （RNP） parameter and the uncertainty noise. The choice of the proper performance parameter provided the single-valued mapping with the missed detection probability estimates the probability of failure. The desirable characteristics of the residual sensitivity matrix are exploited to increase the efficiency for identifying erroneous observations. The algorithm can be used to support the performance specification and the efficient calculation of the integrity monitoring process. The simulation for non-precision approach （NPA） validates both the viability and the effectiveness of the proposed algorithm.展开更多
The design of a global positioning system （GPS） software receiver is introduced. This design uses the concept of software radio, and it consists of the following parts： front-end, acquisition, tracking, synchroniza...The design of a global positioning system （GPS） software receiver is introduced. This design uses the concept of software radio, and it consists of the following parts： front-end, acquisition, tracking, synchronization, navigation solution and some assisting modules. In the acquisition module, the acquisition algorithm based on circular correlation is utilized. The input data and the local code are converted into the frequency domain by means of the fast Fourier transform （FFT）. After performing circular correlation, the initial phase of the C/A code can be obtained and the cartier frequency can be found in 1 kHz frequency resolution, which is too coarse to use for the tracking loop. In order to improve the frequency resolution, the fine frequency estimation through a phase relationship is then achieved, by which, the frequency resolution is improved dramatically. Experiments show that the inaccuracy of the carrier frequency can be estimated within a few hertz by the fine frequency estimation method, and the fine frequency attained can be directly used for the tracking loop.展开更多
A wideband monolithic optoelectronic integrated receiver with a high-speed photo-detector,completely compatible with standard CMOS processes,is designed and implemented in 0.6μm standard CMOS technology.The experimen...A wideband monolithic optoelectronic integrated receiver with a high-speed photo-detector,completely compatible with standard CMOS processes,is designed and implemented in 0.6μm standard CMOS technology.The experimental results demonstrate that its performance approaches applicable requirements,where the photo-detector achieves a -3dB frequency of 1.11GHz,and the receiver achieves a 3dB bandwidth of 733MHz and a sensitivity of -9dBm for λ=850nm at BER=10-12.展开更多
A direct conversion receiver with optimized tolerance to local carrier interference is designed and implemented in a 0.18μm 1P6M mixed-signal CMOS process for a 900MHz RFID reader transceiver. A baseband amplifier wi...A direct conversion receiver with optimized tolerance to local carrier interference is designed and implemented in a 0.18μm 1P6M mixed-signal CMOS process for a 900MHz RFID reader transceiver. A baseband amplifier with series feedback topology is proposed to achieve passive mixer buffering,baseband DC cancellation,and signal amplification simultaneously. The receiver has a measured input ldB compression point of - 4dBm and a sensitivity of - 70dBm when 10dB SNR for digital demodulation is required. The receiver is integrated in a reader transceiver chip and consumes 90mA from a 1.8V supply.展开更多
A novel high-bandwidth, high-sensitivity differential optical receiver without any additional cost compared to general optical receivers, is proposed for high-speed optical communications and interconnections. High ba...A novel high-bandwidth, high-sensitivity differential optical receiver without any additional cost compared to general optical receivers, is proposed for high-speed optical communications and interconnections. High bandwidth and high sensitivity are achieved through a fully differential transimpedance amplifier with balanced input loads and two photodetectors to convert the incident light into a pair of differential photogenerated currents,respectively. In addition,a corresponding 0.35μm standard CMOS optoelectronic integrated receiver with two 60μm × 30μm, 1. 483pF fingered p^＋/n- well/p-substrate photodiodes is also presented. The simulation results demonstrate that it achieves a 1.37GHz bandwidth and a 81.9dBΩ transimpedance gain,supporting data rates up to at least 2Gbit/s. The device consumes a core area of 0. 198mm^2 and the optical sensitivity is at least - 13dBm for a 10^-12 bit error rate under a 2^15 - 1 PRBS input signal.展开更多
基金JSPS KAKENHI Grant Number16H06286 supports global GNSS ionospheric maps (TEC,ROTI,and detrended TEC maps) developed by the Institute for SpaceEarth Environmental Research (ISEE) of Nagoya Universitysupport of the 2024 JASSO Follow-up Research Fellowship Program for a 90-day visiting research at the Institute for Space-Earth Environmental Research (ISEE),Nagoya University+3 种基金the support received from Telkom University under the“Skema Penelitian Terapan Periode I Tahun Anggaran 2024”the Memorandum of Understanding for Research Collaboration on Regional Ionospheric Observation (No:092/SAM3/TE-DEK/2021)the National Institute of Information and Communications Technology (NICT) International Exchange Program 2024-2025(No.2024-007)support for a one-year visiting research at Hokkaido University
文摘This paper highlights the crucial role of Indonesia’s GNSS receiver network in advancing Equatorial Plasma Bubble(EPB)studies in Southeast and East Asia,as ionospheric irregularities within EPB can disrupt GNSS signals and degrade positioning accuracy.Managed by the Indonesian Geospatial Information Agency(BIG),the Indonesia Continuously Operating Reference Station(Ina-CORS)network comprises over 300 GNSS receivers spanning equatorial to southern low-latitude regions.Ina-CORS is uniquely situated to monitor EPB generation,zonal drift,and dissipation across Southeast Asia.We provide a practical tool for EPB research,by sharing two-dimensional rate of Total Electron Content(TEC)change index(ROTI)derived from this network.We generate ROTI maps with a 10-minute resolution,and samples from May 2024 are publicly available for further scientific research.Two preliminary findings from the ROTI maps of Ina-CORS are noteworthy.First,the Ina-CORS ROTI maps reveal that the irregularities within a broader EPB structure persist longer,increasing the potential for these irregularities to migrate farther eastward.Second,we demonstrate that combined ROTI maps from Ina-CORS and GNSS receivers in East Asia and Australia can be used to monitor the development of ionospheric irregularities in Southeast and East Asia.We have demonstrated the combined ROTI maps to capture the development of ionospheric irregularities in the Southeast/East Asian sector during the G5 Geomagnetic Storm on May 11,2024.We observed simultaneous ionospheric irregularities in Japan and Australia,respectively propagating northwestward and southwestward,before midnight,whereas Southeast Asia’s equatorial and low-latitude regions exhibited irregularities post-midnight.By sharing ROTI maps from Indonesia and integrating them with regional GNSS networks,researchers can conduct comprehensive EPB studies,enhancing the understanding of EPB behavior across Southeast and East Asia and contributing significantly to ionospheric research.
文摘The Red Sea-Gulf of Suez-Cairo-Alexandria Clysmic-Trend in northern Egypt is the main earthquake zone in the country,with a moderate-to-high seismic hazard and a history of significant earthquakes caused by rifting and active faulting.To improve our understanding of the tectonic and seismic processes in this area,more comprehensive imaging of the crustal structure is required.This can be achieved by increasing the number of receiver functions(RFs)recorded by the seismic stations in northern Egypt and the southeastern Mediterranean.Data handling and processing should also be automated to increase process efficiency.In this study,we developed a capsule neural network for automated selection of RFs.The model was trained on a dataset containing RFs(both selected and unselected)from five broadband stations in northern Egypt.Stations SLM,SIWA,KOT,NBNS,and NKL are located in the unstable shelf region of Egypt,where limited knowledge of the deep crustal structure is available.The proposed capsule neural network achieved an average precision of 80%on the test set.The automated selection of RFs using a capsule neural network has the potential to significantly improve the efficiency and accuracy of RF analysis,as demonstrated by the stacking test.This could lead to a better understanding of crustal structure and tectonic processes in northern Egypt and the southeastern Mediterranean.
基金supported by National Key R&D Program of China No.2022YFB2803401.
文摘In DSP-based SerDes application,it is essential for AFE to implement a pre-ADC equalization to provide a better sig-nal for ADC and DSP.To meet the various equalization requirements of different channel and transmitter configurations,this paper presents a 112 Gbps DSP-Based PAM4 SerDes receiver with a wide band equalization tuning AFE.The AFE is realized by implementing source degeneration transconductance,feedforward high-pass branch and inductive feedback peaking TIA.The AFE offers a flexible equalization gain tuning of up to 17.5 dB at Nyquist frequency without affecting the DC gain.With the pro-posed AFE,the receiver demonstrates eye opening after digital FIR equalization and achieves 6×10^(-9) BER with a 29.6 dB inser-tion loss channel.
基金supported by the National Social Science Fund of China(Grand No.21XTJ001).
文摘A Receiver Operating Characteristic(ROC)analysis of a power is important and useful in clinical trials.A Classical Conditional Power(CCP)is a probability of a classical rejection region given values of true treatment effect and interim result.For hypotheses and reversed hypotheses under normal models,we obtain analytical expressions of the ROC curves of the CCP,find optimal ROC curves of the CCP,investigate the superiority of the ROC curves of the CCP,calculate critical values of the False Positive Rate(FPR),True Positive Rate(TPR),and cutoff of the optimal CCP,and give go/no go decisions at the interim of the optimal CCP.In addition,extensive numerical experiments are carried out to exemplify our theoretical results.Finally,a real data example is performed to illustrate the go/no go decisions of the optimal CCP.
基金supported in part by National Natural Science Foundation of China under Grant 62441115 and 62201427in part by the Ministry of Industry and Information Technology of the People’s Republic of China under Grant CBG01N23-01-04.
文摘Orbital angular momentum(OAM)can achieve multifold increase of spectrum efficiency,but the hollow divergence characteristic and Line-of-Sight(LoS)path requirement impose the crucial challenges for vortex wave communications.For air-to-ground vortex wave communications,where there exists the LoS path,this paper proposes a multi-user cooperative receive(MUCR)scheme to break through the communication distance limitation caused by the characteristic of vortex wave hollow divergence.In particular,we derive the optimal radial position corresponding to the maximum intensity,which is used to adjust the waist radius.Based on the waist radius and energy ring,the cooperative ground users having the minimum angular square difference are selected.Also,the signal compensation scheme is proposed to decompose OAM signals in air-to-ground vortex wave communications.Simulation results are presented to verify the superiority of our proposed MUCR scheme.
基金supported in part by the National Key R&D Program of China under Grant 2023YFB2904500in part by the National Natural Science Foundation of China under Grant 62471183in part by the Fundamental Research Funds for the Central Universities under Grant 2024ZYGXZR076.
文摘Existing Generalized Receive Spatial Modulation(GRSM)with Symbol-Level Precoding(SLP)forces the received signals(excluding noise)at unintended antennas to be zero,which restricts the generation of strong constructive interference to intended receive antennas and thus limits the performance improvement over conventional GRSM with Zero-Forcing(ZF)precoding.In this paper,we propose a novel GRSM-SLP scheme that relaxes the zero receive power constraint and achieves superior performance by integrating Intelligent Reflecting Surfaces(IRSs).Specifically,our advanced GRSM-RSLP jointly exploits SLP at the transmitter and passive beamforming at the IRS to maximize the power difference between intended and unintended receive antennas,where the received signals at unintended antennas are relaxed to lie in a sphere centered at origin with a preset radius that depends on the Signal-to-Noise Ratio(SNR)value.The precoding matrix and passive beamforming vectors are optimized alternately by considering both phase shift keying and quadrature amplitude modulation signaling.It is worth emphasizing that GRSM-RSLP is a universal solution,also applicable to systems without IRS,although it performs better in IRS-assisted systems.We finally conduct extensive simulations to prove the superiority of GRSM-RSLP over GRSM-ZF and GRSM-SLP.Simulation results show that the performance of GRSM-RSLP is significantly influenced by the number of unintended antennas,and the larger the number,the better its performance.In the best-case scenario,GRSM-RSLP can achieve SNR gains of up to 10.5 dB and 12.5 dB over GRSM-SLP and GRSM-ZF,respectively.
基金supported in part by National Natural Science Foundation of China under Grant 62461024Jiangxi Provincial Natural Science Foundation of China under Grant 20224ACB202001.
文摘In high-speed railway(HSR)wireless communication,the rapid channel changes and limited high-capacity access cause significant impact on the link performance.Meanwhile,the Doppler shift caused by high mobility leads to the inter-carrier interference.In this paper,we propose a reconfigurable intelligent surface(RIS)-assisted receive spatial modulation(SM)scheme based on the spatial-temporal correlated HSR Rician channel.The characteristics of SM and the phase shift adjustment of RIS are used to mitigate the performance degradation in high mobility scenarios.Considering the influence of channel spatial-temporal correlation and Doppler shift,the effects of different parameters on average bit error rate(BER)performance and upper bound of ergodic capacity are analyzed.Therefore,a joint antenna and RIS-unit selection algorithm based on the antenna removal method is proposed to increase the capacity performance of communication links.Numerical results show that the proposed RIS-assisted receive SM scheme can maintain high transmission capacity compared to the conventional HSR-SM scheme,whereas the degradation of BER performance can be compensated by arranging a large number of RIS-units.In addition,selecting more RIS-units has better capacity performance than activating more antennas in the low signal-to-noise ratio regions.
基金funding from European Union(MCIN/AEI/10.13039/501100011033/FEDER)(Nos.PID2022-138485OB-I00 and CNS2022-135383)European Space Agency(RT-WMIS)(No.4000137762/22/NL/GLC/ov)funding support from the China Scholarship Council(No.202006020025)。
文摘The geodetic detrending(GD)methodology was introduced in the past decade and has opened the door to the global monitoring of ionospheric scintillation using global navigation satellite system(GNSS)receivers.The performance of GD has been demonstrated in geodetic receivers.However,extending scintillation monitoring to low-cost commercial receivers remains a challenge.Low-cost devices could serve as valuable complements to specialised and much more expensive scintillation monitoring receivers.In this paper,first,a feasibility study was conducted using the GD technique,demonstrating that the scintillation indices derived from the observations of two lowcost receivers(Septentrio Mosaic X5 and UBLOX ZED-F9P)have a resolution similar to that achieved by geodetic receiver models,whose price is one order of magnitude higher.Second,measurements of GNSS signals at different frequencies from the Galileo and global positioning system(GPS)satellites were analysed in a specific experiment over six days of null scintillation.Next,the noise level in the scintillation parameters derived from the experiment was evaluated,which shows that for low-cost receivers,the minimum scintillation detection threshold increases only negligibly compared to geodetic-grade receivers.Moreover,the geometry-free(GF)combination of L1 with a second signal of different frequency was investigated as an alternative to detrending GNSS signals.Finally,for determining the ionospheric fluctuations produced by scintillation,the limitations of using the GF combination versus the uncombined measurements were highlighted.It is concluded that the minimum resolution of scintillation indices derived from low-cost receiver measurements makes it possible to distinguish values associated with periods of scintillation activity from those produced by residual noise from mismodeling.For both geodetic and low-cost receivers,the scintillation detection threshold obtained with uncombined carrier-phase measurements is smaller than that achieved with the classic GF combination.
基金Project supported by the National Natural Science Foundation of China (Grant No. U22B2095)the Civil Aerospace Technology Research Project (Grant No. D010103)。
文摘The Rydberg atom-based receiver, as a novel type of antenna, demonstrates broad application prospects in the field of microwave communications. However, since Rydberg atomic receivers are nonlinear systems, mismatches between the parameters of the received amplitude modulation(AM) signals and the system's linear workspace and demodulation operating points can cause severe distortion in the demodulated signals. To address this, the article proposes a method for determining the operational parameters based on the mean square error(MSE) and total harmonic distortion(THD) assessments and presents strategies for optimizing the system's operational parameters focusing on linear response characteristics(LRC) and linear dynamic range(LDR). Specifically, we employ a method that minimizes the MSE to define the system's linear workspace, thereby ensuring the system has a good LRC while maximizing the LDR. To ensure that the signal always operates within the linear workspace, an appropriate carrier amplitude is set as the demodulation operating point. By calculating the THD at different operating points, the LRC performance within different regions of the linear workspace is evaluated, and corresponding optimization strategies based on the range of signal strengths are proposed. Moreover, to more accurately restore the baseband signal, we establish a mapping relationship between the carrier Rabi frequency and the transmitted power of the probe light, and optimize the slope of the linear demodulation function to reduce the MSE to less than 0.8×10^(-4). Finally, based on these methods for determining the operational parameters, we explore the effects of different laser Rabi frequencies on the system performance, and provide optimization recommendations. This research provides robust support for the design of high-performance Rydberg atom-based AM receivers.
文摘In this paper,an interference cancellation based neural receiver for superimposed pilot(SIP)in multi-layer transmission is proposed,where the data and pilot are non-orthogonally superimposed in the same time-frequency resource.Specifically,to deal with the intra-layer and inter-layer interference of SIP under multi-layer transmission,the interference cancellation with superimposed symbol aided channel estimation is leveraged in the neural receiver,accompanied by the pre-design of pilot code-division orthogonal mechanism at transmitter.In addition,to address the complexity issue for inter-vendor collaboration and the generalization problem in practical deployments,respectively,this paper also provides a fixed SIP(F-SIP)design based on constant pilot power ratio and scalable mechanisms for different modulation and coding schemes(MCSs)and transmission layers.Simulation results demonstrate the superiority of the proposed schemes on the performance of block error rate and throughput compared with existing counterparts.
基金supported by the National Key R&D Program of China (2023YFB2905605)the National Natural Science Foundation of China (62072229)。
文摘In this paper,we investigate a distributed multi-input multi-output and orthogonal frequency division multiplexing(MIMO-OFDM) dual-functional radar-communication(DFRC) system,which enables simultaneous communication and sensing in different subcarrier sets.To obtain the best tradeoff between communication and sensing performance,we first derive Cramer-Rao Bound(CRB) of targets in detection area,and then maximize the transmission rate by jointly optimizing the power/subcarriers allocation and the selection of radar receivers under the constraints of detection performance and total transmit power.To tackle the non-convex mixed integer programming problem,we decompose the original problem into a semidefinite programming(SDP) problem and a convex quadratic integer problem and solve them iteratively.The numerical results demonstrate the effectiveness of our proposed algorithm,as well as the performance improvement brought by optimizing radar receivers selection.
基金supported by National Key R&D Program of China with Grant number 2019YFB1803400in part by Sichuan Science and Technology Program under Grant 2024NSFSC0472。
文摘As a novel signaling technology,the power splitting receiver(PSR)simultaneously employs both the coherent and non-coherent signal processing.In order to improve its communication performance,an intelligent reflecting surface(IRS)is introduced into its signal propagation path.Consequently,an IRSaided PSR is concerned for a point-to-point(P2P)data link,where both the single-antenna and multiantenna deployments on the receiver are discussed.We aim at maximizing the capacity of the concerned P2P data-link by jointly optimizing the passive beamforming of IRS and the splitting ratio of PSR,either in single-antenna or multi-antenna case.However,owing to the coupling of multiple variables,the optimization problems are non-convex and challenging,especially in the later multi-antenna case.The proposed alternating-approximating algorithm(A-A),aided by semi-definite relaxation(SDR)and successive convex approximation(SCA)methods,etc.,successfully overcomes these challenges.We compare the IRS-aided PSR system that optimized by our proposed algorithm to the systems without IRS or PSR,and the systems without joint optimization.The simulation results show that our proposal has a better performance.
基金project is supported in part by Broadband Seismic 3D Array Detection(PhaseⅠ),Deep Earth Probe and Mineral Resources Exploration-National Science and Technology Major Project(Grant No.2024ZD1000300)National Natural Science Foundation of China(42204061)Gansu Jishishan 6.2 magnitude earthquake scientific investigation(DQJB23Y45)program。
文摘Based on the observational data from 60 short-period stations deployed in the Jishishan M6.2 earthquake epicenter and adjacent regions(Gansu Province,2023),this study inverted the near-surface S-wave velocity structure through teleseismic receiver function analysis by using the amplitude of direct P-wave.The results reveal that the epicentral area(Liugou Township and surroundings)exhibits markedly low S-wave velocities of 400-600 m/s,with a mean value of(500±50)m/s.In contrast,intermountain basins-Guanting Basin and Dahejia Basin-demonstrate significantly elevated velocities,exceeding the epicentral zone by 100-300 m/s,with values concentrated at 600-900 m/s.Notably,localized areas such as Jintian Village and Caotan Village maintain stable S-wave velocities of(700±30)m/s.The western margin tectonic belt of Jishishan displays distinctive velocity differentiation:A pronounced velocity gradient zone along the 35.8°N latitude boundary separates northern areas(<550 m/s)from southern regions(>750 m/s).These findings demonstrate significant spatial heterogeneity in shallow S-wave velocity structures,primarily controlled by three factors:(1)topographic-geomorphic units,(2)stratigraphic lithological contrasts,and(3)anthropogenic modifications.The persistent low-velocity anomalies(<600 m/s)in the epicentral zone and northern Yellow River T2 terrace likely correlate with Quaternary unconsolidated sediments,enhanced groundwater circulation,and bedrock weathering.These results provide critical geophysical constraints for understanding both the seismogenic environment of the Jishishan earthquake and its damage distribution patterns.Furthermore,they establish a foundational framework for regional seismic intensity evaluation,site amplification analysis,and secondary hazard risk assessment.
基金supported by the National Key R&D Program of China(Grant No.2022YFA1404003)the National Natural Science Foundation of China(Grant Nos.T2495252,12104279,and 123B2062)+2 种基金the Innovation Program for Quantum Science and Technology(Grant No.2021ZD0302100)the Fund for Shanxi“1331 Project”Key Subjects Constructionthe Bairen Project of Shanxi Province。
文摘Increasing the number of atoms that interact with microwave fields represents a promising strategy for enhancing the sensitivity of Rydberg atom-based superheterodyne receivers.Nevertheless,the practical implementation of this approach is impeded by adverse effects such as excitation saturation of Rydberg atoms and power broadening.Here,we demonstrate enhanced microwave field measurements based on two specific velocity groups of atoms,simultaneously addressed by dual-channel probe beams in a Sagnac loop interferometer.The application of resonance detuning in two-photon excitation enables selective addressing of atoms moving along the beam direction,thereby significantly mitigating atomic transit noise.At 7.97 GHz,our method yields a 3 dB improvement in signal-to-noise ratio(SNR),achieving a sensitivity of 10.7 nV·cm^(−1)·Hz^(−1/2).This approach offers a viable pathway to further improve the sensitivity of Rydberg atom-based microwave electrometers.
基金sponsored by the 863 Program(No.2009AA09A2012012AA09A201)+1 种基金China Geological Survey Project(No.201100307)the Fundamental Research Funds of the Ministry of Education for the Central Universities(No.2652011249)
文摘In planning and executing marine controlled-source electromagnetic methods, seafloor electromagnetic receivers must overcome the problems of noise, clock drift, and power consumption. To design a receiver that performs well and overcomes the abovementioned problems, we performed forward modeling of the E-field abnormal response and established the receiver＇s characteristics. We describe the design optimization and the properties of each component, that is, low-noise induction coil sensor, low-noise Ag/AgCI electrode, low-noise chopper amplifier, digital temperature-compensated crystal oscillator module, acoustic telemetry modem, and burn wire system. Finally, we discuss the results of onshore and offshore field tests to show the effectiveness of the developed seafloor electromagnetic receiver and its performance： typical E-field noise of 0.12 nV/m/rt（Hz） at 0.5 Hz, dynamic range higher than 120 dB, clock drift lower than 1 ms/day, and continuous operation of at least 21 days.
基金Supported by the National High Technology Research and Development Program of China (‘863’Program) (2006AA12Z313)~~
文摘A new integrity metric for navigation systems is proposed based on the measurement domain. Proba-hilistic optimization design offers tools for fault detection by considering the required navigation performance （RNP） parameter and the uncertainty noise. The choice of the proper performance parameter provided the single-valued mapping with the missed detection probability estimates the probability of failure. The desirable characteristics of the residual sensitivity matrix are exploited to increase the efficiency for identifying erroneous observations. The algorithm can be used to support the performance specification and the efficient calculation of the integrity monitoring process. The simulation for non-precision approach （NPA） validates both the viability and the effectiveness of the proposed algorithm.
基金Program for New Century Excellent Talents in Universi-ty(No.NCET-06-0462)Excellent Young Teacher Foundation of SoutheastUniversity(No.4022001002).
文摘The design of a global positioning system （GPS） software receiver is introduced. This design uses the concept of software radio, and it consists of the following parts： front-end, acquisition, tracking, synchronization, navigation solution and some assisting modules. In the acquisition module, the acquisition algorithm based on circular correlation is utilized. The input data and the local code are converted into the frequency domain by means of the fast Fourier transform （FFT）. After performing circular correlation, the initial phase of the C/A code can be obtained and the cartier frequency can be found in 1 kHz frequency resolution, which is too coarse to use for the tracking loop. In order to improve the frequency resolution, the fine frequency estimation through a phase relationship is then achieved, by which, the frequency resolution is improved dramatically. Experiments show that the inaccuracy of the carrier frequency can be estimated within a few hertz by the fine frequency estimation method, and the fine frequency attained can be directly used for the tracking loop.
文摘A wideband monolithic optoelectronic integrated receiver with a high-speed photo-detector,completely compatible with standard CMOS processes,is designed and implemented in 0.6μm standard CMOS technology.The experimental results demonstrate that its performance approaches applicable requirements,where the photo-detector achieves a -3dB frequency of 1.11GHz,and the receiver achieves a 3dB bandwidth of 733MHz and a sensitivity of -9dBm for λ=850nm at BER=10-12.
基金the Science and Technology Commission of Shanghai Municipality(No.057062010)the EU BRIDGE Project(No.033546)~~
文摘A direct conversion receiver with optimized tolerance to local carrier interference is designed and implemented in a 0.18μm 1P6M mixed-signal CMOS process for a 900MHz RFID reader transceiver. A baseband amplifier with series feedback topology is proposed to achieve passive mixer buffering,baseband DC cancellation,and signal amplification simultaneously. The receiver has a measured input ldB compression point of - 4dBm and a sensitivity of - 70dBm when 10dB SNR for digital demodulation is required. The receiver is integrated in a reader transceiver chip and consumes 90mA from a 1.8V supply.
文摘A novel high-bandwidth, high-sensitivity differential optical receiver without any additional cost compared to general optical receivers, is proposed for high-speed optical communications and interconnections. High bandwidth and high sensitivity are achieved through a fully differential transimpedance amplifier with balanced input loads and two photodetectors to convert the incident light into a pair of differential photogenerated currents,respectively. In addition,a corresponding 0.35μm standard CMOS optoelectronic integrated receiver with two 60μm × 30μm, 1. 483pF fingered p^＋/n- well/p-substrate photodiodes is also presented. The simulation results demonstrate that it achieves a 1.37GHz bandwidth and a 81.9dBΩ transimpedance gain,supporting data rates up to at least 2Gbit/s. The device consumes a core area of 0. 198mm^2 and the optical sensitivity is at least - 13dBm for a 10^-12 bit error rate under a 2^15 - 1 PRBS input signal.
