The body channel based wireless power transfer(BC-WPT)method utilizes the human body as the medium to transfer power for bioelectronics,which can achieve a lower transmission loss due to its higher conductivity.Howeve...The body channel based wireless power transfer(BC-WPT)method utilizes the human body as the medium to transfer power for bioelectronics,which can achieve a lower transmission loss due to its higher conductivity.However,except for the channel length,different on-body loca-tions of the transmitter and receiver also influence the power supply performance.This paper fo-cuses on the wrist-to-forehead path to show the potential of BC-WPT for the brain bioelectronics such as the brain computer interface device.The channel characteristics from 10 MHz to 60 MHz are measured by a vector network analyzer(VNA)and a prototype BC-WPT system with differ-ent copper electrodes and the lowest power loss locates between-22 dB and-33 dB.Furthermore,the minimum path loss limit is simulated in Advanced Design System(ADS)software and the low-est optimum path loss can reach nearly-13 dB.Finally,a rectifier circuit is also built at the receiv-er side to harvest d.c.voltage.The results show that the open-circuit voltage(OCV)can reach 1.75 V with the transmitter of 50Ωoutput impedance supplying 5V_(pp)sine voltage at 60 MHz when adopt-ing 1 cm-diameter circular electrodes.展开更多
It is extensively approved that Channel State Information(CSI) plays an important role for synergetic transmission and interference management. However, pilot overhead to obtain CSI with enough precision is a signific...It is extensively approved that Channel State Information(CSI) plays an important role for synergetic transmission and interference management. However, pilot overhead to obtain CSI with enough precision is a significant issue for wireless communication networks with massive antennas and ultra-dense cell. This paper proposes a learning- based channel model, which can estimate, refine, and manage CSI for a synergetic transmission system. It decomposes the channel impulse response into multiple paths, and uses a learning-based algorithm to estimate paths' parameters without notable degradation caused by sparse pilots. Both indoor measurement and outdoor measurement are conducted to verify the feasibility of the proposed channel model preliminarily.展开更多
A more general narrowband regular-shaped geometry-based statistical model(RS-GBSM) combined with the line of sight(LoS) and single bounce(SB) rays for unmanned aerial vehicle(UAV) multiple-input multiple-output(MIMO) ...A more general narrowband regular-shaped geometry-based statistical model(RS-GBSM) combined with the line of sight(LoS) and single bounce(SB) rays for unmanned aerial vehicle(UAV) multiple-input multiple-output(MIMO) channel is proposed in this paper. The channel characteristics, including space-time correlation function(STCF), Doppler power spectral density(DPSD), level crossing rate(LCR) and average fade duration(AFD), are derived based on the single sphere reference model for a non-isotropic environment. The corresponding sum-of-sinusoids(SoS) simulation models including both the deterministic model and statistical model with finite scatterers are also proposed for practicable implementation. The simulation results illustrate that the simulation models well reproduce the channel characteristics of the single sphere reference model with sufficient simulation scatterers. And the statistical model has a better approximation of the reference model in comparison with the deterministic one when the simulation trials of the stochastic model are sufficient. The effects of the parameters such as flight height, moving direction and Rice factor on the characteristics are also studied.展开更多
A multistandard software-defined radio base station must perform non-uniform channelization of multiplexed frequency bands. Non-uniform channelization accounts for a significant portion of the digital signal processin...A multistandard software-defined radio base station must perform non-uniform channelization of multiplexed frequency bands. Non-uniform channelization accounts for a significant portion of the digital signal processing workload in the base station receiver and can be difficult to realize in a physical implementation. In non-uniform channelization methods based on generalized DFT filter banks, large prototype filter orders are a significant issue for implementation. In this paper, a multistage filter design is applied to two different non-uniform generalized DFT-based channelizers in order to reduce their filter orders. To evaluate the approach, a TETRA and TEDS base station is used. Experimental results show that the new multistage design reduces both the number of coefficients and operations and leads to a more feasible design and practical physical implementation.展开更多
Spectrum sensing is one of the key technologies in Cognitive Radios(CRs).Previous works are accomplished under simple channel models,which may lead to unreliable results when it applied to the over-the-air systems.In ...Spectrum sensing is one of the key technologies in Cognitive Radios(CRs).Previous works are accomplished under simple channel models,which may lead to unreliable results when it applied to the over-the-air systems.In this paper,we investigate the performance of a Multi-Resolution Spectrum Sensing(MRSS) algorithm under measurement-based channel models in China.MRSS is a wavelet based algorithm which is suitable for non-stationary,wideband signal analysis.Using statistical mod-eling,measurement-based channel models are presented under typical urban and suburban scenarios in Shanghai,China.Then,the performance of the MRSS algorithm is evaluated under the measure-ment-based channel models.Simulation results show that,using MRSS,the performance is always better in the scenarios where Line-Of-Sight(LOS) path exist;also,in LOS scenarios,rich scattering effect helps to increase the performance.展开更多
Comprehensive radiation characteristics of polarized antenna are crucial in creating practical channel coefficients for next generation wireless communication system designs.Being currently supported within3 D geometr...Comprehensive radiation characteristics of polarized antenna are crucial in creating practical channel coefficients for next generation wireless communication system designs.Being currently supported within3 D geometry-based stochastic channel models(GSCM),field patterns are technically obtained by chamber measurement(or by its best fitting).However,in some channel related performance analysis scenarios,design insight can be crystallized better by starting the derivations with theoretical co-polarization and cross-polarization components.Specifically,these two components are mathematically linked with field patterns through the proposed polarization projection algorithm.In this manuscript,we focus on revealing the transformation criterion of polarization states between the antenna plane and the propagation plane.In practice,it makes retrieving the field patterns by electromagnetic computation possible.Meanwhile,the impact imposed by distinct antenna orientations is geometrically illustrated and consequently incorporated into the proposed algorithm.This will further facilitate flexible performance evaluation of related radio transmission technologies.Our conclusions are verified by the closed-form expression of the dipole field pattern(via an analytical approach) and by chamber measurement results.Moreover,we find that its 2D degenerative case is aligned with the definitions in 3^(rd) generation partnership project(3GPP)technical report 25.996.The most obvious benefit of the proposed algorithm is to significantly reduce the cost on generating channel coefficients in GSCM simulation.展开更多
舟山市鱼山绿色石化基地是我国七大石化基地的重要组成部分,也是打造全国首个绿色发展标杆的石化基地,液化天然气(LNG)码头建设对基地发展十分重要。通过挖掘水域优势,将LNG船舶移动安全区设定为前1 n mile、后0.5 n mile、左右各1倍船...舟山市鱼山绿色石化基地是我国七大石化基地的重要组成部分,也是打造全国首个绿色发展标杆的石化基地,液化天然气(LNG)码头建设对基地发展十分重要。通过挖掘水域优势,将LNG船舶移动安全区设定为前1 n mile、后0.5 n mile、左右各1倍船长(约300 m),给对向船舶预留了约360 m宽的通道,解决了LNG船舶航行过程中对向封控的问题。通过使用代入法,分区段定量分析LNG船舶进出港过程中需要协调避让的船舶数量,形成LNG码头建设后的交通场景。通过对沪舟通道岱山北航道桥、LNG船舶和周围水域的三维建模,采用操纵试验手段,得出LNG专用航道转向点与跨海大桥的安全间距不宜小于6倍船长。展开更多
在船舶大型化的发展以及港口资源日益紧张的趋势下,拖轮调度作为减少港口拥堵与节约港口资源的重要手段,成为当前亟待解决的问题。通过以拖轮空驶燃油成本与拖轮助航燃油成本为目标函数,构建多停泊基地条件下的多目标拖轮调度模型,提出...在船舶大型化的发展以及港口资源日益紧张的趋势下,拖轮调度作为减少港口拥堵与节约港口资源的重要手段,成为当前亟待解决的问题。通过以拖轮空驶燃油成本与拖轮助航燃油成本为目标函数,构建多停泊基地条件下的多目标拖轮调度模型,提出一种混合小生境灰狼算法(Hybrid Niche Grey Wolf Optimization,HNGWO)进行求解,针对拖轮调度问题的整数规划特点引入交叉修正更新策略,以加强算法的收敛性能,最后分别采用CPLEX、GA、PSO、GWO、HNGWO对多规模算例的求解结果进行对比分析。结果表明,HNGWO相比于GA、PSO的最优值平均优化比例可达5.07%,相比于GWO的收敛速度平均优化比例为13.23%,并输出中等规模下的收敛曲线与最优调度方案甘特图,直观展示了改进算法的求解效果与收敛速度,为提高港口通行效率与经济效益提供了参考方案。展开更多
文摘The body channel based wireless power transfer(BC-WPT)method utilizes the human body as the medium to transfer power for bioelectronics,which can achieve a lower transmission loss due to its higher conductivity.However,except for the channel length,different on-body loca-tions of the transmitter and receiver also influence the power supply performance.This paper fo-cuses on the wrist-to-forehead path to show the potential of BC-WPT for the brain bioelectronics such as the brain computer interface device.The channel characteristics from 10 MHz to 60 MHz are measured by a vector network analyzer(VNA)and a prototype BC-WPT system with differ-ent copper electrodes and the lowest power loss locates between-22 dB and-33 dB.Furthermore,the minimum path loss limit is simulated in Advanced Design System(ADS)software and the low-est optimum path loss can reach nearly-13 dB.Finally,a rectifier circuit is also built at the receiv-er side to harvest d.c.voltage.The results show that the open-circuit voltage(OCV)can reach 1.75 V with the transmitter of 50Ωoutput impedance supplying 5V_(pp)sine voltage at 60 MHz when adopt-ing 1 cm-diameter circular electrodes.
基金supported by National Basic Research Program of China (NO 2012CB316002)China’s 863 Project (NO 2014AA01A703)+2 种基金National Major Projec (NO. 2014ZX03003002-002)Program for New Century Excellent Talents in University (NCET-13-0321)Tsinghua University Initiative Scientific Research Program (2011THZ02-2)
文摘It is extensively approved that Channel State Information(CSI) plays an important role for synergetic transmission and interference management. However, pilot overhead to obtain CSI with enough precision is a significant issue for wireless communication networks with massive antennas and ultra-dense cell. This paper proposes a learning- based channel model, which can estimate, refine, and manage CSI for a synergetic transmission system. It decomposes the channel impulse response into multiple paths, and uses a learning-based algorithm to estimate paths' parameters without notable degradation caused by sparse pilots. Both indoor measurement and outdoor measurement are conducted to verify the feasibility of the proposed channel model preliminarily.
基金supported in part by the National Natural Science Foundation of China under Grant 61622101 and Grant 61571020National Science and Technology Major Project under Grant 2018ZX03001031
文摘A more general narrowband regular-shaped geometry-based statistical model(RS-GBSM) combined with the line of sight(LoS) and single bounce(SB) rays for unmanned aerial vehicle(UAV) multiple-input multiple-output(MIMO) channel is proposed in this paper. The channel characteristics, including space-time correlation function(STCF), Doppler power spectral density(DPSD), level crossing rate(LCR) and average fade duration(AFD), are derived based on the single sphere reference model for a non-isotropic environment. The corresponding sum-of-sinusoids(SoS) simulation models including both the deterministic model and statistical model with finite scatterers are also proposed for practicable implementation. The simulation results illustrate that the simulation models well reproduce the channel characteristics of the single sphere reference model with sufficient simulation scatterers. And the statistical model has a better approximation of the reference model in comparison with the deterministic one when the simulation trials of the stochastic model are sufficient. The effects of the parameters such as flight height, moving direction and Rice factor on the characteristics are also studied.
文摘A multistandard software-defined radio base station must perform non-uniform channelization of multiplexed frequency bands. Non-uniform channelization accounts for a significant portion of the digital signal processing workload in the base station receiver and can be difficult to realize in a physical implementation. In non-uniform channelization methods based on generalized DFT filter banks, large prototype filter orders are a significant issue for implementation. In this paper, a multistage filter design is applied to two different non-uniform generalized DFT-based channelizers in order to reduce their filter orders. To evaluate the approach, a TETRA and TEDS base station is used. Experimental results show that the new multistage design reduces both the number of coefficients and operations and leads to a more feasible design and practical physical implementation.
基金Supported by the National Major R&D Program of China (No. 2009ZX03003-008)
文摘Spectrum sensing is one of the key technologies in Cognitive Radios(CRs).Previous works are accomplished under simple channel models,which may lead to unreliable results when it applied to the over-the-air systems.In this paper,we investigate the performance of a Multi-Resolution Spectrum Sensing(MRSS) algorithm under measurement-based channel models in China.MRSS is a wavelet based algorithm which is suitable for non-stationary,wideband signal analysis.Using statistical mod-eling,measurement-based channel models are presented under typical urban and suburban scenarios in Shanghai,China.Then,the performance of the MRSS algorithm is evaluated under the measure-ment-based channel models.Simulation results show that,using MRSS,the performance is always better in the scenarios where Line-Of-Sight(LOS) path exist;also,in LOS scenarios,rich scattering effect helps to increase the performance.
基金supported in part by the Natural Science Basic Research Plan in Shaanxi Province(No.2015JQ6221,No. 2015JQ6259,No.2015JM6341)the Fundamental Research Funds for the Central Universities(No.JB140109)+8 种基金the National Natural Science Foundation of China(No. 61401321,No.61372067)the National Hightech R&D Program of China(No. 2014AA01A704,No.2015AA7124058)the National Basic Research Program of China(No.2014CB340206)the National Key Technology R&D Program of China(No. 2012BAH16B00)the Next Generation Internet Program of China(No.CNGI1203003)the Research Culture Funds of Xi'an University of Science and Technology(No.201357)the Open Project of State Key Laboratory of Integrated Service Networks(No.ISN1601)the Open Research Fund of National Mobile Communications Research Laboratory (No.2015D01)the Science and Technology R&D Program of Shaanxi Province(No. 2014KJXX-49)
文摘Comprehensive radiation characteristics of polarized antenna are crucial in creating practical channel coefficients for next generation wireless communication system designs.Being currently supported within3 D geometry-based stochastic channel models(GSCM),field patterns are technically obtained by chamber measurement(or by its best fitting).However,in some channel related performance analysis scenarios,design insight can be crystallized better by starting the derivations with theoretical co-polarization and cross-polarization components.Specifically,these two components are mathematically linked with field patterns through the proposed polarization projection algorithm.In this manuscript,we focus on revealing the transformation criterion of polarization states between the antenna plane and the propagation plane.In practice,it makes retrieving the field patterns by electromagnetic computation possible.Meanwhile,the impact imposed by distinct antenna orientations is geometrically illustrated and consequently incorporated into the proposed algorithm.This will further facilitate flexible performance evaluation of related radio transmission technologies.Our conclusions are verified by the closed-form expression of the dipole field pattern(via an analytical approach) and by chamber measurement results.Moreover,we find that its 2D degenerative case is aligned with the definitions in 3^(rd) generation partnership project(3GPP)technical report 25.996.The most obvious benefit of the proposed algorithm is to significantly reduce the cost on generating channel coefficients in GSCM simulation.
文摘舟山市鱼山绿色石化基地是我国七大石化基地的重要组成部分,也是打造全国首个绿色发展标杆的石化基地,液化天然气(LNG)码头建设对基地发展十分重要。通过挖掘水域优势,将LNG船舶移动安全区设定为前1 n mile、后0.5 n mile、左右各1倍船长(约300 m),给对向船舶预留了约360 m宽的通道,解决了LNG船舶航行过程中对向封控的问题。通过使用代入法,分区段定量分析LNG船舶进出港过程中需要协调避让的船舶数量,形成LNG码头建设后的交通场景。通过对沪舟通道岱山北航道桥、LNG船舶和周围水域的三维建模,采用操纵试验手段,得出LNG专用航道转向点与跨海大桥的安全间距不宜小于6倍船长。
文摘在船舶大型化的发展以及港口资源日益紧张的趋势下,拖轮调度作为减少港口拥堵与节约港口资源的重要手段,成为当前亟待解决的问题。通过以拖轮空驶燃油成本与拖轮助航燃油成本为目标函数,构建多停泊基地条件下的多目标拖轮调度模型,提出一种混合小生境灰狼算法(Hybrid Niche Grey Wolf Optimization,HNGWO)进行求解,针对拖轮调度问题的整数规划特点引入交叉修正更新策略,以加强算法的收敛性能,最后分别采用CPLEX、GA、PSO、GWO、HNGWO对多规模算例的求解结果进行对比分析。结果表明,HNGWO相比于GA、PSO的最优值平均优化比例可达5.07%,相比于GWO的收敛速度平均优化比例为13.23%,并输出中等规模下的收敛曲线与最优调度方案甘特图,直观展示了改进算法的求解效果与收敛速度,为提高港口通行效率与经济效益提供了参考方案。
