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Adaptive Antenna-Activation Based Beamforming for Large-Scale MIMO Communication Systems of High Speed Railway 被引量:3
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作者 Meng Cheng Shaoshi Yang Xuming Fang 《China Communications》 SCIE CSCD 2016年第9期12-23,共12页
Large-scale array aided beamforming improves the spectral efficiency(SE) as a benefit of high angular resolution.When dual-beam downlink beamforming is applied to the train moving towards cell edge,the inter-beam ambi... Large-scale array aided beamforming improves the spectral efficiency(SE) as a benefit of high angular resolution.When dual-beam downlink beamforming is applied to the train moving towards cell edge,the inter-beam ambiguity(IBA) increases as the directional difference between beams becomes smaller.An adaptive antenna activation based beamforming scheme was proposed to mitigate IBA.In the district near the base station(BS),all antenna elements(AEs) were activated to generate two beams.As the distance from the train to the BS increased,only the minimum number of AEs satisfying the resolution criterion would be activated.At the cell edge,one beam was switched off due to intolerable IBA.The proposed scheme can achieve SE gain to the non-adaptive scheme and show more robustness against the direction-of-arrival(DOA) estimation error. 展开更多
关键词 wireless communications adap- tive antenna activation large-scale antenna array downlink beamforming high speed railway
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Analysis of OFDM Applied to Powerline High Speed Digital Communication 被引量:1
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作者 庄建 杨公训 《Journal of China University of Mining and Technology》 2003年第2期174-178,共5页
The low voltage powerline is becoming a powerful solution to home network, building automation, and internet access as a result of its wide distribution, easy access and little maintenance. The character of powerline ... The low voltage powerline is becoming a powerful solution to home network, building automation, and internet access as a result of its wide distribution, easy access and little maintenance. The character of powerline channel is very complicated because it is an open net. This article analysed the character of the powerline channel,introduced the basics of OFDM(Orthogonal Frequency Division Multiplexing), and studied the OFDM applied into powerline high speed digital communication. 展开更多
关键词 powerline carrier communication OFDM high speed digital communication
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Guest editorial: special issue on high mobility wireless communications 被引量:2
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作者 Pingzhi FAN Erdal PANAYIRCI +2 位作者 Ping LI Chengxiang WANG Vahid TAROKH 《Journal of Modern Transportation》 2012年第4期197-198,共2页
The high-speed railway and high-way networks are now expanding at a phenomenal speed in Chinaand in many other parts of the world. The related broadband wireless communication over high-speed trains and highway vehicl... The high-speed railway and high-way networks are now expanding at a phenomenal speed in Chinaand in many other parts of the world. The related broadband wireless communication over high-speed trains and highway vehicles is a very challenging task due to hostile transmission channel conditions. The demand for such services is growing rapidly, following the proliferation of laptop/tablet computers and smart phones. This motivates the research on wireless communications in the high mobility environments. 展开更多
关键词 high mobility wireless communications high speed trains (HSTs)
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High-Performance Network Communications for CSCW
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作者 宋军 顾冠群 《Journal of Southeast University(English Edition)》 EI CAS 1996年第2期7-12,共6页
Computer supported cooperative work as a new multi disciplinary research area, brings a lot of new challenges for the computer technologies. Having analyzed the CSCW applications by using the groupware space time mat... Computer supported cooperative work as a new multi disciplinary research area, brings a lot of new challenges for the computer technologies. Having analyzed the CSCW applications by using the groupware space time matrix, we conclude that the communicatio 展开更多
关键词 CSCW high speed NETWORK MULTIMEDIA high performance communicationS platform
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8×10Gb/s High Speed WDM Transmission Experiment over 80km Standard Single-Mode Fiber
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作者 董毅 《High Technology Letters》 EI CAS 1999年第2期4-6,共3页
A WDM transmission experiment of 8×10Gb/s over 80km standard single mode fiber(SSMF) using a LiNbO 3 modulator was reported in this paper. For each WDM channel, the PIN receiver sensitivity better than -16.0dBm a... A WDM transmission experiment of 8×10Gb/s over 80km standard single mode fiber(SSMF) using a LiNbO 3 modulator was reported in this paper. For each WDM channel, the PIN receiver sensitivity better than -16.0dBm and the power penalty less than 1.5dB at 10 -10 BER were obtained. The variation of receiver sensitivity for eight channels was less than 1.0dB. The impact of the channel spacing and the polarization stability were also discussed in this paper. 展开更多
关键词 high speed WAVELENGTH DIVISION Multiplexing(WDM) Optical communication
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50 GHz Spaced 4 ×40 Gbit/s WDM Transmission over 700 km Using 6 ps Bandlimited RZ Signals
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作者 Mousaab M. Nahas 《Optics and Photonics Journal》 2011年第3期137-141,共5页
In this paper, we present 50 GHz spaced 4 ×40 Gbit/s WDM transmission over 700 km using SMF-based Effective Area Enlarged Positive Dispersion Fiber in a recirculating loop. The paper uses bandlimited RZ signals a... In this paper, we present 50 GHz spaced 4 ×40 Gbit/s WDM transmission over 700 km using SMF-based Effective Area Enlarged Positive Dispersion Fiber in a recirculating loop. The paper uses bandlimited RZ signals and shows that transmission distance of 700 km can be achieved with BER ≤ 10-9 using 6 ps pulsewidth for each data signal. To attain this, optical filters with sharp transmission characteristics are used in both transmitter and receiver. The results demonstrated in this paper are based on simulation, and the author believes the propagation distance reached in the paper is the longest distance achieved for such system. 展开更多
关键词 Telecommunications Fiber Optics communications WAVELENGTH DIVISION MULTIPLEXING (WDM) OPTICAL Time DIVISION MULTIPLEXING (OTDM) high speed OPTICAL Transmission
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A Facile Strategy for Intrinsic Low-Dk and Low-Df Polyimides Enabled by Spirobifluorene Groups 被引量:1
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作者 Wan-Yi Tan Ling-Feng Jian +9 位作者 Wei-Peng Chen Yong-Wen Zhang Xiao-Chuang Lu Wan-Jun Huang Ji-Sheng Zhang Jing-Wu Wu Jun-Li Feng Yi-Dong Liu Ting-Ting Cui Yong-Gang Min 《Chinese Journal of Polymer Science》 SCIE EI CAS CSCD 2023年第2期288-296,共9页
Modified polyimides(MPIs)show great potential towards 5G communication applications,due to its excellent thermal stability,mechanical property and chemical stability as compared to most of polymers.Introducing fluorid... Modified polyimides(MPIs)show great potential towards 5G communication applications,due to its excellent thermal stability,mechanical property and chemical stability as compared to most of polymers.Introducing fluoride groups or porous structure is favorable to ultra-low dielectric constant(D_(k))and dielectric loss(D_(f)).However,the cost of the fluorinated MPIs is high and their synthetic processes are complicated,and porous MPIs suffer poor mechanical properties.Also,increasing the fraction of free volume is a very effective way to lower D_(k)through introducing more ultra-low-D_(k)air component.However,most of this kind of MPIs lag far behind the fluorinated MPIs and the porous MPIs in terms of ultra-low D_(f),hindering the application of MPIs in high-speed communication devices.Thus,it is highly desirable to develop intrinsic ultra-low-D_(k)/D_(f)MPIs at high frequency with less fluoric groups and nonporous structure.Herein,we introduce a facile and effective strategy to lower D_(k)and D_(f)through introducing rigid and large sterically hindered aromatic groups into MPIs.On the one hand,their large steric hindrance effect leads to low D_(k)by increasing intrinsic free volume.On the other hand,the resulting highly stiff polymer chain and strong intermolecular interaction are favorable to reduce D_(f)by inhibiting dipole orientations.Based on this strategy,the spirobifluorene groups are preferred.The as-prepared MPIs show excellent dielectric performance with low D_(k)of 2.74–2.76 and low D_(f)of 0.00599 at 10 GHz,to some extent,exceeding the multiple fluorinated MPI with D_(k)/D_(f)of 2.67/0.00663 at 10 GHz. 展开更多
关键词 POLYIMIDE high speed communication Low dielectric constant Low dielectric loss
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