基于通信的列车自动控制(communication based train control, CBTC)系统采用地铁长期演进系统(long term evolution-metro, LTE-M)完成车地之间的数据通信,并限定数据在较低的时延内完成传输.将CBTC系统中列车终端接入基站的通信模型...基于通信的列车自动控制(communication based train control, CBTC)系统采用地铁长期演进系统(long term evolution-metro, LTE-M)完成车地之间的数据通信,并限定数据在较低的时延内完成传输.将CBTC系统中列车终端接入基站的通信模型化为排队论体系中的M/M/1/m/m模型,推导LTE-M应用于CBTC时数据传输时延的概率预测方法,并给出满足CBTC需求的相关条件,为LTE-M系统的可靠性设计提供参考.展开更多
A propagation measurement campaign was performed at the 10 th floor corridor of Xingjian Building,Shanghai University,China.The channel was sounded by pseudo noise( PN) sequence at carrier frequencies of 400-and 2600-...A propagation measurement campaign was performed at the 10 th floor corridor of Xingjian Building,Shanghai University,China.The channel was sounded by pseudo noise( PN) sequence at carrier frequencies of 400-and 2600-MHz respectively.In order to obtain large scale and small scale propagation characteristics in the corridor,the receiver was moved along the corridor every 1.02 meter to record the impulse response.More than 280,000 impulse responses were recorded in the campaign.This work first describes the principle of the measurement,and then how the recorded raw data are processed.The results show that path loss exponent is related to frequency.The relationship between the root-mean squared( RMS) delay spread and the T-R separation distance is analyzed.The RMS delay spread and the mean excess delay spread against path loss are also given,which explain why the 2600 MHz RMS delay spread is larger than that of 400 MHz.展开更多
In this paper,a novel M-ary chirp modulation scheme is proposed on the basis of the energy concen-tration property of chirp signals in fractional domain.In the proposed scheme,chirp signals with diferent phases are mu...In this paper,a novel M-ary chirp modulation scheme is proposed on the basis of the energy concen-tration property of chirp signals in fractional domain.In the proposed scheme,chirp signals with diferent phases are multiplexed in the same time frequency bandwidth through reverse chirp rate to increase information rate.In addition,fractional filters based on fractional Fourier transform(FRFT)are designed to separate chirp signals of diferent chirp-rates in the receiver.Moreover,the theoretical performance of fractional filters and the error probability of M-ary chirp system are derived.Both theoretical analysis and simulation prove that the proposed scheme outperforms M-ary quadrature amplitude modulation(QAM)system in the anti-noise performance.展开更多
文摘基于通信的列车自动控制(communication based train control, CBTC)系统采用地铁长期演进系统(long term evolution-metro, LTE-M)完成车地之间的数据通信,并限定数据在较低的时延内完成传输.将CBTC系统中列车终端接入基站的通信模型化为排队论体系中的M/M/1/m/m模型,推导LTE-M应用于CBTC时数据传输时延的概率预测方法,并给出满足CBTC需求的相关条件,为LTE-M系统的可靠性设计提供参考.
基金Supported by the National Natural Science Foundation of China(No.61132003,61171086,61501186)Shanghai Natural Science Foundation under Grant(No.14ZR1415100)
文摘A propagation measurement campaign was performed at the 10 th floor corridor of Xingjian Building,Shanghai University,China.The channel was sounded by pseudo noise( PN) sequence at carrier frequencies of 400-and 2600-MHz respectively.In order to obtain large scale and small scale propagation characteristics in the corridor,the receiver was moved along the corridor every 1.02 meter to record the impulse response.More than 280,000 impulse responses were recorded in the campaign.This work first describes the principle of the measurement,and then how the recorded raw data are processed.The results show that path loss exponent is related to frequency.The relationship between the root-mean squared( RMS) delay spread and the T-R separation distance is analyzed.The RMS delay spread and the mean excess delay spread against path loss are also given,which explain why the 2600 MHz RMS delay spread is larger than that of 400 MHz.
基金the National Natural Science Founda-tion of China(No.61571282)the Open Project Program of the State Key Laboratory of Rail Traffic Control and Safety(No.RCS2017K012)。
文摘In this paper,a novel M-ary chirp modulation scheme is proposed on the basis of the energy concen-tration property of chirp signals in fractional domain.In the proposed scheme,chirp signals with diferent phases are multiplexed in the same time frequency bandwidth through reverse chirp rate to increase information rate.In addition,fractional filters based on fractional Fourier transform(FRFT)are designed to separate chirp signals of diferent chirp-rates in the receiver.Moreover,the theoretical performance of fractional filters and the error probability of M-ary chirp system are derived.Both theoretical analysis and simulation prove that the proposed scheme outperforms M-ary quadrature amplitude modulation(QAM)system in the anti-noise performance.
