This letter deals with the frequency domain Blind Source Separation of Convolutive Mixtures (CMBSS). From the frequency representation of the "overlap and save", a Weighted General Discrete Fourier Transform...This letter deals with the frequency domain Blind Source Separation of Convolutive Mixtures (CMBSS). From the frequency representation of the "overlap and save", a Weighted General Discrete Fourier Transform (WGDFT) is derived to replace the traditional Discrete Fourier Transform (DFT). The mixing matrix on each frequency bin could be estimated more precisely from WGDFT coefficients than from DFT coefficients, which improves separation performance. Simulation results verify the validity of WGDFT for frequency domain blind source separation of convolutive mixtures.展开更多
This paper proposes a systematic design method of overlap frequency domain equalization(FDE) for single carrier (SC) transmission without a guard interval (GI).Based on the analysis of signal-to-interference-plus-nois...This paper proposes a systematic design method of overlap frequency domain equalization(FDE) for single carrier (SC) transmission without a guard interval (GI).Based on the analysis of signal-to-interference-plus-noise ratio (SINR) of the equalizer output for each symbol,the authors adaptivelydetermine the block of the overlap FDE,where the block is defined as a set of symbols at the equalizeroutput with sufficiently low error rate,for a certain fixed sliding window size,which corresponds toa fast Fourier transform (FFT) window size.The proposed method takes advantage of the fact thatthe utility part of the equalized signal is localized around the center of the FFT window.In addition,the authors also propose to adjust the block size in order to control the computational complexity ofthe equalization per processed sample associating with the average bit error rate (BER) of the system.Simulation results show that the proposed scheme can achieve comparable BER performance to theconventional SC-FDE scheme with sufficient GI insertion for both the coded and uncoded cases withvarious modulation levels,while requiring lower computational complexity compared to the SC overlapFDE transmission with the fixed block.展开更多
Based on the Overlapped Multiplexing Principle[12],a frequency domain OVFDM(Overlapped Frequency Domain Multiplexing) Coding is proposed.By the data weighted shift overlapped version of any band-limited Multiplexing T...Based on the Overlapped Multiplexing Principle[12],a frequency domain OVFDM(Overlapped Frequency Domain Multiplexing) Coding is proposed.By the data weighted shift overlapped version of any band-limited Multiplexing Transfer Function H(f) the coding gain and spectral efficiency are both achieved.The heavier the overlap of the data weighted Multiplexing Transfer Function H(f),the higher the coding gain and spectral efficiency as well as the closer the output to the optimum complex Gaussian distribution.The bit error probability performance is estimated.The time domain OVTDM(Overlapped Time Domain Multiplexing) Coding,the dual of OVFDM in time domain is incidentally proposed as well.Both theoretical analysis and testified simulations show that OVFDM(OVTDM) is suitable for high spectral efficiency application and its spectral efficiency is only roughly linear to SNR rather than the well-known logarithm to SNR.展开更多
A method utilizing single channel recordings to blindly separate the multicomponents overlapped in time and frequency domains is proposed in this paper. Based on the time varying AR model, the instantaneous frequency ...A method utilizing single channel recordings to blindly separate the multicomponents overlapped in time and frequency domains is proposed in this paper. Based on the time varying AR model, the instantaneous frequency and amplitude of each signal component are estimated respectively, thus the signal component separation is achieved. By using prolate spheroidal sequence as basis functions to expand the time varying parameters of the AR model, the method turns the problem of linear time varying parameters estimation to a linear time invariant parameter estimation problem, then the parameters are estimated by a recursive algorithm. The computation of this method is simple, and no prior knowledge of the signals is needed. Simulation results demonstrate validity and excellent performance of this method.展开更多
Non-orthogonal time-frequency division multiplexing （NTFDM） transmission scheme has been proposed to further improve the bandwidth efficiency and overcome the drawbacks of the conventional orthogonal frequency divis...Non-orthogonal time-frequency division multiplexing （NTFDM） transmission scheme has been proposed to further improve the bandwidth efficiency and overcome the drawbacks of the conventional orthogonal frequency division multiplexing （OFDM） method. Based on such approach, the fast signal detection algorithm, semidefinite programming （SDP） detection, has been studied. As the coefficient matrix tends to be ill conditioned, the modified SDP algorithm combined with successive interference cancellation （SIC） has been developed. The improved algorithm is a good tradeoff between performance and detection complexity. Simulation results show that the proposed algorithm can achieve better performance than cutting plane aided SDP method.展开更多
In this paper,RF performance analysis of In As-based double gate（DG）tunnel field effect transistors（TFETs）is investigated in both qualitative and quantitative fashion.This investigation is carried out by varying t...In this paper,RF performance analysis of In As-based double gate（DG）tunnel field effect transistors（TFETs）is investigated in both qualitative and quantitative fashion.This investigation is carried out by varying the geometrical and doping parameters of TFETs to extract various RF parameters,unity gain cut-off frequency（f_t）,maximum oscillation frequency（f_（max））,intrinsic gain and admittance（Y）parameters.An asymmetric gate oxide is introduced in the gate-drain overlap and compared with that of DG TFETs.Higher ON-current（ION）of about 0.2 mA and less leakage current（IOFF）of 29 f A is achieved for DG TFET with gate-drain overlap.Due to increase in transconductance（g_m）,higher ft and intrinsic gain is attained for DG TFET with gate-drain overlap.Higher f_（max） of 985 GHz is obtained for drain doping of 5×10^（17）cm^（-3） because of the reduced gate-drain capacitance（C_（gd））with DG TFET with gate-drain overlap.In terms of Y-parameters,gate oxide thickness variation offers better performance due to the reduced values of Cgd.A second order numerical polynomial model is generated for all the RF responses as a function of geometrical and doping parameters.The simulation results are compared with this numerical model where the predicted values match with the simulated values.展开更多
基金the grant from the Ph.D. Programs Foun-dation of Ministry of Education of China (No. 20060280003)the Shanghai Leading Academic Dis-cipline Project (Project No.T0102).
文摘This letter deals with the frequency domain Blind Source Separation of Convolutive Mixtures (CMBSS). From the frequency representation of the "overlap and save", a Weighted General Discrete Fourier Transform (WGDFT) is derived to replace the traditional Discrete Fourier Transform (DFT). The mixing matrix on each frequency bin could be estimated more precisely from WGDFT coefficients than from DFT coefficients, which improves separation performance. Simulation results verify the validity of WGDFT for frequency domain blind source separation of convolutive mixtures.
基金supported in part by Grant-in-Aid for Scientific Research No. 21760289 from the Ministry of Education, Science, Sport and Culture of Japanby the KMRC R&D Grant for Mobile Wireless from Kinki Mobile Radio Center, Foundation, Japan
文摘This paper proposes a systematic design method of overlap frequency domain equalization(FDE) for single carrier (SC) transmission without a guard interval (GI).Based on the analysis of signal-to-interference-plus-noise ratio (SINR) of the equalizer output for each symbol,the authors adaptivelydetermine the block of the overlap FDE,where the block is defined as a set of symbols at the equalizeroutput with sufficiently low error rate,for a certain fixed sliding window size,which corresponds toa fast Fourier transform (FFT) window size.The proposed method takes advantage of the fact thatthe utility part of the equalized signal is localized around the center of the FFT window.In addition,the authors also propose to adjust the block size in order to control the computational complexity ofthe equalization per processed sample associating with the average bit error rate (BER) of the system.Simulation results show that the proposed scheme can achieve comparable BER performance to theconventional SC-FDE scheme with sufficient GI insertion for both the coded and uncoded cases withvarious modulation levels,while requiring lower computational complexity compared to the SC overlapFDE transmission with the fixed block.
基金The NNSF(National Nature Science Foundation)of China for their continuously long term support by key projects
文摘Based on the Overlapped Multiplexing Principle[12],a frequency domain OVFDM(Overlapped Frequency Domain Multiplexing) Coding is proposed.By the data weighted shift overlapped version of any band-limited Multiplexing Transfer Function H(f) the coding gain and spectral efficiency are both achieved.The heavier the overlap of the data weighted Multiplexing Transfer Function H(f),the higher the coding gain and spectral efficiency as well as the closer the output to the optimum complex Gaussian distribution.The bit error probability performance is estimated.The time domain OVTDM(Overlapped Time Domain Multiplexing) Coding,the dual of OVFDM in time domain is incidentally proposed as well.Both theoretical analysis and testified simulations show that OVFDM(OVTDM) is suitable for high spectral efficiency application and its spectral efficiency is only roughly linear to SNR rather than the well-known logarithm to SNR.
基金Supported by the Program for New Century Excellent Talents in University, Ministry of Education, China (Grant No. NCET-05-0803)
文摘A method utilizing single channel recordings to blindly separate the multicomponents overlapped in time and frequency domains is proposed in this paper. Based on the time varying AR model, the instantaneous frequency and amplitude of each signal component are estimated respectively, thus the signal component separation is achieved. By using prolate spheroidal sequence as basis functions to expand the time varying parameters of the AR model, the method turns the problem of linear time varying parameters estimation to a linear time invariant parameter estimation problem, then the parameters are estimated by a recursive algorithm. The computation of this method is simple, and no prior knowledge of the signals is needed. Simulation results demonstrate validity and excellent performance of this method.
基金the National Natural Science Foundation of China (90604035)
文摘Non-orthogonal time-frequency division multiplexing （NTFDM） transmission scheme has been proposed to further improve the bandwidth efficiency and overcome the drawbacks of the conventional orthogonal frequency division multiplexing （OFDM） method. Based on such approach, the fast signal detection algorithm, semidefinite programming （SDP） detection, has been studied. As the coefficient matrix tends to be ill conditioned, the modified SDP algorithm combined with successive interference cancellation （SIC） has been developed. The improved algorithm is a good tradeoff between performance and detection complexity. Simulation results show that the proposed algorithm can achieve better performance than cutting plane aided SDP method.
基金Project supported by the Department of Science and Technology,Government of India under SERB Scheme(No.SERB/F/2660)
文摘In this paper,RF performance analysis of In As-based double gate（DG）tunnel field effect transistors（TFETs）is investigated in both qualitative and quantitative fashion.This investigation is carried out by varying the geometrical and doping parameters of TFETs to extract various RF parameters,unity gain cut-off frequency（f_t）,maximum oscillation frequency（f_（max））,intrinsic gain and admittance（Y）parameters.An asymmetric gate oxide is introduced in the gate-drain overlap and compared with that of DG TFETs.Higher ON-current（ION）of about 0.2 mA and less leakage current（IOFF）of 29 f A is achieved for DG TFET with gate-drain overlap.Due to increase in transconductance（g_m）,higher ft and intrinsic gain is attained for DG TFET with gate-drain overlap.Higher f_（max） of 985 GHz is obtained for drain doping of 5×10^（17）cm^（-3） because of the reduced gate-drain capacitance（C_（gd））with DG TFET with gate-drain overlap.In terms of Y-parameters,gate oxide thickness variation offers better performance due to the reduced values of Cgd.A second order numerical polynomial model is generated for all the RF responses as a function of geometrical and doping parameters.The simulation results are compared with this numerical model where the predicted values match with the simulated values.
