针对现有基于最小均方误差准则的全双工射频域自干扰对消算法存在收敛速度与干扰对消比相互制约的矛盾,提出一种改进时变步长归一化最小均方算法。该算法通过建立最小均方误差步长因子与改进时变sigmod函数的非线性关系,利用实时误差信...针对现有基于最小均方误差准则的全双工射频域自干扰对消算法存在收敛速度与干扰对消比相互制约的矛盾,提出一种改进时变步长归一化最小均方算法。该算法通过建立最小均方误差步长因子与改进时变sigmod函数的非线性关系,利用实时误差信号自相关和时间参量t协同控制步长因子μ(t),较好的兼顾了收敛速度与干扰对消比。分析与仿真表明:在干信比为80 d B、步进间隔Δt=1/32 ms、信噪比Eb/N0=10 d B的2FSK全双工系统模型下,该算法能够实现88 d B的自干扰消除高出同类算法至少1.5 d B且收敛速度和抗突发干扰能力提升显著。展开更多
The free-surface Green function method is widely used in solving the radiation or diffraction problems caused by a ship or ocean structure oscillating on the waves. In the context of inviscid potential flow, hydrodyna...The free-surface Green function method is widely used in solving the radiation or diffraction problems caused by a ship or ocean structure oscillating on the waves. In the context of inviscid potential flow, hydrodynamic problems such as multi-body interaction and tank side wall effect cannot be properly dealt with based on the traditional free-surface frequency domain Green function method, in which the water viscosity is omitted and the energy dissipation effect is absent. In this paper, an open-sea Green function with viscous dissipation was presented within the theory ofvisco-potential flow. Then the tank Green function with a partial reflection from the side walls in wave tanks was formulated as a formal sum of open-sea Green functions representing the infinite images between two parallel side walls of the source in the tank. The new far-field characteristics of the tank Green function is vitally important fur improving the validity of side-wall effects evaluation, which can be used in supervising the tank model tests.展开更多
Wireless location technology is used to locate,track and monitor the location of given target using devices such as the radio frequency identification(RFID) based on WiFi technology and the sensors. And such applicati...Wireless location technology is used to locate,track and monitor the location of given target using devices such as the radio frequency identification(RFID) based on WiFi technology and the sensors. And such applications as long term evolution(LTE) ,wireless local area networks(WLAN) ,RFID and location based service(LBS) are essential in today's wireless communications industry. In this paper,both wireless location technology and its application are proposed,where our experimental research results and theoretical innovation are included.展开更多
This paper proposes a time-domain clustered transmitter power adaptation scheme for orthogonal frequency division multiplexing (OFDM) system, which can significantly reduce the feedback amount during power adaptation ...This paper proposes a time-domain clustered transmitter power adaptation scheme for orthogonal frequency division multiplexing (OFDM) system, which can significantly reduce the feedback amount during power adaptation comparison with conventional frequency-domain adaptation schemes. It was found that the cluster size plays an important role on the adaptation performance, especially for the vehicular environment. Simulation results showed that using Lagrange interpolation to obtain an explicit curve of Doppler frequency vs cluster size yields good trade-off between the resulted bit error rate (BER) and the amount of feedback.展开更多
The authors state briefly the possibility of various simulators to handle propagation of electromagnetic waves along some interconnections, in 3D RF （Radio Frequency） circuits. The studies are first derived in the t...The authors state briefly the possibility of various simulators to handle propagation of electromagnetic waves along some interconnections, in 3D RF （Radio Frequency） circuits. The studies are first derived in the time domain： a Finite-Difference Time-Domain method is applied, taking spectra via FFTs （Fast Fourier Transform） as post-processors. Electric and magnetic field distributions, pulse propagations along stripline structures or vias are highlighted. The scattering parameters for various cases are extracted and compared. Some original issue of this work is an insight on crosstalk or shielding phenomena between lines.展开更多
Frequency-domain terahertz transmission spectra of Mn3 and Mn12 single molecule magnets （SMMs） have been measured at different temperatures, and hence the anisotropic parameters O2 and D4 of the spin Hamiltonian H =...Frequency-domain terahertz transmission spectra of Mn3 and Mn12 single molecule magnets （SMMs） have been measured at different temperatures, and hence the anisotropic parameters O2 and D4 of the spin Hamiltonian H = D2Sz^2 ＋ D4Sz^4 have been calculated. For Mn12 SMM, D2=-10.9 GHz and D4=-2.59×10^-2 GHz, while for Mn3 SMM, D2=-22.0 GHz and D4 can be con- sidered negligible. This suggests Mn3 SMM can be considered as a simpler and more suitable candidate for magnetic quantum tunneling research.展开更多
文摘针对现有基于最小均方误差准则的全双工射频域自干扰对消算法存在收敛速度与干扰对消比相互制约的矛盾,提出一种改进时变步长归一化最小均方算法。该算法通过建立最小均方误差步长因子与改进时变sigmod函数的非线性关系,利用实时误差信号自相关和时间参量t协同控制步长因子μ(t),较好的兼顾了收敛速度与干扰对消比。分析与仿真表明:在干信比为80 d B、步进间隔Δt=1/32 ms、信噪比Eb/N0=10 d B的2FSK全双工系统模型下,该算法能够实现88 d B的自干扰消除高出同类算法至少1.5 d B且收敛速度和抗突发干扰能力提升显著。
基金Supported by NSFC Project(51009037)"111"Program(B07019)
文摘The free-surface Green function method is widely used in solving the radiation or diffraction problems caused by a ship or ocean structure oscillating on the waves. In the context of inviscid potential flow, hydrodynamic problems such as multi-body interaction and tank side wall effect cannot be properly dealt with based on the traditional free-surface frequency domain Green function method, in which the water viscosity is omitted and the energy dissipation effect is absent. In this paper, an open-sea Green function with viscous dissipation was presented within the theory ofvisco-potential flow. Then the tank Green function with a partial reflection from the side walls in wave tanks was formulated as a formal sum of open-sea Green functions representing the infinite images between two parallel side walls of the source in the tank. The new far-field characteristics of the tank Green function is vitally important fur improving the validity of side-wall effects evaluation, which can be used in supervising the tank model tests.
基金National Natural Science Foundation of China ( No.61172073)Open Research Fund of National Mobile Communications Research Laboratory,Southeast University( No.W200906)Fundamental Research Funds for the Central Universities,Beijing Jiaotong University
文摘Wireless location technology is used to locate,track and monitor the location of given target using devices such as the radio frequency identification(RFID) based on WiFi technology and the sensors. And such applications as long term evolution(LTE) ,wireless local area networks(WLAN) ,RFID and location based service(LBS) are essential in today's wireless communications industry. In this paper,both wireless location technology and its application are proposed,where our experimental research results and theoretical innovation are included.
基金Project supported by the Hi-Tech Research and Development Pro-gram (863) of China (No. 2003AA123310), and the National Natural Science Foundation of China (No. 60332030)
文摘This paper proposes a time-domain clustered transmitter power adaptation scheme for orthogonal frequency division multiplexing (OFDM) system, which can significantly reduce the feedback amount during power adaptation comparison with conventional frequency-domain adaptation schemes. It was found that the cluster size plays an important role on the adaptation performance, especially for the vehicular environment. Simulation results showed that using Lagrange interpolation to obtain an explicit curve of Doppler frequency vs cluster size yields good trade-off between the resulted bit error rate (BER) and the amount of feedback.
文摘The authors state briefly the possibility of various simulators to handle propagation of electromagnetic waves along some interconnections, in 3D RF （Radio Frequency） circuits. The studies are first derived in the time domain： a Finite-Difference Time-Domain method is applied, taking spectra via FFTs （Fast Fourier Transform） as post-processors. Electric and magnetic field distributions, pulse propagations along stripline structures or vias are highlighted. The scattering parameters for various cases are extracted and compared. Some original issue of this work is an insight on crosstalk or shielding phenomena between lines.
基金supported by the Science Foundation of the Chinese Academy of Sciences (Grant No. KJCX2-SW-W20)the National Basic Research Program of China (Grant No. 2011CB921702)
文摘Frequency-domain terahertz transmission spectra of Mn3 and Mn12 single molecule magnets （SMMs） have been measured at different temperatures, and hence the anisotropic parameters O2 and D4 of the spin Hamiltonian H = D2Sz^2 ＋ D4Sz^4 have been calculated. For Mn12 SMM, D2=-10.9 GHz and D4=-2.59×10^-2 GHz, while for Mn3 SMM, D2=-22.0 GHz and D4 can be con- sidered negligible. This suggests Mn3 SMM can be considered as a simpler and more suitable candidate for magnetic quantum tunneling research.
