提出一种基于盲信号分离的方法对MIMO信号进行调制识别.该方法对接收信号的相关矩阵作奇异值分解,用于估算发射天线数目,并对信号进行白化.采用特征值矩阵的联合近似对角化(joint approximate diagonalisation of eigen-matrices,JADE)...提出一种基于盲信号分离的方法对MIMO信号进行调制识别.该方法对接收信号的相关矩阵作奇异值分解,用于估算发射天线数目,并对信号进行白化.采用特征值矩阵的联合近似对角化(joint approximate diagonalisation of eigen-matrices,JADE)算法对接收信号进行分离,恢复发送端信号.通过分析信号的频谱特征,提出4个新的特征参数,并结合四阶累积量实现对MIMO体制下6种信号调制方式的识别.识别过程中无需估计载波频率和符号率等参数,具有较强的实用性.仿真结果表明文中提出的方法具有良好的性能.展开更多
Noises always disturb the control effect of an environment test especially in multi-input multi-output(MIMO) systems. If the frequency response function matrices are ill-conditioned, the noises in the driving forces w...Noises always disturb the control effect of an environment test especially in multi-input multi-output(MIMO) systems. If the frequency response function matrices are ill-conditioned, the noises in the driving forces will be amplified and the response spectral lines may awfully exceed their tolerances. Most of the major biases between the response spectra and the reference spectra are produced by the amplified noises. However, ordinary control algorithms can hardly reduce the level of noises. The influences of the noises on both the auto- and cross-power spectra are analyzed in this paper. As a conventional frequency domain method on the inverse problem, the Tikhonov filter is adopted in the environment test to suppress the exceeding spectral lines. By altering regularization parameters gradually, the auto-power spectra can be improved in a closed control loop. Instead of using the traditional way of selecting regularization parameters, we observe the coherence change to estimate noise eliminations. Incidentally, the requirement of coherence control can be realized. The errors of the phase are then studied and a phase control algorithm is introduced at the end as a supplement of cross-power spectra control. The Tikhonov filter and the proposed phase control algorithm are tested numerically and experimentally. The results show that the noises in the vicinity of lightly damped resonant peaks are more stubborn. The response spectra are able to be greatly improved by the combination of these two methods.展开更多
针对未编码的多输入多输出(MIMO,Multi-Input Multi-Output)系统,提出一种复杂度适中的分组全分集全码率(GFDFR,Group-wise Full Diversity Full Rate)空时编码方案。该方案通过在发送端进行天线分组,各组独立编码,减小全分集全码率(FDF...针对未编码的多输入多输出(MIMO,Multi-Input Multi-Output)系统,提出一种复杂度适中的分组全分集全码率(GFDFR,Group-wise Full Diversity Full Rate)空时编码方案。该方案通过在发送端进行天线分组,各组独立编码,减小全分集全码率(FDFR,Full Diversity FullRate)编码块的大小从而降低系统编解码复杂度;在频率选择性信道中,进一步对子载波分组进行独立编码,获得频率分集(或多径分集),以适中的复杂度在不降低系统分集度的情况下保证了信息的全码率传输,是一种在MIMO信道中极具实用价值的空时编码方案。展开更多
An extensive 4 x 4 MIMO channel measurement is carried out at 6. 0-6. 4 GHz under a typical classroom environment with channel sounder based on vector network analyzer. Both LOS and NLOS scenarios are considered. The ...An extensive 4 x 4 MIMO channel measurement is carried out at 6. 0-6. 4 GHz under a typical classroom environment with channel sounder based on vector network analyzer. Both LOS and NLOS scenarios are considered. The results on path loss, delay spread and spatial correlation are presented. The measurement shows that, for corridor coverage, 2x2 MIMO is more economical than 4x4 MIMO due to high correlation. In order to identify the unique characteristics at the high frequency band, the measured channel parameters at 6. 0-6.4 GHz are compared with those at 2. 45 GHz. The comparison shows that the shortened wavelength of this higher frequency band results in a great difference of channel characteristics. Therefore, our measurement results provide new gnidance for the design and development of the system working on 6. 0-6.4 GHz band.展开更多
文摘提出一种基于盲信号分离的方法对MIMO信号进行调制识别.该方法对接收信号的相关矩阵作奇异值分解,用于估算发射天线数目,并对信号进行白化.采用特征值矩阵的联合近似对角化(joint approximate diagonalisation of eigen-matrices,JADE)算法对接收信号进行分离,恢复发送端信号.通过分析信号的频谱特征,提出4个新的特征参数,并结合四阶累积量实现对MIMO体制下6种信号调制方式的识别.识别过程中无需估计载波频率和符号率等参数,具有较强的实用性.仿真结果表明文中提出的方法具有良好的性能.
基金supported by the Fundamental Research Funds for the Central Universities (No. NS2015008)the corresponding work was performed in the State Key Laboratory of Mechanics and Control of Mechanical Structures
文摘Noises always disturb the control effect of an environment test especially in multi-input multi-output(MIMO) systems. If the frequency response function matrices are ill-conditioned, the noises in the driving forces will be amplified and the response spectral lines may awfully exceed their tolerances. Most of the major biases between the response spectra and the reference spectra are produced by the amplified noises. However, ordinary control algorithms can hardly reduce the level of noises. The influences of the noises on both the auto- and cross-power spectra are analyzed in this paper. As a conventional frequency domain method on the inverse problem, the Tikhonov filter is adopted in the environment test to suppress the exceeding spectral lines. By altering regularization parameters gradually, the auto-power spectra can be improved in a closed control loop. Instead of using the traditional way of selecting regularization parameters, we observe the coherence change to estimate noise eliminations. Incidentally, the requirement of coherence control can be realized. The errors of the phase are then studied and a phase control algorithm is introduced at the end as a supplement of cross-power spectra control. The Tikhonov filter and the proposed phase control algorithm are tested numerically and experimentally. The results show that the noises in the vicinity of lightly damped resonant peaks are more stubborn. The response spectra are able to be greatly improved by the combination of these two methods.
文摘针对未编码的多输入多输出(MIMO,Multi-Input Multi-Output)系统,提出一种复杂度适中的分组全分集全码率(GFDFR,Group-wise Full Diversity Full Rate)空时编码方案。该方案通过在发送端进行天线分组,各组独立编码,减小全分集全码率(FDFR,Full Diversity FullRate)编码块的大小从而降低系统编解码复杂度;在频率选择性信道中,进一步对子载波分组进行独立编码,获得频率分集(或多径分集),以适中的复杂度在不降低系统分集度的情况下保证了信息的全码率传输,是一种在MIMO信道中极具实用价值的空时编码方案。
基金Sponsored by the National Natural Science Foundation of China(Grant No.61371101)the Shenzhen Biological,Internet,New Energy and New Materials Industry Development Project(Grant No.JC201104210030A)+2 种基金the Science and Technology Basic Research Project of Shenzhen(Grant No.JC200903120174A)the Research Innovation Fund Project of HIT(Grant No.HIT.NSFIR.2010133)the WINDOW-Towards Pervasive Indoor Wireless Networks,and the European Commission under its 7th Framework Program(Grant No.318992)
文摘An extensive 4 x 4 MIMO channel measurement is carried out at 6. 0-6. 4 GHz under a typical classroom environment with channel sounder based on vector network analyzer. Both LOS and NLOS scenarios are considered. The results on path loss, delay spread and spatial correlation are presented. The measurement shows that, for corridor coverage, 2x2 MIMO is more economical than 4x4 MIMO due to high correlation. In order to identify the unique characteristics at the high frequency band, the measured channel parameters at 6. 0-6.4 GHz are compared with those at 2. 45 GHz. The comparison shows that the shortened wavelength of this higher frequency band results in a great difference of channel characteristics. Therefore, our measurement results provide new gnidance for the design and development of the system working on 6. 0-6.4 GHz band.
