In array signal processing, 2-D spatial-spectrum estimation is required to determine DOA of multiple signals. The circular array of sensors is found to possess several nice properties for DOA estimation of wide-band s...In array signal processing, 2-D spatial-spectrum estimation is required to determine DOA of multiple signals. The circular array of sensors is found to possess several nice properties for DOA estimation of wide-band sources. C. U. Padmini, et al.(1994) had suggested that the frequency-direction ambiguity in azimuth estimation of wide-baud signals received by a uniform linear array (ULA) can be avoided by using a circular array, even without the use of any delay elements. In 2-D spatial-spectrum estimation for wide-band signals, the authors find that it is impossible to avoid the ambiguity in source frequency-elevation angle pairs using a circular array. In this paper, interpolated circular arrays are used to perform 2-D spatial-spectrum estimation for wide-band sources. In the estimation, a large aperture circular array (Υ】λmin/2) is found to possess superior resolution capability and robustness.展开更多
针对太赫兹频段高速移动场景,提出了一种参考信号方案——增强型离散傅里叶变换扩展正交频分复用(E DFT-s-OFDM)DMRS:将具有循环前缀(CP)和循环后缀(CS)的参考信号序列分割为首部和尾部参考信号序列,然后分别嵌入每个OFDM符号的尾部和...针对太赫兹频段高速移动场景,提出了一种参考信号方案——增强型离散傅里叶变换扩展正交频分复用(E DFT-s-OFDM)DMRS:将具有循环前缀(CP)和循环后缀(CS)的参考信号序列分割为首部和尾部参考信号序列,然后分别嵌入每个OFDM符号的尾部和首部。这种方案的优点在于,前一个OFDM符号的尾部和后一个OFDM符号的首部构成一个完整的参考信号序列,从而允许接收端在每个OFDM符号间隔内都能进行信道估计,提高了信道估计的精度和实时性。此外,相邻OFDM符号的首部和尾部参考信号序列相同,从而省去了每个OFDM符号的传统循环前缀(CP),提高了频谱效率。仿真结果表明,在太赫兹频段高速移动场景下,与5G NR DFT-s-OFDM波形的DMRS方案相比,该方案的信道估计更精确,通信系统的频谱效率更高。展开更多
Multi-channel sampling for band-limited signals is fundamental in the theory of multi-channel parallel A/D environment and multiplexing wireless communication environment. As the fractional Fourier transform has been ...Multi-channel sampling for band-limited signals is fundamental in the theory of multi-channel parallel A/D environment and multiplexing wireless communication environment. As the fractional Fourier transform has been found wide applications in signal processing fields, it is necessary to consider the multi-channel sampling theorem based on the fractional Fourier transform. In this paper, the multi-channel sampling theorem for the fractional band-limited signal is firstly proposed, which is the generalization of the well-known sampling theorem for the fractional Fourier transform. Since the periodic nonuniformly sampled signal in the fractional Fourier domain has valuable applications, the reconstruction expression for the periodic nonuniformly sampled signal has been then obtained by using the derived multi-channel sampling theorem and the specific space-shifting and phase-shifting properties of the fractional Fourier transform. Moreover, by designing different fractional Fourier filters, we can obtain reconstruction methods for other sampling strategies.展开更多
We propose a low complexity iterative algorithm for band limited signal extrapolation. The extrapolation method is based on the decomposition of finite segments of the signal via truncated series of real-valued linear...We propose a low complexity iterative algorithm for band limited signal extrapolation. The extrapolation method is based on the decomposition of finite segments of the signal via truncated series of real-valued linear prolate functions. Our theoretical derivation shows that given a truncated series (up to a selectable value) of prolate functions, it is possible to extrapolate the band limited function elsewhere if each extrapolated portion of the function is subject only to moderate truncation errors that we quantify in this paper. The effects of different sources of errors have been analyzed via extensive simulations. We have investigated a property of the signal decomposition formula based on linear prolate functions whereby the integration interval does not need to be symmetric with respect to the origin while time-shifted prolate functions are used in the series.展开更多
In array signal processing,the existing methods for DOA estimation of wide-band signals are only related to the azimuth estimation when the number or sensors is known.It is shown that a circular array possesses severa...In array signal processing,the existing methods for DOA estimation of wide-band signals are only related to the azimuth estimation when the number or sensors is known.It is shown that a circular array possesses several nice properties.2-D spatial-spectrum estimation for wide-band sources is performed by using a circular array of sensors with sample delay lines.Further,the Choi' s approach is extended,which was suggested to estimate DOA of narrow-band signals when the number of sensor was unknown,to wide-band signal processing.The extended approach is shown to be quite adequate for wide-band signal subspace spatial-spectrum estimation (BASS-LE),and a large aperture (r>λvin/2) circular array is found to possess superior resolution capability and robustness.展开更多
文摘In array signal processing, 2-D spatial-spectrum estimation is required to determine DOA of multiple signals. The circular array of sensors is found to possess several nice properties for DOA estimation of wide-band sources. C. U. Padmini, et al.(1994) had suggested that the frequency-direction ambiguity in azimuth estimation of wide-baud signals received by a uniform linear array (ULA) can be avoided by using a circular array, even without the use of any delay elements. In 2-D spatial-spectrum estimation for wide-band signals, the authors find that it is impossible to avoid the ambiguity in source frequency-elevation angle pairs using a circular array. In this paper, interpolated circular arrays are used to perform 2-D spatial-spectrum estimation for wide-band sources. In the estimation, a large aperture circular array (Υ】λmin/2) is found to possess superior resolution capability and robustness.
文摘针对太赫兹频段高速移动场景,提出了一种参考信号方案——增强型离散傅里叶变换扩展正交频分复用(E DFT-s-OFDM)DMRS:将具有循环前缀(CP)和循环后缀(CS)的参考信号序列分割为首部和尾部参考信号序列,然后分别嵌入每个OFDM符号的尾部和首部。这种方案的优点在于,前一个OFDM符号的尾部和后一个OFDM符号的首部构成一个完整的参考信号序列,从而允许接收端在每个OFDM符号间隔内都能进行信道估计,提高了信道估计的精度和实时性。此外,相邻OFDM符号的首部和尾部参考信号序列相同,从而省去了每个OFDM符号的传统循环前缀(CP),提高了频谱效率。仿真结果表明,在太赫兹频段高速移动场景下,与5G NR DFT-s-OFDM波形的DMRS方案相比,该方案的信道估计更精确,通信系统的频谱效率更高。
基金Supported partially by the National Natural Science Foundation of China (Grant Nos. 60232010 and 60572094) the National Natural Science Foundation of China for Distinguished Young Scholars (Grant No. 60625104)
文摘Multi-channel sampling for band-limited signals is fundamental in the theory of multi-channel parallel A/D environment and multiplexing wireless communication environment. As the fractional Fourier transform has been found wide applications in signal processing fields, it is necessary to consider the multi-channel sampling theorem based on the fractional Fourier transform. In this paper, the multi-channel sampling theorem for the fractional band-limited signal is firstly proposed, which is the generalization of the well-known sampling theorem for the fractional Fourier transform. Since the periodic nonuniformly sampled signal in the fractional Fourier domain has valuable applications, the reconstruction expression for the periodic nonuniformly sampled signal has been then obtained by using the derived multi-channel sampling theorem and the specific space-shifting and phase-shifting properties of the fractional Fourier transform. Moreover, by designing different fractional Fourier filters, we can obtain reconstruction methods for other sampling strategies.
文摘We propose a low complexity iterative algorithm for band limited signal extrapolation. The extrapolation method is based on the decomposition of finite segments of the signal via truncated series of real-valued linear prolate functions. Our theoretical derivation shows that given a truncated series (up to a selectable value) of prolate functions, it is possible to extrapolate the band limited function elsewhere if each extrapolated portion of the function is subject only to moderate truncation errors that we quantify in this paper. The effects of different sources of errors have been analyzed via extensive simulations. We have investigated a property of the signal decomposition formula based on linear prolate functions whereby the integration interval does not need to be symmetric with respect to the origin while time-shifted prolate functions are used in the series.
文摘In array signal processing,the existing methods for DOA estimation of wide-band signals are only related to the azimuth estimation when the number or sensors is known.It is shown that a circular array possesses several nice properties.2-D spatial-spectrum estimation for wide-band sources is performed by using a circular array of sensors with sample delay lines.Further,the Choi' s approach is extended,which was suggested to estimate DOA of narrow-band signals when the number of sensor was unknown,to wide-band signal processing.The extended approach is shown to be quite adequate for wide-band signal subspace spatial-spectrum estimation (BASS-LE),and a large aperture (r>λvin/2) circular array is found to possess superior resolution capability and robustness.
