本文研究了基于1-比特模数转换器(Analog to Digital Converters,ADCs)的大规模多输入多输出(Multiple Input Multiple Output,MIMO)系统上行链路的多用户频率同步问题,其中多个单天线用户与配置大规模天线阵列的基站采用正交频分复用(O...本文研究了基于1-比特模数转换器(Analog to Digital Converters,ADCs)的大规模多输入多输出(Multiple Input Multiple Output,MIMO)系统上行链路的多用户频率同步问题,其中多个单天线用户与配置大规模天线阵列的基站采用正交频分复用(Orthogonal Frequency Division Multiplexing,OFDM)技术进行通信.针对多用户角度不重叠的场景,本文利用接收波束成形网络进行多用户干扰消除,从混叠的多用户信号中提取出目标用户的信息,进而对载波频偏(Carrier Frequency Offset,CFO)进行估计.其次,考虑1-比特ADC导致的量化噪声对系统性能的影响,理论推导了基站接收端处的信噪比(Signal-Noise Ratio,SNR).为了提升系统的性能,基于理论SNR对波束成形网络进行了优化设计.最后,计算机仿真结果显示了所提出的频偏估计算法与其他现有算法相比具有更好的性能.展开更多
1-bit采样因其低成本、低功耗等优势引起了广泛关注,本文主要讨论1-bit采样下雷达的脉压性能。首先,推导了1-bit采样造成的信噪比损失,分析了1-bit采样的适用条件,进而发现1-bit采样适合于单次回波信噪比较低的应用场景。接着,通过理论...1-bit采样因其低成本、低功耗等优势引起了广泛关注,本文主要讨论1-bit采样下雷达的脉压性能。首先,推导了1-bit采样造成的信噪比损失,分析了1-bit采样的适用条件,进而发现1-bit采样适合于单次回波信噪比较低的应用场景。接着,通过理论分析可知相对于高精度脉压系数,1-bit脉压系数会带来额外的脉压信噪比损失,但实现方式更为简单。此外,分析了在高信噪比下,发射信号为线性调频(linear frequency modulation,LFM)信号时周期性假目标出现的原因,并且指出相位编码可有效避免假目标出现。仿真实验验证了以上理论推导的正确性。最后,结合某高频(high frequency,HF)地波雷达的实测数据验证了1-bit采样的可行性。展开更多
This paper proposes a method to improve the spu-rious-free dynamic ranges(SFDRs)of 1-bit sampled signals greatly,which is very beneficial to multi-tone signals detection.Firstly,the relationship between the fundamenta...This paper proposes a method to improve the spu-rious-free dynamic ranges(SFDRs)of 1-bit sampled signals greatly,which is very beneficial to multi-tone signals detection.Firstly,the relationship between the fundamental component and the third harmonic component of 1-bit sampled signals is analyzed for determining four contiguous special frequency bands,which do not contain any third harmonics inside and co-ver 77.8%of the whole Nyquist sampling frequency band.Then,we present a special 4-channel monobit receiver model,where appropriate filter banks are used to obtain four desired pass bands before 1-bit quantization and each channel can sample and process sampled data independently to achieve a good in-stantaneous dynamic range without sacrificing the real-time per-formance or computing resources.The simulation results show that the proposed method effectively eliminates the effect of the most harmonics on SFDRs and the mean SFDR is increased to to 20 dB.Besides,the multi-signals simulation results indicate that the maximum amplitude separation(dynamic range)of two signals in each channel is 12 dB while the proposed monobit re-ceiver can deal with up to eight simultaneous arrival signals.In general,the designing method proposed in this paper has a po-tential engineering value.展开更多
One-bit quantization is a promising technique due to its performance retention and complexity reduction in a deceptive jammer against synthetic aperture radar(SAR).In this paper,the 1-bit quantization technology is ut...One-bit quantization is a promising technique due to its performance retention and complexity reduction in a deceptive jammer against synthetic aperture radar(SAR).In this paper,the 1-bit quantization technology is utilized to agilely generate split false targets in the SAR imagery once the radar signal is intercepted,which reduces the complexity of the jammer significantly with guaranteed focusing quality.A single-frequency threshold is used to decompose harmonics incurred by the 1-bit quantization,and its parameters are adjusted through different pulse repetition intervals to provide steerable modulations.In this way,the SAR signal is split into coupled false scatterers during the 1-bit interception.By further deploying amplitude,time-delay,and Doppler frequency modulations on the 1-bit intercepted signal,the split false targets are created.The proposed approach is compared with different deceptive jamming methods to show its validity in effectiveness and cost,and numerical experiments are also presented for verification.展开更多
文摘本文研究了基于1-比特模数转换器(Analog to Digital Converters,ADCs)的大规模多输入多输出(Multiple Input Multiple Output,MIMO)系统上行链路的多用户频率同步问题,其中多个单天线用户与配置大规模天线阵列的基站采用正交频分复用(Orthogonal Frequency Division Multiplexing,OFDM)技术进行通信.针对多用户角度不重叠的场景,本文利用接收波束成形网络进行多用户干扰消除,从混叠的多用户信号中提取出目标用户的信息,进而对载波频偏(Carrier Frequency Offset,CFO)进行估计.其次,考虑1-比特ADC导致的量化噪声对系统性能的影响,理论推导了基站接收端处的信噪比(Signal-Noise Ratio,SNR).为了提升系统的性能,基于理论SNR对波束成形网络进行了优化设计.最后,计算机仿真结果显示了所提出的频偏估计算法与其他现有算法相比具有更好的性能.
文摘1-bit采样因其低成本、低功耗等优势引起了广泛关注,本文主要讨论1-bit采样下雷达的脉压性能。首先,推导了1-bit采样造成的信噪比损失,分析了1-bit采样的适用条件,进而发现1-bit采样适合于单次回波信噪比较低的应用场景。接着,通过理论分析可知相对于高精度脉压系数,1-bit脉压系数会带来额外的脉压信噪比损失,但实现方式更为简单。此外,分析了在高信噪比下,发射信号为线性调频(linear frequency modulation,LFM)信号时周期性假目标出现的原因,并且指出相位编码可有效避免假目标出现。仿真实验验证了以上理论推导的正确性。最后,结合某高频(high frequency,HF)地波雷达的实测数据验证了1-bit采样的可行性。
文摘This paper proposes a method to improve the spu-rious-free dynamic ranges(SFDRs)of 1-bit sampled signals greatly,which is very beneficial to multi-tone signals detection.Firstly,the relationship between the fundamental component and the third harmonic component of 1-bit sampled signals is analyzed for determining four contiguous special frequency bands,which do not contain any third harmonics inside and co-ver 77.8%of the whole Nyquist sampling frequency band.Then,we present a special 4-channel monobit receiver model,where appropriate filter banks are used to obtain four desired pass bands before 1-bit quantization and each channel can sample and process sampled data independently to achieve a good in-stantaneous dynamic range without sacrificing the real-time per-formance or computing resources.The simulation results show that the proposed method effectively eliminates the effect of the most harmonics on SFDRs and the mean SFDR is increased to to 20 dB.Besides,the multi-signals simulation results indicate that the maximum amplitude separation(dynamic range)of two signals in each channel is 12 dB while the proposed monobit re-ceiver can deal with up to eight simultaneous arrival signals.In general,the designing method proposed in this paper has a po-tential engineering value.
基金National Natural Science Foundation of China(Grant No.61801297,62171293,U1713217,61971218,61601304,61801302,61701528)Natural Science Funding of Guangdong Province(Grant No.2017A030313336)+1 种基金Foundation of Shenzhen City(Grant No.JCYJ20170302142545828)Shenzhen University(Grant No.2019119,2016057)to provide fund for conducting experiments。
文摘One-bit quantization is a promising technique due to its performance retention and complexity reduction in a deceptive jammer against synthetic aperture radar(SAR).In this paper,the 1-bit quantization technology is utilized to agilely generate split false targets in the SAR imagery once the radar signal is intercepted,which reduces the complexity of the jammer significantly with guaranteed focusing quality.A single-frequency threshold is used to decompose harmonics incurred by the 1-bit quantization,and its parameters are adjusted through different pulse repetition intervals to provide steerable modulations.In this way,the SAR signal is split into coupled false scatterers during the 1-bit interception.By further deploying amplitude,time-delay,and Doppler frequency modulations on the 1-bit intercepted signal,the split false targets are created.The proposed approach is compared with different deceptive jamming methods to show its validity in effectiveness and cost,and numerical experiments are also presented for verification.
