Adaptive digital self-interference cancellation(ADSIC)is a significant method to suppress self-interference and improve the performance of the linear frequency modulated continuous wave(LFMCW)radar.Due to efficient im...Adaptive digital self-interference cancellation(ADSIC)is a significant method to suppress self-interference and improve the performance of the linear frequency modulated continuous wave(LFMCW)radar.Due to efficient implementation structure,the conventional method based on least mean square(LMS)is widely used,but its performance is not sufficient for LFMCW radar.To achieve a better self-interference cancellation(SIC)result and more optimal radar performance,we present an ADSIC method based on fractional order LMS(FOLMS),which utilizes the multi-path cancellation structure and adaptively updates the weight coefficients of the cancellation system.First,we derive the iterative expression of the weight coefficients by using the fractional order derivative and short-term memory principle.Then,to solve the problem that it is difficult to select the parameters of the proposed method due to the non-stationary characteristics of radar transmitted signals,we construct the performance evaluation model of LFMCW radar,and analyze the relationship between the mean square deviation and the parameters of FOLMS.Finally,the theoretical analysis and simulation results show that the proposed method has a better SIC performance than the conventional methods.展开更多
Recent research shows that it is possible to achieve the full-duplex system by cancelling strong self-interference signals, which can be divided into three classes respectively, i.e., passive cancellation, active canc...Recent research shows that it is possible to achieve the full-duplex system by cancelling strong self-interference signals, which can be divided into three classes respectively, i.e., passive cancellation, active cancellation and digital cancellation. This pa- per tries to achieve the full-duplex system without using active cancellation, thus a full-duplex system using a joint mechanism based on a novel passive cancellation method and a novel digital cancellation method is proposed. Therein, a good antenna place- ment guided by the theory of the antenna electromagnetic field for the passive cancellation is presented. For the proposed digital can- cellation method, unlike previous separate mechanisms, it is de- signed by using the recursive least square （RLS） algorithm jointly with passive cancellation. The self-interference channel state in- formation （CSI） is transferred as the input of digital cancellation to balance the performance and the complexity. Experimental results show that the proposed self-interference cancellation mechanism can achieve about 85 dB which is better than the previous re- search. Meanwhile, this design provides a better performance compared with half-duplex with both line-of-sight channel and non- line-of-sight channel.展开更多
For a large-scale adaptive array, the heavy computational load and the high-rate data transmission are two challenges in the implementation of an adaptive digital beamforming system. An efficient parallel digital beam...For a large-scale adaptive array, the heavy computational load and the high-rate data transmission are two challenges in the implementation of an adaptive digital beamforming system. An efficient parallel digital beamforming （DBF） algorithm based on the least mean square algorithm （PLMS） is proposed. An appropriate method is found to partition the least mean square （LMS） algorithm into a number of operational modules, which can be easily executed in a distributed-parallel-processing fashion. As a result, the proposed PLMS algorithm provides an effective solution that can alleviate the bottleneck of high-rate data transmission and reduce the computational cost. PLMS requires less computational load than that of the conventional parallel algorithms based on the recursive least square （RLS） algorithm, as well as it is easier to be implemented to do real time adaptive array processing. Moreover, low sidelobe of the beam pattern is obtained by constraining the static steering vector with Tschebyscheff coefficients. Finally, a scheme of the PLMS algorithm using distributed-parallel-processing system is also proposed. The simulation results demonstrate that the PLMS algorithm has the same interference cancellation performance as that of the conventional LMS algorithm. Moreover, the PLMS algorithm can obtain the same good beamforming performance, regardless how the algorithm is partitioned. It is expected that the proposed algorithm will be used in a large-scale adaptive array system to deal with real time adaptive digital beamforming processing.展开更多
基于生物进化论策略的自适应滤波算法,利用其有性繁殖和无性繁殖的随机搜索能力实现全局最优搜索,可克服最小均方法(Least Mean Square,简称:LMS)对于多峰特性问题有可能收敛于某一局部最小值,无法实现全局最优的缺点。提出峰值系数指标...基于生物进化论策略的自适应滤波算法,利用其有性繁殖和无性繁殖的随机搜索能力实现全局最优搜索,可克服最小均方法(Least Mean Square,简称:LMS)对于多峰特性问题有可能收敛于某一局部最小值,无法实现全局最优的缺点。提出峰值系数指标PR(Peak Ratio)概念解决进化论自适应滤波器的性能评估问题,提出收敛速度CS(Con-verge Speed)指标和峰值系数指标PR高度的方法解决最优滤波参数的选取问题,并对进化论自适应滤波器的降噪进行模拟仿真,讨论了滤波长度和进化系数对进化论自适应算法消噪效果的影响及最优滤波参数。展开更多
文摘Adaptive digital self-interference cancellation(ADSIC)is a significant method to suppress self-interference and improve the performance of the linear frequency modulated continuous wave(LFMCW)radar.Due to efficient implementation structure,the conventional method based on least mean square(LMS)is widely used,but its performance is not sufficient for LFMCW radar.To achieve a better self-interference cancellation(SIC)result and more optimal radar performance,we present an ADSIC method based on fractional order LMS(FOLMS),which utilizes the multi-path cancellation structure and adaptively updates the weight coefficients of the cancellation system.First,we derive the iterative expression of the weight coefficients by using the fractional order derivative and short-term memory principle.Then,to solve the problem that it is difficult to select the parameters of the proposed method due to the non-stationary characteristics of radar transmitted signals,we construct the performance evaluation model of LFMCW radar,and analyze the relationship between the mean square deviation and the parameters of FOLMS.Finally,the theoretical analysis and simulation results show that the proposed method has a better SIC performance than the conventional methods.
基金supported by the National Natural Science Foundation of China(601720456103200661271282)
文摘Recent research shows that it is possible to achieve the full-duplex system by cancelling strong self-interference signals, which can be divided into three classes respectively, i.e., passive cancellation, active cancellation and digital cancellation. This pa- per tries to achieve the full-duplex system without using active cancellation, thus a full-duplex system using a joint mechanism based on a novel passive cancellation method and a novel digital cancellation method is proposed. Therein, a good antenna place- ment guided by the theory of the antenna electromagnetic field for the passive cancellation is presented. For the proposed digital can- cellation method, unlike previous separate mechanisms, it is de- signed by using the recursive least square （RLS） algorithm jointly with passive cancellation. The self-interference channel state in- formation （CSI） is transferred as the input of digital cancellation to balance the performance and the complexity. Experimental results show that the proposed self-interference cancellation mechanism can achieve about 85 dB which is better than the previous re- search. Meanwhile, this design provides a better performance compared with half-duplex with both line-of-sight channel and non- line-of-sight channel.
文摘For a large-scale adaptive array, the heavy computational load and the high-rate data transmission are two challenges in the implementation of an adaptive digital beamforming system. An efficient parallel digital beamforming （DBF） algorithm based on the least mean square algorithm （PLMS） is proposed. An appropriate method is found to partition the least mean square （LMS） algorithm into a number of operational modules, which can be easily executed in a distributed-parallel-processing fashion. As a result, the proposed PLMS algorithm provides an effective solution that can alleviate the bottleneck of high-rate data transmission and reduce the computational cost. PLMS requires less computational load than that of the conventional parallel algorithms based on the recursive least square （RLS） algorithm, as well as it is easier to be implemented to do real time adaptive array processing. Moreover, low sidelobe of the beam pattern is obtained by constraining the static steering vector with Tschebyscheff coefficients. Finally, a scheme of the PLMS algorithm using distributed-parallel-processing system is also proposed. The simulation results demonstrate that the PLMS algorithm has the same interference cancellation performance as that of the conventional LMS algorithm. Moreover, the PLMS algorithm can obtain the same good beamforming performance, regardless how the algorithm is partitioned. It is expected that the proposed algorithm will be used in a large-scale adaptive array system to deal with real time adaptive digital beamforming processing.
文摘基于生物进化论策略的自适应滤波算法,利用其有性繁殖和无性繁殖的随机搜索能力实现全局最优搜索,可克服最小均方法(Least Mean Square,简称:LMS)对于多峰特性问题有可能收敛于某一局部最小值,无法实现全局最优的缺点。提出峰值系数指标PR(Peak Ratio)概念解决进化论自适应滤波器的性能评估问题,提出收敛速度CS(Con-verge Speed)指标和峰值系数指标PR高度的方法解决最优滤波参数的选取问题,并对进化论自适应滤波器的降噪进行模拟仿真,讨论了滤波长度和进化系数对进化论自适应算法消噪效果的影响及最优滤波参数。
