Beamspace super-resolution methods for elevation estimation in multipath environment has attracted significant attention, especially the beamspace maximum likelihood(BML)algorithm. However, the difference beam is rare...Beamspace super-resolution methods for elevation estimation in multipath environment has attracted significant attention, especially the beamspace maximum likelihood(BML)algorithm. However, the difference beam is rarely used in superresolution methods, especially in low elevation estimation. The target airspace information in the difference beam is different from the target airspace information in the sum beam. And the use of difference beams does not significantly increase the complexity of the system and algorithms. Thus, this paper applies the difference beam to the beamformer to improve the elevation estimation performance of BML algorithm. And the direction and number of beams can be adjusted according to the actual needs. The theoretical target elevation angle root means square error(RMSE) and the computational complexity of the proposed algorithms are analyzed. Finally, computer simulations and real data processing results demonstrate the effectiveness of the proposed algorithms.展开更多
Because of the range-angle dependency in random log frequency diverse array(RD-log-FDA) radar, a method for designing beamspace transformation matrix in angle and range based on the receive signal has been proposed.It...Because of the range-angle dependency in random log frequency diverse array(RD-log-FDA) radar, a method for designing beamspace transformation matrix in angle and range based on the receive signal has been proposed.It is demonstrated that the designed beamspace transformation matrix basically meets the requirements of beam gain.However, there are some problems in the transformation matrix designed, such as unstable beam gain and high sidelobe.Hence, we propose an optimization method by adjusting array element spacing and random number in frequency offset to get the optimum beam gain.Therefore, particle swarm optimization(PSO) is used to find the optimal solution.The beam gain comparison before and after the optimization is obtained by simulation, and the results show that the optimized array after beamspace preprocessing has more stable beam gain, lower sidelobe, and higher resolution in parameter estimation.In conclusion, the RD-log-FDA is capable of forming desired beam gain in angle and distance through beamspace preprocessing, and suppressing interference signals in other areas.展开更多
Millimeter-wave communications are suitable for application to massive multiple-input multiple-output systems in order to satisfy the ever-growing data traffic demands of the next-generation wireless communication.How...Millimeter-wave communications are suitable for application to massive multiple-input multiple-output systems in order to satisfy the ever-growing data traffic demands of the next-generation wireless communication.However,their practical deployment is hindered by the high cost of complex hardware,such as radio frequency(RF)chains.To this end,operation in the beamspace domain,through beam selection,is a viable solution.Generally,the conventional beam selection schemes focus on the feedback and exhaustive search techniques.In addition,since the same beam in the beamspace may be assigned to a different user,conventional beam selection schemes suffer serious multi-user interference.In addition,some RF chains may be wasted,since they do not contribute to the sum-rate performance.Thus,a fingerprint-based beam selection scheme is proposed to solve these problems.The proposed scheme conducts offline group-based fingerprint database construction and online beam selection to mitigate multi-user interference.In the offline phase,the contributing users with the same best beam are grouped.After grouping,a fingerprint database is created for each group.In the online phase,beam selection is performed for purposes of interference mitigation using the information contained in the group-based fingerprint database.The simulation results confirm that the proposed beam selection scheme can achieve a signal-to-interference-plus-noise ratio and sum-rate performance which is close to those of a fully digital system,and having much higher energy efficiency.展开更多
A low-complexity angle estimation method for multiple-input multiple-output(MIMO) radar using beamspace unitary estimation of signal parameters via rotational invariance techniques(ESPRIT) is presented.Reduced-dimensi...A low-complexity angle estimation method for multiple-input multiple-output(MIMO) radar using beamspace unitary estimation of signal parameters via rotational invariance techniques(ESPRIT) is presented.Reduced-dimensional transformation is firstly utilized as a pre-processing to obtain the reduced-dimensional data matrix, and then a conjugate centrosymmetric discrete Fourier transform(DFT) matrix is employed to map the received data into lower-dimensional beamspace and transforms the complex covariance matrix into a realvalued one. At last, the rotational invariance structure of the real-valued signal subspace is constructed in the beamspace to obtain the estimation of direction of arrival(DOA). Compared with the other ESPRIT algorithms,the proposed method can achieve improved estimation performance with a significantly reduced computational complexity. Simulation results are presented to demonstrate the effectiveness of the proposed method.展开更多
This paper discusses the problem of low-elevation target height estimation for multiple-input multiple-output(MIMO)radar in multipath environments.The beamspace compresses the data and is ideal for reducing the comput...This paper discusses the problem of low-elevation target height estimation for multiple-input multiple-output(MIMO)radar in multipath environments.The beamspace compresses the data and is ideal for reducing the computational burden of elevation estimation.To obtain the height parameter of the target accurately,we propose a height estimation method based on a beamspace joint alternating iterative(BJAI)algorithm in MIMO radar.This method mainly converts the reduced-dimensional MIMO radar element space data into beamspace data and whitens them to improve the reliability.Then,a simplified model is used to obtain the initial value of the elevation,and we combine the reflection coefficient and the target elevation angle for alternate estimation.Finally,we calculate the target height using the obtained elevation information.Simulation results verify that the proposed algorithm has high estimation accuracy and strong robustness.展开更多
基金supported by the Fund for Foreign Scholars in University Research and Teaching Programs (B18039)。
文摘Beamspace super-resolution methods for elevation estimation in multipath environment has attracted significant attention, especially the beamspace maximum likelihood(BML)algorithm. However, the difference beam is rarely used in superresolution methods, especially in low elevation estimation. The target airspace information in the difference beam is different from the target airspace information in the sum beam. And the use of difference beams does not significantly increase the complexity of the system and algorithms. Thus, this paper applies the difference beam to the beamformer to improve the elevation estimation performance of BML algorithm. And the direction and number of beams can be adjusted according to the actual needs. The theoretical target elevation angle root means square error(RMSE) and the computational complexity of the proposed algorithms are analyzed. Finally, computer simulations and real data processing results demonstrate the effectiveness of the proposed algorithms.
基金supported by the National Natural Science Foundation of China (62001506)。
文摘Because of the range-angle dependency in random log frequency diverse array(RD-log-FDA) radar, a method for designing beamspace transformation matrix in angle and range based on the receive signal has been proposed.It is demonstrated that the designed beamspace transformation matrix basically meets the requirements of beam gain.However, there are some problems in the transformation matrix designed, such as unstable beam gain and high sidelobe.Hence, we propose an optimization method by adjusting array element spacing and random number in frequency offset to get the optimum beam gain.Therefore, particle swarm optimization(PSO) is used to find the optimal solution.The beam gain comparison before and after the optimization is obtained by simulation, and the results show that the optimized array after beamspace preprocessing has more stable beam gain, lower sidelobe, and higher resolution in parameter estimation.In conclusion, the RD-log-FDA is capable of forming desired beam gain in angle and distance through beamspace preprocessing, and suppressing interference signals in other areas.
基金The Ministry of Science and ICT(MSIT),Korea,under the Information Technology Research Center(ITRC)support program(IITP-2020-2016-0-00314)supervised by the Institute for Information&communications Technology Planning&Evaluation(IITP)was supported by the National Research Foundation of Korea(NRF)grant funded by the Korea government(MSIT:Ministry of Science and ICT)(2018R1A2B6002255 and 2020R1I1A1A01073948).
文摘Millimeter-wave communications are suitable for application to massive multiple-input multiple-output systems in order to satisfy the ever-growing data traffic demands of the next-generation wireless communication.However,their practical deployment is hindered by the high cost of complex hardware,such as radio frequency(RF)chains.To this end,operation in the beamspace domain,through beam selection,is a viable solution.Generally,the conventional beam selection schemes focus on the feedback and exhaustive search techniques.In addition,since the same beam in the beamspace may be assigned to a different user,conventional beam selection schemes suffer serious multi-user interference.In addition,some RF chains may be wasted,since they do not contribute to the sum-rate performance.Thus,a fingerprint-based beam selection scheme is proposed to solve these problems.The proposed scheme conducts offline group-based fingerprint database construction and online beam selection to mitigate multi-user interference.In the offline phase,the contributing users with the same best beam are grouped.After grouping,a fingerprint database is created for each group.In the online phase,beam selection is performed for purposes of interference mitigation using the information contained in the group-based fingerprint database.The simulation results confirm that the proposed beam selection scheme can achieve a signal-to-interference-plus-noise ratio and sum-rate performance which is close to those of a fully digital system,and having much higher energy efficiency.
基金the National Natural Science Foundation of China(No.61602377)
文摘A low-complexity angle estimation method for multiple-input multiple-output(MIMO) radar using beamspace unitary estimation of signal parameters via rotational invariance techniques(ESPRIT) is presented.Reduced-dimensional transformation is firstly utilized as a pre-processing to obtain the reduced-dimensional data matrix, and then a conjugate centrosymmetric discrete Fourier transform(DFT) matrix is employed to map the received data into lower-dimensional beamspace and transforms the complex covariance matrix into a realvalued one. At last, the rotational invariance structure of the real-valued signal subspace is constructed in the beamspace to obtain the estimation of direction of arrival(DOA). Compared with the other ESPRIT algorithms,the proposed method can achieve improved estimation performance with a significantly reduced computational complexity. Simulation results are presented to demonstrate the effectiveness of the proposed method.
基金Project supported by the National Natural Science Foundation of China(No.62271379)the National Radar Signal Processing Laboratory(No.KGJ202401)the Fundamental Research Funds for the Central Universities and the Innovation Fund of Xidian University(No.YJSJ24011)。
文摘This paper discusses the problem of low-elevation target height estimation for multiple-input multiple-output(MIMO)radar in multipath environments.The beamspace compresses the data and is ideal for reducing the computational burden of elevation estimation.To obtain the height parameter of the target accurately,we propose a height estimation method based on a beamspace joint alternating iterative(BJAI)algorithm in MIMO radar.This method mainly converts the reduced-dimensional MIMO radar element space data into beamspace data and whitens them to improve the reliability.Then,a simplified model is used to obtain the initial value of the elevation,and we combine the reflection coefficient and the target elevation angle for alternate estimation.Finally,we calculate the target height using the obtained elevation information.Simulation results verify that the proposed algorithm has high estimation accuracy and strong robustness.
