- 标题
- 摘要
- 关键词
- 实验方案
- 产品
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[IEEE IGARSS 2018 - 2018 IEEE International Geoscience and Remote Sensing Symposium - Valencia (2018.7.22-2018.7.27)] IGARSS 2018 - 2018 IEEE International Geoscience and Remote Sensing Symposium - Investigations on the Reconstruction of Multistatic Large Along-Track SAR Constellations for HRWS Imaging
摘要： This paper presents first the performance analysis of the state-of-the-art multi-channel SAR signal reconstruction algorithms that suffer from the geometrical approximations. Then, it proposes a two-step signal reconstruction method for spaceborne large along-track baseline multistatic SAR constellations operated with a pulse repetition frequency (PRF) under the Nyquist rate. The suggested algorithm first applies a bulk polychromatic reconstruction in wavenumber domain and then compensates the residual range variance in range-Doppler domain. This simple modification helps to reduce overall phase errors in the reconstruction process of the analysed case with respect to the state-of-the-art algorithms by about one order of magnitude. The performance of the algorithm is verified by showing the results in point target simulations for a multistatic X-band constellation with a resolution of about 15 times the carrier wavelength.
关键词： high-resolution wide-swath (HRWS) radar,multistatic radar signal processing,Digital beamforming
更新于2025-09-23 15:22:29
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Hybrid Beamforming for Millimeter Wave Systems Using the MMSE Criterion
摘要： Hybrid analog and digital beamforming (HBF) has recently emerged as an attractive technique for millimeter-wave (mmWave) communication systems. It well balances the demand for sufficient beamforming gains to overcome the propagation loss and the desire to reduce the hardware cost and power consumption. In this paper, the mean square error (MSE) is chosen as the performance metric to characterize the transmission reliability. Using the minimum sum-MSE criterion, we investigate the HBF design for broadband mmWave transmissions. To overcome the difficulty of solving the multi-variable design problem, the alternating minimization method is adopted to optimize the hybrid transmit and receive beamformers alternatively. Specifically, a manifold optimization based HBF algorithm is firstly proposed, which directly handles the constant modulus constraint of the analog component. Its convergence is then proved. To reduce the computational complexity, we then propose a low-complexity general eigenvalue decomposition based HBF algorithm in the narrowband scenario and three algorithms via the eigenvalue decomposition and orthogonal matching pursuit methods in the broadband scenario. A particular innovation in our proposed alternating minimization algorithms is a carefully designed initialization method, which leads to faster convergence. Furthermore, we extend the sum-MSE based design to that with weighted sum-MSE, which is then connected to the spectral efficiency based design. Simulation results show that the proposed HBF algorithms achieve significant performance improvement over existing ones, and perform close to full-digital beamforming.
关键词： Minimum mean square error (MMSE),Alternating optimization,Manifold optimization (MO),Hybrid analog and digital beamforming (HBF),Millimeter-wave (mmWave) communications
更新于2025-09-23 15:22:29
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[IEEE 2018 China International SAR Symposium (CISS) - Shanghai (2018.10.10-2018.10.12)] 2018 China International SAR Symposium (CISS) - A Novel Algorithm for Spacebome SAR DBF Based on Sparse Spatial Spectrum Estimation
摘要： A novel method of digital beam forming (DBF) based on sparse spatial spectrum estimation for spaceborne synthetic aperture radar (SAR) is proposed in this paper. This method converts the estimation of target scene elevation into the estimation of sparse spatial spectrum, which reduces the impact of the number of signal samples. Finally, the simulated results confirm the validity of the method.
关键词： Sparse Spatial Spectrum Estimation,Synthetic Aperture Radar (SAR),Digital Beamforming (DBF)
更新于2025-09-23 15:22:29
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Decoupling Beam Steering and User Selection for MU-MIMO 60-GHz WLANs
摘要： Multi-user transmission at 60 GHz promises to increase the throughput of next-generation WLANs via both analog and digital beamforming. To maximize the capacity, analog beams need to be jointly configured with user selection and digital weights; however, joint maximization requires prohibitively large training and feedback overhead. In this paper, we scale multi-user 60-GHz WLAN throughput via design of a low-complexity structure for decoupling beam steering and user selection such that analog beam training precedes user selection. We introduce a two-class framework comprising: 1) single-shot selection of users by minimizing overlap of their idealized beam patterns obtained from analog training and 2) interference-aware incremental addition of users via sequential training to better predict inter-user interference. We implement a programmable testbed using software-defined radios and commercial 60-GHz transceivers and conduct over-the-air measurements to collect channel traces for different indoor WLAN deployments. Measurements are conducted using a 12-element phased antenna array as well as horn antennas with different directivity gains to evaluate the performance of practical 60-GHz systems. Using trace-based emulations and high resolution 60-GHz channel models, we show that our decoupling structure experiences less than 5% performance loss compared with maximum achievable rates via joint user-beam selection.
关键词： user selection,MU-MIMO,digital beamforming,60 GHz,IEEE 802.11ay,beam steering
更新于2025-09-23 15:21:21
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[IEEE IGARSS 2018 - 2018 IEEE International Geoscience and Remote Sensing Symposium - Valencia, Spain (2018.7.22-2018.7.27)] IGARSS 2018 - 2018 IEEE International Geoscience and Remote Sensing Symposium - Digital Beamforming Based RFI Mitigation for Synthetic Aperture Radar
摘要： An increasing challenge for P-band Synthetic Aperture Radar (SAR) is Radio Frequency Interference (RFI). RFI results in image distortions and degrades the derived science products. This makes it critical to apply RFI removal techniques to restore the image quality. New advanced techniques can be achieved with Digital Beamforming (DBF) radars such as EcoSAR. In this paper, we present a Range-Dependent Time Minimum Variance Distortionless Response (RDTMVDR) Beamformer and apply it to EcoSAR flight data during post-processing. The antenna pattern (AP) is adaptively changed for each range line which increases the RFI suppression compared to a fixed AP for each pulse. The interferometric image quality is assessed before and after RFI suppression.
关键词： RFI,SAR,Digital Beamforming
更新于2025-09-23 15:21:21
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[IEEE ICASSP 2018 - 2018 IEEE International Conference on Acoustics, Speech and Signal Processing (ICASSP) - Calgary, AB (2018.4.15-2018.4.20)] 2018 IEEE International Conference on Acoustics, Speech and Signal Processing (ICASSP) - Dithered Beamforming for Channel Estimation in Mmwave-Based Massive Mimo
摘要： In this work we consider the challenging problem of channel estimation at the receiver of a massive multiple-input multiple-output system with hybrid analog/digital beamforming and low-resolution quantization. We propose a dithered beamforming architecture, where random control signals are injected to the analog part of the receiver beamformer and to the analog-to-digital converters to introduce randomness into the signal capturing process and combat the stair-case quantization effects. The statistical properties of the dithered output are captured via an Expectation-Maximization approximation of the maximum a-posteriori estimator. A low-complexity algorithm is proposed which exhibits performance close to the oracle-based least-squares estimation of the sparse channel.
关键词： low resolution analog-to-digital converter (ADC),hybrid analog/digital beamforming,millimeter wave (mmWave) massive MIMO
更新于2025-09-23 15:19:57