- 标题
- 摘要
- 关键词
- 实验方案
- 产品
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[IEEE 2019 3rd International Conference on Recent Developments in Control, Automation & Power Engineering (RDCAPE) - NOIDA, India (2019.10.10-2019.10.11)] 2019 3rd International Conference on Recent Developments in Control, Automation & Power Engineering (RDCAPE) - DSP Based Photovoltaic Hardware Development for Controlling Voltage and Current
摘要： We are interested in optimizing transmit beamforming for a visible light communication multiuser system such that the achievable sum rate is maximized. We ?rst derive a closed-form sum rate expression via information-theoretic tools. Then, by further including light-emitting diode optical power constraints, we formulate the rate maximization problem in a mathematical optimization form. To address this dif?cult non-convex problem, we establish an iterative algorithm that exploits sequential parametric convex approximation. Compared with the existing zero-forcing beamforming strategies, the proposed approach does not restrict the co-channel interference to be zero, and thus achieves a higher sum rate, as is validated by simulations.
关键词： achievable rate maximization,Visible light communication (VLC),transmit beamforming
更新于2025-09-16 10:30:52
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Theoretical and Experimental Investigations on a Compact and Broadband TEa??a?? Oversized Deformed Waveguide Bend
摘要： We address a robust beamforming design and power allocation problem for a one-way multi-antenna relay network, where the multi-antenna source implements communication with the multi-antenna destination via a decode-and-forward (DF) relay in the presence of the multiple single-antenna eavesdroppers. The eavesdroppers can only overhear the information flowed from the relay to the destination in the second hop. We aim to maximize the worst-case secrecy rate in the condition that the global channel state information (CSI) is imperfect. To this end, we propose the joint beamforming and power allocation design for the worst-case secrecy rate maximization. However, our proposed design constitutes a non-convex problem, which involves an infinite number of constraints because of the imperfect CSI. To make the problem more tractable, we approximate the problem into several tractable semidefinite programs by semidefinite relaxation, successive convex approximation, and S-procedure techniques, and we propose an iterative algorithm to solve the problem. Furthermore, we show that the proposed algorithm is also applicable for the case the Gaussian wiretap model, where only the eavesdroppers’ CSI is imperfect. Simulation results validate the effectiveness of the proposed algorithm.
关键词： cooperative network,power allocation,robust beamforming,Security
更新于2025-09-16 10:30:52
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[IEEE 2019 7th International Conference on Smart Computing & Communications (ICSCC) - Sarawak, Malaysia, Malaysia (2019.6.28-2019.6.30)] 2019 7th International Conference on Smart Computing & Communications (ICSCC) - On Self Driving Cars: An LED Time of Flight (ToF) based Detection and Ranging using various Unipolar Optical CDMA Codes
摘要： The dramatic surge in the development of autonomous vehicles has generated a need for, among others, improving detection accuracy. Various technologies and techniques have been proposed and adopted for autonomous vehicles, such as computer vision, in conjunction with machine learning and deep learning – neural network. Despite many attempts to improve the accuracy of detection and ranging, the computational load in training the neural network due to the requirement of massive amount of data had increased to a significant extent, along with the cost of operation. Light Detection and Ranging (LiDAR) systems are a new approach to improve the detection and ranging accuracy. However, LED Detection and Ranging (LEDDAR) based systems have not been explored so far. Herein, we present an analysis of the method of detection and ranging using LED and determine its performance for different number of users using Unipolar Optical Code Division Multiple Access (OCDMA) Codes. This was done using probability of error vs. Signal – to – Noise Ratio (SNR) and Distance (in m) using misdetection and false alarm analysis for a given transmitted power of LED obeying the current standards. The method of LED based beamforming by deploying multiple LED’s in an array is proposed to improve the detection and ranging accuracy. Finally, the results show that OCDMA based OOC codes show a low probability of error for a given SNR and Distance and outperformed other OCDMA techniques such as prime codes and hence indicate that OOC codes will be an optimal choice that can be coded in LED’s for the use in self driving cars.
关键词： Computer Vision,Neural Network,Misdetection,Signal – to – Noise Ratio,Beamforming,Probability of Error,False Alarm,Self – Driving Cars,Field – of - View
更新于2025-09-12 10:27:22
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Toward High Accuracy Positioning in 5G via Passive Synchronization of Base Stations Using Thermally-Insensitive Optical Fibers
摘要： Research on millimeter-wave (mmWave) massive multiple-input multiple-output (MIMO) has received much attention. However, due to the propagation characteristic of mmWave, signals will suffer from a significant loss over long range transmission. The mmWave MIMO system may face the challenge of the near-far problem where the user tries to retrieve the information signal (IS) from the base station under the strong intended jamming signal (JS). This paper proposes a novel hybrid beamforming design to cancel the JS that significantly reduces the computational complexity and incurs less feedback signaling overhead. Simulation results demonstrate that our proposed scheme can significantly suppress the interference from the JS and achieve the array gain in the system.
关键词： hybrid beamforming,MIMO,anti-jamming
更新于2025-09-11 14:15:04
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[IEEE 2019 14th IEEE Conference on Industrial Electronics and Applications (ICIEA) - Xi'an, China (2019.6.19-2019.6.21)] 2019 14th IEEE Conference on Industrial Electronics and Applications (ICIEA) - Channel Tracking and Hybrid Energy Beamforming for WPT Enabled IoT System with Mobile mMIMO BS
摘要： In this paper, we consider the channel tracking and energy hybrid beamforming for the wireless power transfer (WPT) enabled Internet of Things (IoT) system, where the mobile base station (MBS) serves a set of half-duplex (HD) sensors that are uniformly distributed within its coverage area. A linear Kalman filter based multipath channel tracking and hybrid energy beamforming scheme is proposed by investigating the temporal and spatial properties of channel. Firstly, the Doppler frequency offset (DFO) is compensated through beam alignment and capturing the precise angular information from signals. Then, the multipath channel is tracked during the angle of arrival time (AOAT). Finally, the hybrid beamforming is applied to realize downlink WPT and uplink data transmission. The superiority of the proposed scheme is evaluated through simulations.
关键词： angle of arrival time (AOAT),mobile base station (MBS),wireless power transfer (WPT),hybrid energy beamforming,Kalman filter,Internet of Things (IoT),Channel tracking,Doppler frequency offset (DFO)
更新于2025-09-11 14:15:04
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[IEEE 2018 IEEE 5G World Forum (5GWF) - Silicon Valley, CA, USA (2018.7.9-2018.7.11)] 2018 IEEE 5G World Forum (5GWF) - Evaluating Power Density for 5G Applications
摘要： The next generation of wireless 5G technology is being continuously designed to meet the growing demand from different industries for more data, more devices, higher speed, and improved operational efficiency. While mmWave bands offer much higher bandwidths, they are subject to higher signal losses when compared to the lower frequency bands currently used for wireless technologies. As such, the industries involved require evolutionary methodologies for the thorough evaluation of 5G mobile devices. The authors offer an advanced near-field measurement technique as a solution for robust assessment of device performance. This novel method introduces the spatial vector evaluation of both electric E and magnetic H fields through the cross-detection of their interaction. Based in terms of the Poynting vector theorem, this two-probe technique provides a steady measurement-based orientation for research within the rapidly changing conditions of the mmWave environment.
关键词： phase shift,beamforming,5G,field patterns,E field,H field,Poynting vector,power density,near-field measurement
更新于2025-09-10 09:29:36
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Adaptive Beamforming with Sensor Position Errors Using Covariance Matrix Construction based on Subspace Bases Transition
摘要： This letter proposes a narrowband interference-plus-noise covariance matrix (INCM) based beamformer, which is robust with sensor position errors for linear array. First, using the subspace fitting and subspace orthogonality techniques, we estimate a set of angle-related bases for the signal-plus-interference subspace (SIS) by solving a joint optimization problem. Second, we obtain the bases transition matrix between the estimated angle-related bases and the orthogonal bases consisting of the dominant eigenvectors of the sample covariance matrix (SCM). The SCM can be expressed as a function of the angle-related bases and the bases transition matrix. We construct the INCM directly from the SIS by eliminating the component of the desired signal from the angle-related bases. Simulations and experimental results show that the proposed beamformer outperforms other tested beamformers in the presence of sensor position errors.
关键词： covariance matrix construction,Bases transition,sensor position error,robust adaptive beamforming
更新于2025-09-10 09:29:36
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Multibeam Digital Array Receiver Using a 16-point Multiplierless DFT Approximation
摘要： An N -element array with receivers subject to an N -point spatial FFT leads to N directionally-orthogonal RF beams. FFTs are fast algorithms for computing an N -point DFT at reduced complexity. The brute-force computation of a DFT requires O(N 2) multiplications while an FFT provides the same computation at O(N log N ) multiplications. The digital chip area and power consumption of the DFT computation are still dominated by the multipliers required by the FFT used. In this paper, an approximation to the 16-point DFT is proposed which maintains mathematical properties close to the ideal 16-point DFT to obtain 16 RF beams by computing an approximate spatial DFT in every clock cycle at significantly lower area and power in the digital realization. The proposed approximation can be implemented using FFT-like fast algorithms that are multiplierless, thereby further reducing the digital chip area and power consumption associated with multiplication in a conventional FFT approach, to zero. A 16-beam beamformer employing a 16-element linear array of patch antennas, direct-conversion receivers and a Xilinx Virtex-6 FPGA based real-time digital back-end clocked at 240 MHz are described as an example realization of 16 complex-valued (IQ) receive-mode RF beams, centered at 2.4 GHz with 120 MHz of bandwidth per beam.
关键词： low-complexity algorithms,spatial DFT,beamforming,Multibeam
更新于2025-09-10 09:29:36
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Space-Time Block Coding Based Beamforming for Beam Squint Compensation
摘要： In this paper, the beam squint problem, which causes significant variations in radiated beam gain over frequencies in millimeter wave communication system, is investigated. A constant modulus beamformer design, which is formulated to maximize the expected average beam gain within the bandwidth with limited variation over frequencies within the bandwidth, is proposed. A semidefinite relaxation (SDR) method is developed to solve the optimization problem under the constant modulus constraints. Depending on the eigenvalues of the optimal solution, either direct beamforming or transmit diversity based beamforming is employed for data transmissions. Through numerical results, the proposed transmission scheme can compensate for beam squint effectively and improve system throughput. Overall, a transmission scheme for beam squint compensation in wideband wireless communication systems is provided.
关键词： Throughput,beam squint,Space-time Block Coding,Beamforming,Millimeter Wave
更新于2025-09-10 09:29:36
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Beamforming Optimization for Time-Modulated Circular-Aperture Grid Array with DE Algorithm
摘要： This paper put forward a method of numerical optimization for the circular-aperture time-modulated grid array. The amplitude weight and time modulation pulse width are optimized based on differential evolution algorithm to get the needed array pattern. Adopting the weighting mode of conventional rectangular array, the equivalent weighting of circular-aperture time-modulated array is decomposed into two independent components respectively in horizontal and vertical direction, so to shorten the length of optimization vector from M×N order to M+N order. Besides, the circular-aperture time-modulated array is symmetrically excited in horizontal and vertical direction. The numerical experiments show that differential evolution algorithm can realize sidelobe level of -35dB and nulling level of -60dB in the patterns of the center frequency and one chosen sideband, and the unexploited sidebands are also suppressed with their peak level lower than -35dB. Meanwhile the dynamic range of the amplitude weighting and time modulation pulse width can be limited in 10dB. The overall efficiency of the time-modulated array is 0.28.
关键词： Beamforming optimization,differential evolution algorithm,circular-aperture grid array,time modulation
更新于2025-09-10 09:29:36