Beamforming Research Articles

Comparative Study of the Behavior and Strength of Laterally Supported Steel Beams with Laterally Unsupported Steel Beams

A laterally supported beam is a beam that is supported along its length to prevent lateral buckling. Lateral support can be provided by bracing, sheathing, or other means to prevent the beam form deflecting laterally. This type of support is important in preventing the beam from failing under the influence of lateral loads, such as wind or seismic forces. In contrast, a laterally unrestrained beam is a beam that is not restraint(transversely) along its length which its top flange will be subjected to lateral torsional buckling. To prevent this type of buckling, both flanges of the section or at least its top flange must have lateral support. In a beam, if the flange or its compression region is sufficiently prevented from displacement and twisting, or when the compression flange is directly connected to the roof, the beam is considered braced at the same point. This paper aims to investigate the comparison of behavior and strength between fully laterally supported and laterally unsupported beams in steel structures. To carry out this study, extensive parametric analysis is performed by considering different sizes of beams, spacing of the lateral supports and comparing the strength of laterally supported beam compared with laterally unsupported beam by practical examples. The findings shows that if the steel beams have full lateral support, the plastic hinge is created at the point with the maximum moment and the strength of that beams is not limited by lateral torsional buckling. on the contrary, if the same steel beam does not have lateral support or the unbraced length of compression flange are very large, its strength is limited by lateral torsional buckling, and its strength is more than 15 % lower than if it has a continues lateral support.

Digital Beamforming and Receiving Array Research Based on Rydberg Field Probes

Digital Beamforming and Receiving Array Research Based on Rydberg Field Probes

LSTM-Aided Selective Beam Tracking in Multi-Cell Scenario for mmWave Wireless Systems

Millimeter wave systems rely on narrow beams (beamforming) and dense cell deployments for reliable communication. Tracking these beams from multiple cells can increase power consumption and signaling overhead. Therefore, a mobile needs to selectively and smartly track beams under power/overhead constraints. In this paper, we propose a fully data-driven, long short-term memory (LSTM)-based, selective link tracking approach. These approaches are developed for both fixed and adaptive power/overhead constraints, which also predict the magnitude of the best performing beam. The algorithms are validated in simulations of a 28GHz 5G New Radio (NR)-like system in an urban area with realistic navigation routes utilizing detailed ray-tracing. The simulations demonstrate that the proposed methods outperform classic and deep reinforcement learning (RL) approaches in terms of tracking accuracy, power saving and overhead for both analog and digital beamforming architectures. We also argue that the prediction of the proposed method can be easily performed on a digital signal processor of a modern chipset with minimal resource consumption.

Transversely heterogeneous nonlocal Timoshenko beam theory: A reduced-order modeling via distributed-order fractional operators

Nonlocal effects are widely identified in micro/nano systems and have been studied extensively in recent decades. Nevertheless, existing studies mostly focus on the modeling of homogeneous nonlocal systems and as a result, cannot model micro/nanostructures with heterogeneously distributed nonlocal effects. This study introduces a reduced-order nonlocal Timoshenko beam model that facilitates precise modeling of micro-elastic beams with layer-wise heterogeneous nonlocal effects. First, a fully-resolved two-dimensional (2D) plane-strain fractional-order nonlocal elastic framework is developed to provide reference solutions for 2D nonlocal beam problems. Building upon this general nonlocal elasticity theory, an equivalent one-dimensional (1D) nonlocal Timoshenko model is then developed. The layer-wise heterogeneous nonlocal information is captured by using distributed-order (DO) operators, and the impacts arising from the nonlocal heterogeneity are further characterized by introducing two auxiliary parameters. Both 1D and 2D approaches are applied to simulate the mechanical responses of nonlocal beams. Direct comparisons of numerical simulations produced by either the 1D or the fully-resolved 2D model confirm that the DO Timoshenko beam formulation (together with the two auxiliary parameters) can capture not only the overall beam deflection but also the additional shear effect induced by the heterogeneous nonlocality. Computational cost assessment also indicates the proposed approach’s superior performance. The proposed DO Timoshenko model enables model-order reduction without compromising the heterogeneous nonlocal description of the material hence leading to an efficient and accurate reduced-order nonlocal modeling approach that addresses the limitations of prior nonlocal microstructural theories and extends applicability to a broader range of heterogeneous nano/microstructures.

Digital Beamforming Features in Subaperture Antenna Arrays of Highly Informative Space Radars with Aperture Synthesis

It is shown that during digital beamforming in a subaperture antenna array of highly informative space radars with synthetic aperture, it is necessary to provide a procedure for equalizing the time delays of the subaperture output signals for transmission and reception. It has been established that losses in the signal-to-noise ratio on a radar image of a point target for a typical aperture size at an elevation angle of 0.7 m and a signal spectrum width of 600 MHz reach 2.1 and 7.5 dB for off-nadir angles of 21° and 50°, respectively. Recommendations are formulated for equalizing time delays for transmission and reception based on spectral processing. Simulation results are presented.

Optimal direction of arrival estimation for digital beamforming using machine learning

Optimal direction of arrival estimation for digital beamforming using machine learning

Energy Efficient Resource Allocation for Uplink RIS-Aided Millimeter-Wave Networks With NOMA

In this paper, energy efficiency (EE) is maximized for the reconfigurable intelligent surface (RIS) aided millimeter-Wave (mmWave) networks with non-orthogonal multiple access (NOMA) and multiple mobile devices. To this end, we first propose the EE optimization, under the constraints of maximum power, minimal rate of devices and constant modulus of beamforming (BF) vectors. Then, the joint resource allocation scheme of power allocation (PA) and BF is designed. Specifically, given PA, an effective iterative algorithm based on the majorizationminimization, concave-convex procedure and block coordinate descent (BCD) is presented to obtain closed-form solutions of suboptimal passive BF (PBF) and analog BF (ABF) for each iteration. Then, given PBF and ABF, an effective iterative algorithm based on the successive convex approximation, BCD and Dinkelbach methods is derived to achieve suboptimal closedform PA for each iteration. By incorporating these two algorithms into the BCD method, a joint optimization algorithm for EE maximization is presented. As a result, joint resource allocation of PA, PBF and ABF is attained. Besides, the convergence and complexity of the algorithms are analyzed. For comparison, the benchmark scheme based on the multidimensional search method and artificial bee colony algorithm is also presented. Simulation results show that the proposed joint scheme is effective and higher EE can be obtained with lower complexity.

Self correction fractional least mean square algorithm for application in digital beamforming.

Fractional order algorithms demonstrate superior efficacy in signal processing while retaining the same level of implementation simplicity as traditional algorithms. The self-adjusting dual-stage fractional order least mean square algorithm, denoted as LFLMS, is developed to expedite convergence, improve precision, and incurring only a slight increase in computational complexity. The initial segment employs the least mean square (LMS), succeeded by the fractional LMS (FLMS) approach in the subsequent stage. The latter multiplies the LMS output, with a replica of the steering vector (Ŕ) of the intended signal. Mathematical convergence analysis and the mathematical derivation of the proposed approach are provided. Its weight adjustment integrates the conventional integer ordered gradient with a fractional-ordered. Its effectiveness is gauged through the minimization of mean square error (MSE), and thorough comparisons with alternative methods are conducted across various parameters in simulations. Simulation results underscore the superior performance of LFLMS. Notably, the convergence rate of LFLMS surpasses that of LMS by 59%, accompanied by a 49% improvement in MSE relative to LMS. So it is concluded that the LFLMS approach is a suitable choice for next generation wireless networks, including Internet of Things, 6G, radars and satellite communication.

Mitigation of Ground-Clutter Effects by Digital Beamforming With Precomputed Weighting Matrix for Phased Array Weather Radar

Mitigation of Ground-Clutter Effects by Digital Beamforming With Precomputed Weighting Matrix for Phased Array Weather Radar

Dynamic sub-array selection-based energy-efficient localization and tracking method to power implanted medical devices in scattering heterogenous media employing ultrasound.

Ultrasound (US) as a wireless power transfer methodology has drawn considerable attention from the implantable medical devices (IMD) research community. Beamforming (BF) using an external transducer array patch (ETAP) has been proposed as a robust localization scheme to find a mm-sized IMD inside the human body. However, for applications focusing on deep and shallow IMDs, optimum resource utilization at the ETAP is a major power efficiency concern for energy-constrained wearable patches. Moreover, misalignment tolerance due to IMD movements (respiratory and patient ambulatory reasons) relative to the ETAP remains a challenge. This paper presents an energy-efficient method to localize a mm-sized IMD through the dynamic selection of a sub-array within the ETAP. It is fully adaptive to the heterogeneity of the media and requires no a priori knowledge of the IMD. To improve the tolerance to IMD movements, tracking is implemented by adding and subtracting elements on the sub-array such that the sub-array electrically follows the IMD movement. Furthermore, it is shown that a minimum sampling frequency of 10X the US frequency can improve the tolerance to random noise. K-wave simulations in MATLAB are performed in different heterogenous, scattering biological media to prove the efficacy of the proposed method over standard BF methods. Measurement results in heterogenous scattering media consisting of a 3D-printed human ribs phantom and a partially blocking multipath cancellous bone phantom show an energy efficiency improvement of 10.53X and 14.4X compared to the delay-and-sum beamforming method and the unfocused transmission employing all the elements of the ETAP, respectively.

Power Optimization of Unmanned Aerial Vehicle-Assisted Future Wireless Communication Using Hybrid Beamforming Technique in Disaster Management

Several established procedures are required to be followed when responding to disasters. Although most of them have so far been successful, they pose their own set of difficulties. The primary factor is response time, which is crucial for disaster management. The use of unmanned aerial vehicles (UAVs) for wireless communication not only increases response time but also is energy efficient. However, UAVs have limited power capacities, which makes their use in wireless communication challenging. In wireless communication, hybrid beamforming is a technique for optimizing the battery consumption of unmanned aerial vehicles (UAVs). Massive MIMO technology facilitates hybrid beamforming by deploying antenna arrays, efficiently directing transmitted energy to intended receivers, and minimizing power waste. Beamforming relies heavily on accurate Channel State Information (CSI). Advanced channel estimation and tracking techniques optimize power allocation based on real-time channel conditions, thereby minimizing energy consumption and ensuring connection reliability. Hybrid beamforming combines the advantages of digital and analog beamforming to reduce power consumption while maintaining communication performance. This paper proposes a power optimization technique for UAV-based wireless communication using hybrid beamforming to maximize spectral efficiency and increase the battery life of UAVs.

Sum-Rate Maximization of RIS-Aided Digital and Holographic Beamformers in MU-MISO Systems

Sum-Rate Maximization of RIS-Aided Digital and Holographic Beamformers in MU-MISO Systems

Performance analysis of insertion loss incorporated hybrid precoding for massive MIMO

<abstract> <p>Due to an increase in the number of users and a high demand for high data rates, researchers have resorted to boosting the capacity and spectral efficiency of the next-generation wireless communication. With a limited RF chain, hybrid analog digital precoding is an appealing alternative. The hybrid precoding approach divides the beamforming process into an analog beamforming network and a digital beamforming network of a reduced size. As a result, numerous hybrid beamforming networks have been proposed. The practical effects of signal processing in the RF domain, such as the additional power loss incurred by an analog beamforming network, were not taken into account. The effectiveness of hybrid precoding structures for massive MIMO systems was examined in this study. In particular, a viable hardware network realization with insertion loss was developed. Investigating the spectral and energy efficiency of two popular hybrid precoding structures, the fully connected structure, and the subconnected structure, it was found that in a massive MIMO, the subconnected structure always performed better than the fully connected structure. Characterizing the effect of quantized analog precoding, it was shown that the subconnected structure was able to achieve better performance with fewer feedback bits than the fully connected structure.</p> </abstract>

Wavenumber Beamforming With Sub-Nyquist Sampling for Focus-Beam Ultrasound Imaging.

Conventional medical ultrasound systems utilizing focus-beam imaging generally acquire multichannel echoes at frequencies in tens of megahertz after each transmission, resulting in significant data volumes for digital beamforming. Furthermore, integrating state-of-the-art beamformers with transmission compounding substantially increases the beamforming complexity. Except for upgrading the hardware system for better computing performance, an alternative strategy for accelerating ultrasound data processing is the wavenumber beamforming algorithm, which has not been effectively extended to synthetic focus-beam transmission imaging. In this study, we propose a novel wavenumber beamforming algorithm to efficiently reduce the computational complexity of traditional focus-beam ultrasound imaging. We further integrate the wavenumber beamformer with a sub-Nyquist sampling framework, enabling ultrasonic systems to acquire echoes within the active bandwidth at significantly reduced rates. Simulation and experimental results indicate that the proposed beamformer offers image quality comparable to the state-of-the-art spatiotemporal beamformer while reducing the sampling rate and runtime by nearly ninefold and fourfold, respectively. The proposed approach would potentially help the development of low-power consumption and portable ultrasound systems.

SINR Management in Roundabout Vehicular Ad Hoc Networks: A Control and Reinforcement Learning With Digital Beamforming Approach

SINR Management in Roundabout Vehicular Ad Hoc Networks: A Control and Reinforcement Learning With Digital Beamforming Approach

Digital beamforming enhancement with LSTM-based deep learning for millimeter wave transmission

Digital beamforming enhancement with LSTM-based deep learning for millimeter wave transmission

Performance of Multiple Antenna Beamforming in Higher Constellation PSK Signaling Schemes

Performance of Multiple Antenna Beamforming in Higher Constellation PSK Signaling Schemes

Anchor Beams with Needles. An East Anglian Mystery

In central north Essex and central south Suffolk there are a number of houses dating from the fifteenth to seventeenth centuries with a form of anchor beam where, unlike those in Denmark and a number of north European countries, the protruding end is not reduced to a tenon that goes through a post, but passes through the wall undiminished with a long wedge, called here a needle, through its protruding end. These anchor beams are not attached to a post or stud but are supported by a rail. Most appear to be sixteenth or, more likely, seventeenth century, and in most cases are used either to insert a floor into an open hall of a medieval house, or of a transitional house built with an open hall heated by a chimney, or simply to remove the need for tiebeams blocking access on the first floor of low buildings. Some do act as anchor beams holding up the side walls. Apart from a few outliers, the list descriptions in the Historic England National Heritage List for England (NHLE) suggests these beams are mostly confined to north Essex and south Suffolk.

A Decoupling Technique for Beamforming Antenna Arrays Using Simple Guard Trace Structures

This paper discusses decoupling techniques for suppressing electromagnetic coupling between elements of beamforming antenna arrays. Guard trace structures, which are commonly used for crosstalk reduction on printed circuit board technology, are proposed to be inserted between the array elements for coupling reduction. Two types of guard trace structures, i.e., straight guard traces and serpentine guard traces, were explored, and the effect of using via holes on both types of guard traces was studied. For this purpose, two-element antenna arrays with guard trace structures inserted between array elements were designed and simulated. The simulation results showed that a straight guard trace with vias (straight GTV) and a serpentine guard trace without vias (serpentine GT) could effectively reduce EM coupling between elements of array antennas. To verify the simulation results, prototypes of antenna arrays with straight GTV and serpentine GT were realized and measured. The measurement results showed coupling reductions of 5 dB and 6.4 dB could be achieved when straight GTV and serpentine GT are inserted between two array elements separated by edge-to-edge distances of 4 mm and 9.05 mm, respectively. Therefore, the proposed decoupling technique is suitable for beamforming antenna arrays with a very close distance between array elements.

HYBRID BEAMFORMING FOR MULTIBEAM PHASED ARRAY RECEVIERS

In the search for enhanced wireless communication systems, multibeam phased array receivers have gained prominence. They promise to significantly boost data rates, reduce latency, and improve reliability. However, implementing multibeam receivers with traditional beamforming techniques can be challenging due to the high computational demands and the need for multiple radio frequency (RF) chains. Hybrid beamforming combines the advantages of digital and analog beamforming to strike a balance between performance and complexity. Our research delves into the following aspects of Hybrid beamforming for multibeam phased array receivers: Reduced Hardware Complexity: By blending digital and analog beamforming, we reduce the number of required RF chains, making multibeam receivers more cost-effective. Enhanced Beam Steering: Hybrid beamforming maintains precise control over multiple beams, ensuring efficient signal reception and transmission. Real-World Applications: We discuss practical applications in 5G and beyond, satellite communications, and radar systems. The paper delves into the fundamental concepts of analog and digital beamforming, illustrating their respective strengths and limitations. It then presents the architecture of hybrid beamforming systems, emphasizing the synergistic integration of analog and digital components. Special attention is given to the design considerations of beamforming networks, antenna arrays, and the beam steering mechanism. KEYWORDS Hybrid Beamforming , Phased Array , Multi-Beam , Analog Beamforming , Digital Beamforming , Beamforming Networks , Antenna Array , Beam Steering , Spatial Multiplexing , Precoding , Channel Estimation , Interference Mitigation , Power Consumption , Millimeter Wave (mmWave) , 5G and Beyond .