Acoustic Beam Characterization and Selection for Optimized Underwater Communication

2019 ◽  
Vol 9 (13) ◽  
pp. 2740
Author(s):  
Akram Ahmed ◽  
Mohamed Younis
Keyword(s):  
Three Dimensional ◽  
Underwater Communication ◽  
Coverage Area ◽  
Directional Transmission ◽  
Beam Characterization ◽  
Communication Links ◽  
Beam Selection ◽  
Signal Detectability ◽  
Selection For ◽  
Underwater Acoustic Signal

To increase underwater acoustic signal detectability and conserve energy, nodes leverage directional transmissions. In addition, nodes operate in a three-dimensional (3D) environment that is categorized as inhomogeneous where a propagating signal changes its direction based on the observed sound speed profile (SSP). Coupling 3D directional transmission with frequent node drifts and the varying underwater SSP complicates the process of selecting suitable transmission angles to maintain underwater communication links. Fundamentally, utilizing directional transmission while nodes are drifting causes breaks in established communication links and thus nodes need to find new angles to reestablish these links. Moreover, selecting arbitrary transmission angles may lead to overlapping beams or result in leaving an underwater region uncovered. To tackle the abovementioned challenges, this paper proposes an autonomous beam selection approach that optimizes underwater communication by selecting non-overlapping beams while mitigating the possibility of missing a region, i.e., maximize coverage. Such optimization is achieved by utilizing a structured angle selection mechanism that accounts for the capability of the used transducer. Moreover, we introduce an algorithm suited for resource constrained nodes to classify rays into different types. Then we divide the underwater medium into regions where each region is identified by the limits of the coverage area of each ray type. Finally, we utilize the limits of these regions to aid nodes in selecting the best ray to reestablish communication with drifted nodes. We validate our contribution through simulation where actual SSPs are leveraged to validate the beam classification process.

scholarly journals A 3-dimensional fast machine learning algorithm for mobile unmanned aerial vehicle base stations

2021 ◽  
Vol 10 (1) ◽  
pp. 28
Author(s):  
Wasswa Shafik ◽  
S. Motjaba Matinkhah ◽  
Solagbade Saheed Afolabi ◽  
Mamman Nur Sanda
Keyword(s):  
Millimeter Wave ◽  
Learning Algorithm ◽  
Base Stations ◽  
3 Dimensional ◽  
Environmental Responsiveness ◽  
Directional Transmission ◽  
Communication Links ◽  
Beam Selection ◽  
Aerial Vehicle ◽  
Selection For

<p>The 5G technology is predicted to achieve the unoptimized millimeter Wave (mmWave) of 30-300 GHz bands. This unoptimized band because of the loss of mm-Wave bands, like path attenuation and propagation losses. Nonetheless, because of: (i) directional transmission paving way for beamforming to recompense for the path attenuation, and (ii) sophisticated placement concreteness of the base stations (BS) is the best alternative for array wireless communications in mmWave bands (that is to say 100-150 m). The advance in technology and innovation of unmanned aerial vehicles (UAVs) necessitates many opportunities and uncertainties. UAVs are agile and can fly all complexities if the terrains making ground robots unsuitable. The UAV may be managed either independently through aboard computers or distant controlled of a flight attendant on pulverized wireless communication links in our case 5G. Although a fast algorithm solved the problematic aspect of beam selection for 2-dimensional scenarios. This paper presents 3-dimensional scenarios for UAV. We modeled beam selection with environmental responsiveness in millimeter Wave UAV to accomplish close optimum assessments on the regular period through learning from the available situation.</p>

Three-dimensional (3D) printed scaffold and material selection for bone repair

2019 ◽  
Vol 84 ◽  
pp. 16-33 ◽  
Author(s):  
Lei Zhang ◽  
Guojing Yang ◽  
Blake N. Johnson ◽  
Xiaofeng Jia
Keyword(s):  
Bone Repair ◽  
Material Selection ◽  
Three Dimensional ◽  
3D Printed ◽  
Selection For

Interference-Aware Random Beam Selection for Spectrum Sharing Systems

2012 ◽  
Author(s):  
Mohamed Abdallah ◽  
Mostafa Sayed ◽  
Mohamed-Slim Alouini ◽  
Khalid A. Qaraqe
Keyword(s):  
Spectrum Sharing ◽  
Beam Selection ◽  
Selection For

scholarly journals Srna - Monte Carlo codes for proton transport simulation in combined and voxelized geometries

2002 ◽  
Vol 17 (1-2) ◽  
pp. 27-36 ◽  
Author(s):  
Radovan Ilic ◽  
Darko Lalic ◽  
Srboljub Stankovic
Keyword(s):  
Monte Carlo ◽  
Proton Transport ◽  
Transition Probabilities ◽  
Three Dimensional ◽  
Monte Carlo Techniques ◽  
Transport Simulation ◽  
Distribution Calculation ◽  
Beam Characterization ◽  
Positron Emitters ◽  
Tomography Data

This paper describes new Monte Carlo codes for proton transport simulations in complex geometrical forms and in materials of different composition. The SRNA codes were developed for three dimensional (3D) dose distribution calculation in proton therapy and dosimetry. The model of these codes is based on the theory of proton multiple scattering and a simple model of compound nucleus decay. The developed package consists of two codes: SRNA-2KG and SRNA-VOX. The first code simulates proton transport in combined geometry that can be described by planes and second order surfaces. The second one uses the voxelized geometry of material zones and is specifically adopted for the application of patient computer tomography data. Transition probabilities for both codes are given by the SRNADAT program. In this paper, we will present the models and algorithms of our programs, as well as the results of the numerical experiments we have carried out applying them, along with the results of proton transport simulation obtained through the PETRA and GEANT programs. The simulation of the proton beam characterization by means of the Multi-Layer Faraday Cup and spatial distribution of positron emitters obtained by our program indicate the imminent application of Monte Carlo techniques in clinical practice.

scholarly journals Joint 3-D Positioning and Power Allocation for UAV Relay Aided by Geographic Information

2021 ◽  
Author(s):  
Pengfei Yi ◽  
Liang Zhu ◽  
Lipeng Zhu ◽  
Zhenyu Xiao
Keyword(s):  
Power Allocation ◽  
Upper Bound ◽  
Three Dimensional ◽  
Geographic Information ◽  
Base Station ◽  
Lagrangian Multipliers ◽  
Loop Optimization ◽  
Convex Problem ◽  
Communication Links ◽  
Minimum Capacity

<div>In this paper, we study to employ geographic information to address the blockage problem of air-to-ground links between UAV and terrestrial nodes. In particular, a UAV relay is deployed to establish communication links from a ground base station to multiple ground users. To improve communication capacity, we fifirst model the blockage effect caused by buildings according to the three-dimensional (3-D) geographic information. Then, an optimization problem is formulated to maximize the minimum capacity among users by jointly optimizing the 3-D position and power allocation of the UAV relay, under the constraints of link capacity, maximum transmit power, and blockage. To solve this complex non-convex problem, a two-loop optimization framework is developed based on Lagrangian relaxation. The outer-loop aims to obtain proper Lagrangian multipliers to ensure the solution of the Lagrangian problem converge to the tightest upper bound on the original problem. The inner-loop solves the Lagrangian problem by applying the block coordinate descent (BCD) and successive convex approximation (SCA) techniques, where UAV 3-D positioning and power allocation are alternately optimized in each iteration. Simulation results confifirm that the proposed solution signifificantly outperforms two benchmark schemes and achieves a performance close to the upper bound on the UAV relay system.</div>

Beam Selection for Cell-free Millimeter-Wave Massive MIMO Systems

2021 ◽  
Author(s):  
Qiulin Xue ◽  
Qingqing Li ◽  
Chao Dong ◽  
Shiqiang Suo ◽  
Kai Niu
Keyword(s):  
Millimeter Wave ◽  
Massive Mimo ◽  
Mimo Systems ◽  
Beam Selection ◽  
Selection For

Performance of Opportunistic Beam Selection for OWC System Under Foggy Channel with Pointing Error

2020 ◽  
Vol 24 (9) ◽  
pp. 2029-2033
Author(s):  
Ziyaur Rahman ◽  
Syed Mohammad Zafaruddin ◽  
Vinod Kumar Chaubey
Keyword(s):  
Pointing Error ◽  
Beam Selection ◽  
Selection For

Handoff Schemes in Mobile Environments

2020 ◽  
Vol 11 (1) ◽  
pp. 55-72
Author(s):  
Libin Thomas ◽  
J Sandeep ◽  
Bhargavi Goswami ◽  
Joy Paulose
Keyword(s):  
Ad Hoc Networks ◽  
Vehicular Ad Hoc Networks ◽  
Ad Hoc ◽  
Mobile Environments ◽  
Mobile Nodes ◽  
Mobile Environment ◽  
Coverage Area ◽  
Communication Links ◽  
Hoc Networks ◽  
Handoff Schemes

Vehicular ad-hoc networks are one of the most popular applications of Ad-hoc networks, where networks are formed without any sort of physical connecting medium and can be formed whenever required. It is an area in networks that has enjoyed a considerable amount of attention for quite some time. Due to the highly mobile environment where these networks find their usability, it can be understood that there are a lot of problems with respect to maintaining the communication links between the moving vehicular nodes and the static infrastructures which act as the access points (AP) for these moving vehicular mobile nodes (MN). The coverage area of each AP is limited and as such, the connections need to be re-established time and again between the MNs and the closest accessible AP. Handoff is the process involved here, which deals with selecting the optimal APs as well as the best network available for data transmission. In this article, the authors compare various handoff methods and categorize them based on the different approaches they follow.

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