scholarly journals Efficient Radio Channel Allocation in Integrated mmWave/Sub-6 GHz UAV-Assisted Disaster Relief Networks

2021 ◽  
Vol 2021 ◽  
pp. 1-18
Author(s):  
Jinsong Gui ◽  
Fujian Cai
Keyword(s):  
Energy Efficiency ◽  
Frequency Band ◽  
High Speed ◽  
Channel Allocation ◽  
Disaster Relief ◽  
Radio Channel ◽  
Path Loss ◽  
Convergence Time ◽  
Propagation Path ◽  
Interference Graph

The unmanned aerial vehicle- (UAV-) assisted sub-6 GHz disaster relief networks cannot meet high-speed transmission requirements. In this paper, the millimeter wave (mmWave) frequency band is combined with the sub-6 GHz frequency band to build a high-speed UAV-assisted disaster relief network. However, the high propagation path loss of mmWave signals usually needs to be compensated by beamforming, where the ground-facing beam of each UAV is the desired receiving beam of ground user information. The different channels need to be allocated to a single UAV so that this kind of beam can be used simultaneously by different ground users to communicate with this UAV. Also, the other UAVs should reuse these channels as much as possible to save spectrum resources. In this paper, the beamforming training (BFT) mechanism is firstly used to obtain the signal-to-noise ratio (SNR) values of all possible links between ground terminals and UAVs, which are used to estimate these links’ energy efficiency. Then, an interference graph construction algorithm is proposed to identify the links that cannot be used simultaneously in the same channel according to the system energy efficiency. Finally, an iterative channel allocation algorithm is designed to allocate new channels to eliminate the edges of the interference graph, so that the links obtained by the BFT process can be used simultaneously as much as possible under the constraint of the number of channels. The simulation results show that our proposed scheme can achieve the shorter average convergence time, the higher data rate (or the lower data loss rate), and the higher energy efficiency.

scholarly journals Joint UAV channel modeling and power control for 5G IoT networks

2021 ◽  
Vol 2021 (1) ◽  
Author(s):  
Xiuhua Fu ◽  
Tian Ding ◽  
Rongqun Peng ◽  
Cong Liu ◽  
Mohamed Cheriet
Keyword(s):  
Energy Efficiency ◽  
Power Control ◽  
Channel Model ◽  
Path Loss ◽  
Channel Modeling ◽  
Signal Propagation ◽  
Spectrum Efficiency ◽  
Propagation Path ◽  
Control Factor ◽  
The Impact

AbstractThis paper studies the communication problem between UAVs and cellular base stations in a 5G IoT scenario where multiple UAVs work together. We are dedicated to the uplink channel modeling and the performance analysis of the uplink transmission. In the channel model, we consider the impact of 3D distance and multi-UAVs reflection on wireless signal propagation. The 3D distance is used to calculate the path loss, which can better reflect the actual path loss. The power control factor is used to adjust the UAV's uplink transmit power to compensate for different propagation path losses, so as to achieve precise power control. This paper proposes a binary exponential power control algorithm suitable for 5G networked UAV transmitters and presents the entire power control process including the open-loop phase and the closed-loop phase. The effects of power control factors on coverage probability, spectrum efficiency and energy efficiency under different 3D distances are simulated and analyzed. The results show that the optimal power control factor can be found from the point of view of energy efficiency.

INNOVATIVE METHOD OF SATELLITE COMMUNICATION

2019 ◽  
Author(s):  
Teodor Narytnik ◽  
Vladimir Saiko
Keyword(s):  
Communication Systems ◽  
High Speed ◽  
Satellite Communication ◽  
Radio Channel ◽  
Satellite Communications ◽  
Service Area ◽  
Satellite Systems ◽  
Orbit Satellite ◽  
Geometric Size ◽  
Distributed Satellite

The technical aspects of the main promising projects in the segments of medium and low-orbit satellite communication systems are considered, as well as the project of the domestic low-orbit information and telecommunications system using the terahertz range, which is based on the use of satellite platforms of the micro- and nanosatellite class and the distribution of functional blocks of complex satellite payloads more high-end on multiple functionally related satellites. The proposed system of low-orbit satellite communications represents the groupings of low-orbit spacecraft (LEO-system) with the architecture of a "distributed satellite", which include the groupings of the root (leading) satellites and satellite repeaters (slaves). Root satellites are interconnected in a ring network by high-speed links between the satellites. The geometric size of the “distributed satellite” is the area around the root satellite with a radius of about 1 km. The combination of beams, which are formed by the repeater satellites, make up the service area of the LEO system. The requirements for the integrated service area of the LEO system (geographical service area) determine the requirements for the number of distributed satellites in the system as a whole. In the proposed system to reduce mutual interference between the grouping of the root (leading) satellites and repeater satellites (slaves) and, accordingly, minimizing distortions of the information signal when implementing inter-satellite communication, this line (radio channel) was created in an unlicensed frequency (e.g., in the terahertz 140 GHz) range. In addition, it additionally allows you to minimize the size of the antennas of such a broadband channel and simplify the operation of these satellite systems.

scholarly journals Prognostic Assessment of the Performance Parameters for the Industrial Diesel Engines Operated with Microalgae Oil

2021 ◽  
Vol 13 (11) ◽  
pp. 6482
Author(s):  
Sergejus Lebedevas ◽  
Laurencas Raslavičius
Keyword(s):  
Energy Efficiency ◽  
Diesel Engine ◽  
High Speed ◽  
Performance Parameters ◽  
Prognostic Assessment ◽  
High Speed Diesel ◽  
Microalgae Oil ◽  
The Difference ◽  
Smoke Opacity ◽  
Efficiency Indicators

A study conducted on the high-speed diesel engine (bore/stroke: 79.5/95.5 mm; 66 kW) running with microalgae oil (MAO100) and diesel fuel (D100) showed that, based on Wibe parameters (m and φz), the difference in numerical values of combustion characteristics was ~10% and, in turn, resulted in close energy efficiency indicators (ηi) for both fuels and the possibility to enhance the NOx-smoke opacity trade-off. A comparative analysis by mathematical modeling of energy and traction characteristics for the universal multi-purpose diesel engine CAT 3512B HB-SC (1200 kW, 1800 min−1) confirmed the earlier assumption: at the regimes of external speed characteristics, the difference in Pme and ηi for MAO100 and D100 did not exceeded 0.7–2.0% and 2–4%, respectively. With the refinement and development of the interim concept, the model led to the prognostic evaluation of the suitability of MAO100 as fuel for the FPT Industrial Cursor 13 engine (353 kW, 6-cylinders, common-rail) family. For the selected value of the indicated efficiency ηi = 0.48–0.49, two different combinations of φz and m parameters (φz = 60–70 degCA, m = 0.5 and φz = 60 degCA, m = 1) may be practically realized to achieve the desirable level of maximum combustion pressure Pmax = 130–150 bar (at α~2.0). When switching from diesel to MAO100, it is expected that the ηi will drop by 2–3%, however, an existing reserve in Pmax that comprises 5–7% will open up room for further optimization of energy efficiency and emission indicators.

scholarly journals Deterministic and Empirical Approach for Millimeter-Wave Complex Outdoor Smart Parking Solution Deployments

Sensors ◽  
2021 ◽  
Vol 21 (12) ◽  
pp. 4112
Author(s):  
Fidel Alejandro Rodríguez-Corbo ◽  
Leyre Azpilicueta ◽  
Mikel Celaya-Echarri ◽  
Peio Lopez-Iturri ◽  
Ana V. Alejos ◽  
...  
Keyword(s):  
Large Scale ◽  
Radio Channel ◽  
Path Loss ◽  
Ground Level ◽  
Directional Antennas ◽  
Scale Parameters ◽  
Parking Lot ◽  
Smart Parking ◽  
Wireless Communications Systems

The characterization of different vegetation/vehicle densities and their corresponding effects on large-scale channel parameters such as path loss can provide important information during the deployment of wireless communications systems under outdoor conditions. In this work, a deterministic analysis based on ray-launching (RL) simulation and empirical measurements for vehicle-to-infrastructure (V2I) communications for outdoor parking environments and smart parking solutions is presented. The study was carried out at a frequency of 28 GHz using directional antennas, with the transmitter raised above ground level under realistic use case conditions. Different radio channel impairments were weighed in, considering the progressive effect of first, the density of an incremental obstructed barrier of trees, and the effect of different parked vehicle densities within the parking lot. On the basis of these scenarios, large-scale parameters and temporal dispersion characteristics were obtained, and the effect of vegetation/vehicle density changes was assessed. The characterization of propagation impairments that different vegetation/vehicle densities can impose onto the wireless radio channel in the millimeter frequency range was performed. Finally, the results obtained in this research can aid communication deployment in outdoor parking conditions.

scholarly journals A Tutorial on Optical Feeding of Millimeter-Wave Phased Array Antennas for Communication Applications

2015 ◽  
Vol 2015 ◽  
pp. 1-22 ◽  
Author(s):  
Ivan Aldaya ◽  
Gabriel Campuzano ◽  
Gerardo Castañón ◽  
Alejandro Aragón-Zavala
Keyword(s):  
Millimeter Wave ◽  
High Speed ◽  
Phased Array ◽  
Path Loss ◽  
High Gain ◽  
Interference Avoidance ◽  
Amplitude Control ◽  
Phased Array Antennas ◽  
Array Antennas ◽  
The Impact

Given the interference avoidance capacity, high gain, and dynamical reconfigurability, phased array antennas (PAAs) have emerged as a key enabling technology for future broadband mobile applications. This is especially important at millimeter-wave (mm-wave) frequencies, where the high power consumption and significant path loss impose serious range constraints. However, at mm-wave frequencies the phase and amplitude control of the feeding currents of the PAA elements is not a trivial issue because electrical beamforming requires bulky devices and exhibits relatively narrow bandwidth. In order to overcome these limitations, different optical beamforming architectures have been presented. In this paper we review the basic principles of phased arrays and identify the main challenges, that is, integration of high-speed photodetectors with antenna elements and the efficient optical control of both amplitude and phase of the feeding current. After presenting the most important solutions found in the literature, we analyze the impact of the different noise sources on the PAA performance, giving some guidelines for the design of optically fed PAAs.

scholarly journals Broadband Wireless Channel in Composite High-Speed Railway Scenario: Measurements, Simulation, and Analysis

2017 ◽  
Vol 2017 ◽  
pp. 1-15 ◽  
Author(s):  
Jianwen Ding ◽  
Lei Zhang ◽  
Jingya Yang ◽  
Bin Sun ◽  
Jiying Huang
Keyword(s):  
Ray Tracing ◽  
Communication Systems ◽  
High Speed ◽  
Channel Model ◽  
High Reliability ◽  
Rapid Development ◽  
Path Loss ◽  
Wireless Channel ◽  
Delay Spread ◽  
High Speed Railway

The rapid development of high-speed railway (HSR) and train-ground communications with high reliability, safety, and capacity promotes the evolution of railway dedicated mobile communication systems from Global System for Mobile Communications-Railway (GSM-R) to Long Term Evolution-Railway (LTE-R). The main challenges for LTE-R network planning are the rapidly time-varying channel and high mobility, because HSR lines consist of a variety of complex terrains, especially the composite scenarios where tunnels, cuttings, and viaducts are connected together within a short distance. Existing researches mainly focus on the path loss and delay spread for the individual HSR scenarios. In this paper, the broadband measurements are performed using a channel sounder at 950 MHz and 2150 MHz in a typical HSR composite scenario. Based on the measurements, the pivotal characteristics are analyzed for path loss exponent, power delay profile, and tap delay line model. Then, the deterministic channel model in which the 3D ray-tracing algorithm is applied in the composite scenario is presented and validated by the measurement data. Based on the ray-tracing simulations, statistical analysis of channel characteristics in delay and Doppler domain is carried out for the HSR composite scenario. The research results can be useful for radio interface design and optimization of LTE-R system.

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