scholarly journals Machine Learning-Assisted Adaptive Modulation for Optimized Drone-User Communication in B5G

Drones ◽  
2021 ◽  
Vol 5 (4) ◽  
pp. 128
Author(s):  
Sudheesh Puthenveettil Gopi ◽  
Maurizio Magarini ◽  
Saeed Hamood Alsamhi ◽  
Alexey V. Shvetsov
Keyword(s):  
Machine Learning ◽  
High Speed ◽  
Degrees Of Freedom ◽  
Adaptive Modulation ◽  
Data Rate ◽  
Practical Implementation ◽  
Modulation Scheme ◽  
Error Performance ◽  
Wireless Broadcast ◽  
Atmospheric Disturbances

The fundamental issue for Beyond fifth Generation (B5G) is providing a pervasive connection to heterogeneous and various devices in smart environments. Therefore, Drones play a vital role in the B5G, allowing for wireless broadcast and high-speed communications. In addition, the drone offers several advantages compared to fixed terrestrial communications, including flexible deployment, robust Line of Sight (LoS) connections, and more design degrees of freedom due to controlled mobility. Drones can provide reliable and high data rate connectivity to users irrespective of their location. However, atmospheric disturbances impact the signal quality between drones and users and degrade the system performance. Considering practical implementation, the location of drones makes the drone–user communication susceptible to several environmental disturbances. In this paper, we evaluate the performance of drone-user connectivity during atmospheric disturbances. Further, a Machine Learning (ML)-assisted algorithm is proposed to adapt to a modulation technique that offers optimal performance during atmospheric disturbances. The results show that, with the algorithm, the system switches to a lower order modulation scheme during higher rain rate and provides reliable communication with optimized data rate and error performance.

scholarly journals Comparison Simulator Data Rate Modulation QPSK and 16 QAM System WCDMA (Wide Code Division Multiple Access) and HSDPA (High Speed Downlink Packet Access)

2015 ◽  
Vol 1 (1) ◽  
pp. 34-42
Author(s):  
Herdianna Kusuma W
Keyword(s):  
High Speed ◽  
Adaptive Modulation ◽  
Data Rate ◽  
User Equipment ◽  
Expected Improvement ◽  
Modulation Scheme ◽  
Bit Rate ◽  
Symbol Rate ◽  
Packet Access ◽  
Code Division Multiple

HSDPA (High Speed Downlink Packet Access) is the upgrade performance data packets extraordinary against WCDMA thus producing top speed 14,4 Mbps. One of the goals the creation of HSDPA is as an improvement over previous technologies. The expected improvement of HSDPA technology increasing the data rate is capable of exceeding data rate in order to WCDMA customer satisfaction in accessing multimedia content such as streaming video and data at high speed. Data Rate is the maximum data rate that can be accepted by the UE (User Equipment) in ideal conditions. One of the factors that affect the data rate is modulation scheme used by each of the technologies. QPSK modulation is used in WCDMA system and adaptive modulation (QPSK and 16QAM) is used in HSDPA system.In the research the results obtained by selection of symbol rate of 480 kbps bit rate will yield 960 kbps while the selection symbol rate is 960 kbps will produce 1920 kbps bit rate using modulation QPSK modulation. As for 16QAM modulation, symbol rate of 480 kbps produces 1920 kbps and symbol rate is 960 kbps bit rate produces 3840 kbps. Of the trial results, the more number of bits sent then the higher data rate that can be accepted by the UE (user equipment).

Modelling and Simulation of a Isoglide T3R1 Parallel Robot

2010 ◽  
Vol 166-167 ◽  
pp. 457-462
Author(s):  
Dan Verdes ◽  
Radu Balan ◽  
Máthé Koppány
Keyword(s):  
High Speed ◽  
Degrees Of Freedom ◽  
Parallel Robot ◽  
Parallel Robots ◽  
Practical Implementation ◽  
Medical Robots ◽  
The Past ◽  
And Control ◽  
Workspace Design ◽  
Human Systems

Parallel robots find many applications in human-systems interaction, medical robots, rehabilitation, exoskeletons, to name a few. These applications are characterized by many imperatives, with robust precision and dynamic workspace computation as the two ultimate ones. This paper presents kinematic analysis, workspace, design and control to 3 degrees of freedom (DOF) parallel robots. Parallel robots have received considerable attention from both researchers and manufacturers over the past years because of their potential for high stiffness, low inertia and high speed capability. Therefore, the 3 DOF translation parallel robots provide high potential and good prospects for their practical implementation in human-systems interaction.

scholarly journals Distortion losses of high-speed single-photon avalanche diode optical receivers approaching quantum sensitivity

2020 ◽  
Vol 378 (2169) ◽  
pp. 20190194 ◽  
Author(s):  
John Kosman ◽  
Kevin Moore ◽  
Harald Haas ◽  
Robert K. Henderson
Keyword(s):  
High Speed ◽  
Limit Of Detection ◽  
Single Photon ◽  
Visible Light Communication ◽  
Optical Signal ◽  
Quantum Limit ◽  
Modulation Scheme ◽  
Communication Link ◽  
Nonlinear Behaviour ◽  
Error Performance

The high internal gain of single-photon avalanche diodes (SPADs) operating in Geiger mode allows the quantum limit of detection to be approached. This offers a significantly improved sensitivity for optical communication over existing photodiodes. A fully integrated CMOS SPAD array receiver (RX) is presented which achieves 500 Mb s −1 four-level pulse amplitude modulation in a visible light communication link within 15.2 dB of the quantum limit. However, SPAD dead time induces around 5.7 dB of transient distortion which restricts error performance and data rate. We propose a model describing a discrete photon counting system which exhibits this nonlinear behaviour and compare it to practical measurements with the RX. A unipolar intensity modulated optical signal is considered, as opposed to bipolar electric fields in conventional radio frequency wireless systems. Intermodulation between the DC and harmonic components of the data-carrying waveform is investigated, and the resulting degradation of signal-to-noise-and-distortion ratio and bit error rate is evaluated. The model is developed as a tool for understanding distortion to ultimately allow rectification through RX architecture, modulation scheme, coding and equalization techniques. This article is part of the theme issue ‘Optical wireless communication’.

scholarly journals An Energy Efficient Modulation Scheme for Body-Centric Terahertz (THz) Nanonetworks

Technologies ◽  
2019 ◽  
Vol 7 (1) ◽  
pp. 14
Author(s):  
Apostolos Vavouris ◽  
Foteini Dervisi ◽  
Vasilis Papanikolaou ◽  
Panagiotis Diamantoulakis ◽  
George Karagiannidis ◽  
...  
Keyword(s):  
Data Rate ◽  
Modulation Scheme ◽  
Primary Concern ◽  
Error Performance ◽  
Specific Kind ◽  
Performance Metric ◽  
A Minor ◽  
The Impact ◽  
Time Spread ◽  
Achievable Data Rate

In body-centric communications, energy efficiency is a critical performance metric, while the achievable data rate is not of primary concern. In this paper we present a novel modulation scheme, which can be efficiently used in body-centric terahertz (THz) nanonetworks. The proposed scheme is a combination of the time-spread On-Off keying (TS–OOK) and the pulse position modulation (PPM) and presents lower energy consumption, compared to other existing methods as TS–OOK, at a minor cost to the data rate. Furthermore, another important aspect is that the proposed modulation scheme can be effectively used to mitigate the impact of the specific kind of noise in THz body-centric communications, thus leading to better error performance. Finally, we present analytical and simulation results in order to compare the new scheme with the existing TS–OOK.

scholarly journals Aerodynamics of inclined cylindrical bodies free-flying in a hypersonic flowfield

2021 ◽  
Vol 62 (9) ◽  
Author(s):  
Patrick M. Seltner ◽  
Sebastian Willems ◽  
Ali Gülhan ◽  
Eric C. Stern ◽  
Joseph M. Brock ◽  
...  
Keyword(s):  
High Speed ◽  
Degrees Of Freedom ◽  
Numerical Data ◽  
Static Stability ◽  
Free Flight ◽  
Aerodynamic Coefficients ◽  
Flow Topology ◽  
Motion Data ◽  
Continuous Rotation ◽  
German Aerospace

Abstract The influence of the flight attitude on aerodynamic coefficients and static stability of cylindrical bodies in hypersonic flows is of interest in understanding the re/entry of space debris, meteoroid fragments, launch-vehicle stages and other rotating objects. Experiments were therefore carried out in the hypersonic wind tunnel H2K at the German Aerospace Center (DLR) in Cologne. A free-flight technique was employed in H2K, which enables a continuous rotation of the cylinder without any sting interferences in a broad angular range from 0$$^{\circ }$$ ∘ to 90$$^{\circ }$$ ∘ . A high-speed stereo-tracking technique measured the model motion during free-flight and high-speed schlieren provided documentation of the flow topology. Aerodynamic coefficients were determined in careful post-processing, based on the measured 6-degrees-of-freedom (6DoF) motion data. Numerical simulations by NASA’s flow solvers Cart3D and US3D were performed for comparison purposes. As a result, the experimental and numerical data show a good agreement. The inclination of the cylinder strongly effects both the flowfield and aerodynamic loads. Experiments and simulations with concave cylinders showed marked difference in aerodynamic behavior due to the presence of a shock–shock interaction (SSI) near the middle of the model. Graphic abstract

scholarly journals A 1.55-to-32-Gb/s Four-Lane Transmitter with 3-Tap Feed Forward Equalizer and Shared PLL in 28-nm CMOS

Electronics ◽  
2021 ◽  
Vol 10 (16) ◽  
pp. 1873
Author(s):  
Chen Cai ◽  
Xuqiang Zheng ◽  
Yong Chen ◽  
Danyu Wu ◽  
Jian Luan ◽  
...  
Keyword(s):  
Data Transmission ◽  
High Speed ◽  
Data Rate ◽  
Quality Data ◽  
Cmos Process ◽  
Voltage Controlled Oscillator ◽  
Feed Forward ◽  
Fully Integrated ◽  
Output Driver ◽  
28 Nm

This paper presents a fully integrated physical layer (PHY) transmitter (TX) suiting for multiple industrial protocols and compatible with different protocol versions. Targeting a wide operating range, the LC-based phase-locked loop (PLL) with a dual voltage-controlled oscillator (VCO) was integrated to provide the low jitter clock. Each lane with a configurable serialization scheme was adapted to adjust the data rate flexibly. To achieve high-speed data transmission, several bandwidth-extended techniques were introduced, and an optimized output driver with a 3-tap feed-forward equalizer (FFE) was proposed to accomplish high-quality data transmission and equalization. The TX prototype was fabricated in a 28-nm CMOS process, and a single-lane TX only occupied an active area of 0.048 mm2. The shared PLL and clock distribution circuits occupied an area of 0.54 mm2. The proposed PLL can support a tuning range that covers 6.2 to 16 GHz. Each lane's data rate ranged from 1.55 to 32 Gb/s, and the energy efficiency is 1.89 pJ/bit/lane at a 32-Gb/s data rate and can tune an equalization up to 10 dB.

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