The fifth generation (5G) wireless communication networks are being deployed worldwide from 2020 and more capabilities are in the process of being standardized, such as mass connectivity, ultra-reliability, and guaranteed low latency. However, 5G will not meet all requirements of the future in 2030 and beyond, and sixth generation (6G) wireless communication networks are expected to provide global coverage, enhanced spectral/energy/cost efficiency, better intelligence level and security, etc. To meet these requirements, 6G networks will rely on new enabling technologies, i.e., air interface and transmission technologies and novel network architecture, such as waveform design, multiple access, channel coding schemes, multi-antenna technologies, network slicing, cell-free architecture, and cloud/fog/edge computing. Our vision on 6G is that it will have four new paradigm shifts. First, to satisfy the requirement of global coverage, 6G will not be limited to terrestrial communication networks, which will need to be complemented with non-terrestrial networks such as satellite and unmanned aerial vehicle (UAV) communication networks, thus achieving a space-air-ground-sea integrated communication network. Second, all spectra will be fully explored to further increase data rates and connection density, including the sub-6 GHz, millimeter wave (mmWave), terahertz (THz), and optical frequency bands. Third, facing the big datasets generated by the use of extremely heterogeneous networks, diverse communication scenarios, large numbers of antennas, wide bandwidths, and new service requirements, 6G networks will enable a new range of smart applications with the aid of artificial intelligence (AI) and big data technologies. Fourth, network security will have to be strengthened when developing 6G networks. This article provides a comprehensive survey of recent advances and future trends in these four aspects. Clearly, 6G with additional technical requirements beyond those of 5G will enable faster and further communications to the extent that the boundary between physical and cyber worlds disappears.

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Towards 6G wireless communication networks: vision, enabling technologies, and new paradigm shifts

Unmanned aerial vehicles (UAVs) have found numerous applications and are expected to bring fertile business opportunities in the next decade. Among various enabling technologies for UAVs, wireless communication is essential and has drawn significantly growing attention in recent years. Compared to the conventional terrestrial communications, UAVs’ communications face new challenges due to their high altitude above the ground and great flexibility of movement in the 3-D space. Several critical issues arise, including the line-of-sight (LoS) dominant UAV-ground channels and induced strong aerial-terrestrial network interference, the distinct communication quality-of-service (QoS) requirements for UAV control messages versus payload data, the stringent constraints imposed by the size, weight, and power (SWAP) limitations of UAVs, as well as the exploitation of the new design degree of freedom (DoF) brought by the highly controllable 3-D UAV mobility. In this article, we give a tutorial overview of the recent advances in UAV communications to address the above issues, with an emphasis on how to integrate UAVs into the forthcoming fifth-generation (5G) and future cellular networks. In particular, we partition our discussion into two promising research and application frameworks of UAV communications, namely UAV-assisted wireless communications and cellular-connected UAVs, where UAVs are integrated into the network as new aerial communication platforms and users, respectively. Furthermore, we point out promising directions for future research.

Accessing From the Sky: A Tutorial on UAV Communications for 5G and Beyond

A compilation of UAV applications for precision agriculture

Himalayan glacier tongues are commonly debris covered and they are an important source of melt water. However, they remain relatively unstudied because of the inaccessibility of the terrain and the difficulties in field work caused by the thick debris mantles. Observations of debris-covered glaciers are therefore scarce and airborne remote sensing may bridge the gap between scarce field observations and coarse resolution space-borne remote sensing. In this study we deploy an Unmanned Aerial Vehicle (UAV) before and after the melt and monsoon season (May and October 2013) over the debris-covered tongue of the Lirung Glacier in Nepal. Based on stereo-imaging and the structure for motion algorithm we derive highly detailed ortho-mosaics and digital elevation models (DEMs), which we geometrically correct using differential GPS observations collected in the field. Based on DEM differencing and manual feature tracking we derive the mass loss and the surface velocity of the glacier at a high spatial accuracy. On average, mass loss is limited and the surface velocity is very small. However, the spatial variability of melt rates is very high, and ice cliffs and supra-glacial ponds show mass losses that can be an order of magnitude higher than the average. We suggest that future research should focus on the interaction between supra-glacial ponds, ice cliffs and englacial hydrology to further understand the dynamics of debris-covered glaciers. Finally, we conclude that UAV deployment has large potential in glaciology and it may revolutionize methods currently applied in studying glacier surface features.

High-Resolution Monitoring of Himalayan Glacier Dynamics Using Unmanned Aerial Vehicles

Unmanned aerial vehicles (UAVs) have found numerous applications and are expected to bring fertile business opportunities in the next decade. Among various enabling technologies for UAVs, wireless communication is essential and has drawn significantly growing attention in recent years. Compared to the conventional terrestrial communications, UAVs' communications face new challenges due to their high altitude above the ground and great flexibility of movement in the three-dimensional (3D) space. Several critical issues arise, including the line-of-sight (LoS) dominant UAV-ground channels and resultant strong aerial-terrestrial network interference, the distinct communication quality of service (QoS) requirements for UAV control messages versus payload data, the stringent constraints imposed by the size, weight and power (SWAP) limitations of UAVs, as well as the exploitation of the new design degree of freedom (DoF) brought by the highly controllable 3D UAV mobility. In this paper, we give a tutorial overview of the recent advances in UAV communications to address the above issues, with an emphasis on how to integrate UAVs into the forthcoming fifth-generation (5G) and future cellular networks. In particular, we partition our discussions into two promising research and application frameworks of UAV communications, namely UAV-assisted wireless communications and cellular-connected UAVs,where UAVs serve as aerial communication platforms and users, respectively. Furthermore, we point out promising directions for future research and investigation.

Accessing From The Sky: A Tutorial on UAV Communications for 5G and Beyond

Impact study of integrating solar double chimney power plant into electrical grid

Battery energy storage systems (BESSs) are considered one of the most developed energy storage system (ESS) technologies because they have different benefits for distribution networks like smoothening the output fluctuations, improving the power quality, peak load shifting, voltage support and delaying the distribution network upgrade. This work involves integrating a BESS into a 33 KV distribution network in Jordan. CYME software is used to assess the impact of BESS at Almanara PV power plant on the 33 KV medium voltage network. The voltage level, power losses, power factor (PF) and voltage step are chosen as performance indicators. For each of these indices, comparisons between the grid performance with and without the BESS are carried out. In addition, the payback period of the BESS is calculated. The obtained results reveal that BESS not only improves the voltage level – with an overall improvement of about 3.03% at both feeders – but also reduces the losses, with an overall reduction in losses of 4.68% at both feeders. BESS is found to decrease the PF with an average of 0.83 at both feeders, while the voltage step doesn’t exceed the limits set by the International Electro-technical Commission (IEC). Additionally, the performed economic analysis unveils that the payback period is about 10.98 years.

Techno-Economic Feasibility Analysis of On-Grid Battery Energy Storage System: Almanara PV Power Plant Case Study

In this paper, a novel dual-function grid-connected solar inverter is developed for better utility interaction applications. The proposed topology is able to inject active power, reactive power, and mitigate harmonic problems caused by non-linear loads. The proposed configuration consists of switched LC-connected inverter (SLC-CI) in parallel with static VAR compensator (SVC) to achieve the design requirements. The system description, mathematical model, control algorithm, and parameter design of the proposed system is systematically developed to ensure acceptable performance. The system performance is evaluated with both linear and non-linear loads and compared to two conventional topologies; inductive and capacitive grid connected inverters. The results demonstrate that the proposed topology have better performance, comparing to other topologies, in terms of using lower DC-bus voltage (25% less) and using around half the power rating of inverter. Moreover, the proposed double switched LC filter-connected inverter (DSLC-CI) shows its ability to work as active power filter and mitigate harmonics to acceptable level.

https://ijrer.com/index.php/ijrer/article/download/12055/pdf

Design and Control of A Novel Dual Function Grid-Connected Solar Inverter

In this paper, An adaptiveRadial Basis Function Neural Networks (RBFNN)algorithm is used to estimate the fundamental and harmonic components of nonlinear load current. The learning rates for adaptive RBFNN are further investigated to minimize the total error and to minimize the error in each of the fundamental and harmonics components. The performance of the adaptive RBFNN is evaluated based on the difference between the original signal and the constructed signal (the summation between fundamental and harmonic components). The methodology used in this paper facilitates the development and design of signal processing and control systems. This is done by training the system and obtaining the initial parameters for the RBFNN based on simulation. After that, the adaptive RBFNN can be in the real system with these initial parameters.

Eyad Almaita

Papers

Impact study of integrating solar double chimney power plant into electrical grid

Techno-Economic Feasibility Analysis of On-Grid Battery Energy Storage System: Almanara PV Power Plant Case Study

Design and Control of A Novel Dual Function Grid-Connected Solar Inverter

Facilitating On-Line Harmonic Estimation Based on Robust Adaptive RBFNN