Performance analysis of micro unmanned airborne communication relays for cellular networks (original) (raw)

Wireless relay communications with unmanned aerial vehicles: Performance and optimization

Aerospace and Electronic …, 2011

In this paper, we investigate a communication system in which Unmanned Aerial Vehicles (UAVs) are used as relays between ground-based terminals and a network basestation. We develop an algorithm for optimizing the performance of the ground-to-relay links through control of the UAV heading angle. To quantify link performance, we define the Ergodic Normalized Transmission Rate (ENTR) for the links between the ground nodes and the relay, and derive a closed-form expression for it in terms of the eigenvalues of the channel correlation matrix. We show that the ENTR can be approximated as a sinusoid with an offset that depends on the heading of the UAV. Using this observation, we develop a closed-form expression for the UAV heading that maximizes the uplink network data rate while keeping the rate of each individual link above a certain threshold. When the current UAV relay assignments cannot meet the minimum link requirements, we investigate the deployment and heading control problem for new UAV relays as they are added to the network, and propose a smart handoff algorithm that updates node and relay assignments as the topology of the network evolves.

Efficient Placement of an Aerial Relay Drone for Throughput Maximization

2021

Unmanned aerial vehicle (UAV) communication can be used in overcrowded areas and either during or postdisaster situations as an evolving technology to provide ubiquitous connections for wireless devices due to its flexibility, mobility, and good condition of the line of sight channels. In this paper, a single UAV is used as an aerial relay node to provide connectivity to wireless devices because of the considerable distance between wireless devices and the ground base station. Specifically, two path loss models have been utilized; a cellular-to-UAV path loss for a backhaul connection and an air-to-ground path loss model for a downlink connection scenario. Then, the tradeoff introduced by these models is discussed. The problem of efficient placement of an aerial relay node is formulated as an optimization problem, where the objective is to maximize the total throughput of wireless devices. To find an appropriate location for a relay aerial node that maximizes the overall throughput, ...

A Review of Relay Network on Uavs for Enhanced Connectivity

Jurnal Teknologi, 2019

One of the best evolution in technology breakthroughs is the Unmanned Aerial Vehicle (UAV). This aerial system is able to perform the mission in an agile environment and can reach the hard areas to perform the tasks autonomously. UAVs can be used in post-disaster situations to estimate damages, to monitor and to respond to the victims. The Ground Control Station can also provide emergency messages and ad-hoc communication to the Mobile Users of the disaster-stricken community using this network. A wireless network can also extend its communication range using UAV as a relay. Major requirements from such networks are robustness, scalability, energy efficiency and reliability. In general, UAVs are easy to deploy, have Line of Sight options and are flexible in nature. However, their 3D mobility, energy constraints, and deployment environment introduce many challenges. This paper provides a discussion of basic UAV based multi-hop relay network architecture and analyses their benefits, a...

Performance Evaluation of Next-Generation Wireless (5G) UAV Relay

Wireless Personal Communications, 2020

Future wireless communication, especially the densified 5G network using millimeter-Wave (mmWave) will bring numerous innovations to the current telecommunication industry. In such scenario, the use of Unmanned Aerial Vehicle (UAV) as Base Station (BS) becomes one of the viable options for providing 5G services. The focus of this study is to investigate, analyze and describe the distinctive rich characteristics of mmWave propagation in Access and backhaul network simultaneously using UAV. The mathematical framework is formulated for calculating UE (User Equipment) received power for the relay path (BS-UAV-UE) based on Friis Transmission Equation. We conduct simulations using the ray-tracing simulator in different scenarios while comparing and verifying the simulation results vs mathematical equations. Using ray racing simulator, the effectiveness of diffracted, reflected, and scattered paths versus direct paths is described. Furthermore, using extensive simulations, we highlight the impact of UAV location to maximize the performance of an Amplify-and-Forward UAV based relay for providing enhanced coverage to the users. Keywords Unnamed aerial vehicle (UAV) • Key point indicator (KPI) • MmWave • Unmanned aerial systems (UAS) • Aerial network (AN) • 5G

High Throughput Data Relay in UAV Wireless Networks

Future Internet

As a result of their high mobility and reduced cost, Unmanned Aerial Vehicles (UAVs) have been found to be a promising tool in wireless networks. A UAV can perform the role of a base station as well as a mobile relay, connecting distant ground terminals. In this paper, we dispatch a UAV to a disaster area to help relay information for victims. We involve a bandwidth efficient technique called the Dual-Sampling (DS) method when planning the UAV flight trajectory, trying to maximize the data transmission throughput. We propose an iterative algorithm for solving this problem. The victim bandwidth scheduling and the UAV trajectory are alternately optimized in each iteration, meanwhile a power balance mechanism is implemented in the algorithm to ensure the proper functioning of the DS method. We compare the results of the DS-enabled scheme with two non-DS schemes, namely a fair bandwidth allocation scheme and a bandwidth contention scheme. The DS scheme outperforms the other two non-DS s...

Unmanned aerial vehicle-aided cooperative regenerative relaying network under various environments

International Journal of Electrical and Computer Engineering (IJECE), 2021

This paper studies a cooperative relay network that comprises an unmanned aerial vehicle (UAV) enabling amplify-and-forward (AF) and power splitting (PS) based energy harvesting. The considered system can be constructed in various environments such as suburban, urban, dense urban, and high-rise urban where the air-to-ground channels are model by a mixture of Rayleigh and Nakagami-m fading. Then, outage probability and ergodic capacity are provided under different environment-based parameters. Optimal PS ratios are also provided under normal and high transmit power regimes. Finally, the accuracy of the analytical results is validated through Monte Carlo methods.

Mobile Network-Connected Drones: Field Trials, Simulations, and Design Insights

IEEE Vehicular Technology Magazine, 2019

Drones are becoming increasingly used in a wide variety of industries and services and are delivering profound socioeconomic benefits. Technology needs to be in place to ensure safe operation and management of the growing fleet of drones. Mobile networks have connected tens of billions of devices on the ground in the past decades and are now ready to connect the drones flying in the sky. In this article, we share some of our findings in cellular connectivity for low altitude drones. We first present and analyze field measurement data collected during drone flights in a commercial Long-Term Evolution (LTE) network. We then present simulation results to shed light on the performance of a network when it is serving many drones simultaneously over a wide area. The results, analysis, and design insights presented in this article help enhance the understanding of the applicability and performance of providing mobile connectivity to low altitude drones.

Holes-in-the-Sky: A field study on cellular-connected UAS

2017 International Conference on Unmanned Aircraft Systems (ICUAS), 2017

Small unmanned aerial systems (UAS) require constant, safety-critical connectivity for telemetry, command-andcontrol, and collision avoidance. Today, dedicated, short-range pilot-to-aircraft links provide this connectivity for UAS operation. For UAS operating in fleets and beyond line-of-sight, a robust multi-transmitter network to provide connectivity over a wide area will be needed. However, networks that could serve this purpose, such as the ubiquitous broadband cellular networks, were planned and deployed for terminals on the ground. Hardening multi-transmitter networks for aerial use remains an open problem. In this paper, we demonstrate through field measurement that a typical cellular deployment could result in low-coverage areas for UAS-what we call the "hole-in-the-sky" phenomenon. Furthermore, many of the propagation models and assumptions commonly used in terrestrial network planning fail to accurately predict aerial signal strength. From first principles, we identify and model the predominant contributors to path loss, and form a combined propagation model that more accurately reflects reality for the tested scenarios. Motivated by this study, we identify a new research direction towards avoiding holes-in-the-sky during flight.

Performance Analysis of UAV‐Enabled Disaster Recovery Networks

2021

In this paper, we develop a comprehensive statistical framework to characterize and model large-scale unmanned aerial vehicle-enabled post-disaster recovery cellular networks. In the case of natural or man-made disasters, the cellular network is vulnerable to destruction resulting in coverage voids or coverage holes. Drone-based small cellular networks (DSCNs) can be rapidly deployed to fill such coverage voids. Due to capacity and back-hauling limitations on drone small cells (DSCs), each coverage hole requires a multitude of DSCs to meet the shortfall coverage at a desired quality-of-service. Moreover, ground users also tend to cluster in hot-spots in a post-disaster scenario. Motivated by this fact, we consider the clustered deployment of DSCs around the site of a destroyed BS. Joint consideration partially operating BSs and deployed DSCs yields a unique topology for such public safety networks. Borrowing tools from stochastic geometry, we develop a statistical framework to quantify the down-link performance of a DSCN. Our proposed clustering mechanism extends the traditional Matern and Thomas cluster processes to a more general case, where cluster size is dependent upon the size of the coverage hole. We then employ the newly developed framework to find closed-form expressions (later verified by Monte-Carlo simulations) to quantify the coverage probability, area spectral efficiency, and the energy efficiency for the down-link mobile user. Finally, we explore several design parameters (for both of the adopted cluster processes) that address optimal deployment of the network (i.e., number of drones per cluster, drone altitudes, and transmit power ratio between the traditional surviving base stations and the drone base stations). INDEX TERMS Drones, stochastic geometry, unmanned aerial vehicles, coverage probability, Poisson cluster processes.

Deployment of Drone-Based Small Cells for Public Safety Communication System

IEEE Systems Journal, 2020

In the event of a natural disaster, communications infrastructure plays an important role in organizing effective rescue services. However, the infrastructure-based communications are often affected during severe disaster events such as earthquakes, landslides, floods, and storm surges. Addressing this issue, the paper proposes a novel drone based cellular infrastructure to revive necessary communications for out-of-coverage User Equipment (UE) who is in the disaster area. In particular, a matching game algorithm is proposed using one-to-many approach wherein several Drone Small Cells (DSCs) are deployed to match different UEs to reach a stable connection with optimal throughput. In addition, a Medium Access Control (MAC) framework is then developed to optimize emergency and high priority communications initiated from the rescue workers and vulnerable individuals. The simulation results show that the throughput for the outof-coverage UEs are significantly improved when the DSCs are deployed in public safety network while the channel access delay is also notably reduced for emergency communications within the affected areas.