3,912 research outputs found

    Experimental evaluation of a software defined radio-based prototype for a disaster response cellular network

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    In post disaster situations it is vital to restore voice and data communication services quickly. Currently, portable wireless systems are used as a temporary solution. However, these solutions have a lengthy setup, limited coverage, and typically require the use of expensive satellite backhaul. Solutions based on cognitive radio mesh networks have been proposed, to exploit self-configuration and spectrum agility. To evaluate their potential, we build a software-radio-based prototype for a multi-cell network that uses an IEEE 802.11's unlicensed wireless communication band for backhaul, and an open-source GSM stack for access. The prototype provides voice communication services. We evaluate the prototype in an open environment. We demonstrate that under the right conditions, the system can support large numbers of simultaneous calls with acceptable quality. However, when the unlicensed band is heavily used, call quality quickly degrades because of interference on the backhaul link. We conclude that in order to provide acceptable quality of service it is desirable to exploit idle licensed spectrum for backhaul communication between base stations

    A Survey on Cellular-connected UAVs: Design Challenges, Enabling 5G/B5G Innovations, and Experimental Advancements

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    As an emerging field of aerial robotics, Unmanned Aerial Vehicles (UAVs) have gained significant research interest within the wireless networking research community. As soon as national legislations allow UAVs to fly autonomously, we will see swarms of UAV populating the sky of our smart cities to accomplish different missions: parcel delivery, infrastructure monitoring, event filming, surveillance, tracking, etc. The UAV ecosystem can benefit from existing 5G/B5G cellular networks, which can be exploited in different ways to enhance UAV communications. Because of the inherent characteristics of UAV pertaining to flexible mobility in 3D space, autonomous operation and intelligent placement, these smart devices cater to wide range of wireless applications and use cases. This work aims at presenting an in-depth exploration of integration synergies between 5G/B5G cellular systems and UAV technology, where the UAV is integrated as a new aerial User Equipment (UE) to existing cellular networks. In this integration, the UAVs perform the role of flying users within cellular coverage, thus they are termed as cellular-connected UAVs (a.k.a. UAV-UE, drone-UE, 5G-connected drone, or aerial user). The main focus of this work is to present an extensive study of integration challenges along with key 5G/B5G technological innovations and ongoing efforts in design prototyping and field trials corroborating cellular-connected UAVs. This study highlights recent progress updates with respect to 3GPP standardization and emphasizes socio-economic concerns that must be accounted before successful adoption of this promising technology. Various open problems paving the path to future research opportunities are also discussed.Comment: 30 pages, 18 figures, 9 tables, 102 references, journal submissio

    Planning UAV Activities for Efficient User Coverage in Disaster Areas

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    Climate changes brought about by global warming as well as man-made environmental changes are often the cause of sever natural disasters. ICT, which is itself responsible for global warming due to its high carbon footprint, can play a role in alleviating the consequences of such hazards by providing reliable, resilient means of communication during a disaster crisis. In this paper, we explore the provision of wireless coverage through UAVs (Unmanned Aerial Vehicles) to complement, or replace, the traditional communication infrastructure. The use of UAVs is indeed crucial in emergency scenarios, as they allow for the quick and easy deployment of micro and pico cellular base stations where needed. We characterize the movements of UAVs and define an optimization problem to determine the best UAV coverage that maximizes the user throughput, while maintaining fairness across the different parts of the geographical area that has been affected by the disaster. To evaluate our strategy, we simulate a flooding in San Francisco and the car traffic resulting from people seeking safety on higher ground

    An Intent-Based Reasoning System for Automatic Generation of Drone Missions for Public Protection and Disaster Relief

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    The utilization of drones for search and rescue operations has become more prevalent over the years. Drones can provide an aerial perspective which can aid first responders in gaining an overview of a situation. Autonomous drones can automate search and rescue operations by removing the human pilot, which can increase efficiency and lower costs. The increased development of machine learning models and techniques has paved the way for intent-based reasoning systems that can understand users' intent. This can allow users to control autonomous drones by expressing their intent. Which can be utilized for search and rescue operations. However, machine learning models require vast computational power and data storage. In addition, autonomous drones have high-performance requirements. The development of 5G can provide the infrastructure required to meet the stringent performance requirements of machine learning models and autonomous drones. By leveraging the advanced features of 5G, such as network slicing, high-speed communication, and low latency, it provides the infrastructure that supports the use of machine learning models in coordination with drones. This thesis proposes a system prototype that can generate drone missions based on user intent which can be used for rescue operations. The system utilizes a large language model and automatic speech recognition model to capture the intent of the user and generate drone missions that integrate with a 4G-enabled drone. The evaluation of the system reveals that the system can reliably capture the user's intent with simple commands, but struggles with more complex commands. The prototype demonstrates that intent-based reasoning systems for controlling autonomous drones using 5G technology can aid first responders during PPDR missions

    Modeling the Use of an Airborne Platform for Cellular Communications Following Disruptions

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    In the wake of a disaster, infrastructure can be severely damaged, hampering telecommunications. An Airborne Communications Network (ACN) allows for rapid and accurate information exchange that is essential for the disaster response period. Access to information for survivors is the start of returning to self-sufficiency, regaining dignity, and maintaining hope. Real-world testing has proven that such a system can be built, leading to possible future expansion of features and functionality of an emergency communications system. Currently, there are no airborne civilian communications systems designed to meet the demands of the public following a natural disaster. A system allowing even a limited amount of communications post-disaster is a great improvement on the current situation, where telecommunications are frequently not available. It is technically feasible to use an airborne, wireless, cellular system quickly deployable to disaster areas and configured to restore some of the functions of damaged terrestrial telecommunications networks. The system requirements were presented, leading to the next stage of the planned research, where a range of possible solutions were examined. The best solution was selected based on the earlier, predefined criteria. The system was modeled, and a test ii system built. The system was tested and redesigned when necessary, to meet the requirements. The research has shown how the combination of technology, especially the recent miniaturizations and move to open source software for cellular network components can allow sophisticated cellular networks to be implemented. The ACN system proposed could enable connectivity and reduce the communications problems that were experienced following Hurricane Sandy and Katrina. Experience with both natural and man-made disasters highlights the fact that communications are useful only to the extent that they are accessible and useable by the population

    Real-Time Implementation of Spectrum Sensing Techniques in Cognitive Radios

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    Wireless communication requirements of higher sampling frequencies and bandwidth are ever increasing. For this purpose, exploitation of underutilized spectrum bands was one the challenging research targets. Cognitive Radio (CR) is a promising solution to overcome the “limited bandwidth” issue. Software defined radio (SDR) is the enabler of CR. The aim of the thesis is to adopt the vacant TV channels for secondary users. Spectrum sensing prototype has been proposed to detect TV white space (TVWS). The prototype has been developed using Universal Software Radio Peripheral (USRP) and examined to sense TVWS in the real time world. The conducting analysis of obtained measurements showed the state of unoccupied spectrum bands in the UHF band ranges from 500 MHz to 698 MHz in the urban area ofWindsor, Ontario, Canada. Two different spectrum sensing techniques namely, the energy detector, and pilot-tone detector were employed to get the result with minimum computational complexity. Experiments show that the presence of incumbent users can be easily detected using the spectrum sensing techniques mentioned in the thesis. The experimental results have demonstrated the validity of the proposed prototyp

    Involuntary Signal-Based Grounding of Civilian Unmanned Aerial Systems (UAS) in Civilian Airspace

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    This thesis investigates the involuntary signal-based grounding of civilian unmanned aerial systems (UAS) in unauthorized air spaces. The technique proposed here will forcibly land unauthorized UAS in a given area in such a way that the UAS will not be harmed, and the pilot cannot stop the landing. The technique will not involuntarily ground authorized drones which will be determined prior to the landing. Unauthorized airspaces include military bases, university campuses, areas affected by a natural disaster, and stadiums for public events. This thesis proposes an early prototype of a hardware-based signal based involuntary grounding technique to handle the problem by immediately grounding unauthorized drones. Research in the development of UAS is in the direction of airspace integration. For the potential of airspace integration three communication protocols were evaluated: LoRa WAN, Bluetooth 5, and Frequency Shift Keying (FSK) for their long range capabilities. Of the three technologies, LoRa WAN transmitted the farthest, however the FSK module transmitted a comparable distance at a lower power. The power measurements were taken using existing modules, however, due to LoRa using a higher frequency than the FSK module this outcome was expected

    Internet of Things-aided Smart Grid: Technologies, Architectures, Applications, Prototypes, and Future Research Directions

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    Traditional power grids are being transformed into Smart Grids (SGs) to address the issues in existing power system due to uni-directional information flow, energy wastage, growing energy demand, reliability and security. SGs offer bi-directional energy flow between service providers and consumers, involving power generation, transmission, distribution and utilization systems. SGs employ various devices for the monitoring, analysis and control of the grid, deployed at power plants, distribution centers and in consumers' premises in a very large number. Hence, an SG requires connectivity, automation and the tracking of such devices. This is achieved with the help of Internet of Things (IoT). IoT helps SG systems to support various network functions throughout the generation, transmission, distribution and consumption of energy by incorporating IoT devices (such as sensors, actuators and smart meters), as well as by providing the connectivity, automation and tracking for such devices. In this paper, we provide a comprehensive survey on IoT-aided SG systems, which includes the existing architectures, applications and prototypes of IoT-aided SG systems. This survey also highlights the open issues, challenges and future research directions for IoT-aided SG systems
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