Design of cellular, satellite, and integrated systems for 5G and beyond

5G AgiLe and fLexible integration of SaTellite And cellulaR (5G-ALLSTAR) is a Korea-Europe (KR-EU) collaborative project for developing multi-connectivity (MC) technologies that integrate cellular and satellite networks to provide seamless, reliable, and ubiquitous broadband communication services and improve service continuity for 5G and beyond. The main scope of this project entails the prototype development of a millimeter-wave 5G New Radio (NR)-based cellular system, an investigation of the feasibility of an NR-based satellite system and its integration with cellular systems, and a study of spectrum sharing and interference management techniques for MC. This article reviews recent research activities and presents preliminary results and a plan for the proof of concept (PoC) of three representative use cases (UCs) and one joint KR-EU UC. The feasibility of each UC and superiority of the developed technologies will be validated with key performance indicators using corresponding PoC platforms. The final achievements of the project are expected to eventually contribute to the technical evolution of 5G, which will pave the road for next-generation communications

Learning and Reasoning Strategies for User Association in Ultra-dense Small Cell Vehicular Networks

Recent vehicular ad hoc networks research has been focusing on providing intelligent transportation services by employing information and communication technologies on road transport. It has been understood that advanced demands such as reliable connectivity, high user throughput, and ultra-low latency required by these services cannot be met using traditional communication technologies. Consequently, this thesis reports on the application of artificial intelligence to user association as a technology enabler in ultra-dense small cell vehicular networks. In particular, the work focuses on mitigating mobility-related concerns and networking issues at different mobility levels by employing diverse heuristic as well as reinforcement learning (RL) methods. Firstly, driven by rapid fluctuations in the network topology and the radio environment, a conventional, three-step sequence user association policy is designed to highlight and explore the impact of vehicle speed and different performance indicators on network quality of service (QoS) and user experience. Secondly, inspired by control-theoretic models and dynamic programming, a real-time controlled feedback user association approach is proposed. The algorithm adapts to the changing vehicular environment by employing derived network performance information as a heuristic, resulting in improved network performance. Thirdly, a sequence of novel RL based user association algorithms are developed that employ variable learning rate, variable rewards function and adaptation of the control feedback framework to improve the initial and steady-state learning performance. Furthermore, to accelerate the learning process and enhance the adaptability and robustness of the developed RL algorithms, heuristically accelerated RL and case-based transfer learning methods are employed. A comprehensive, two-tier, event-based, system level simulator which is an integration of a dynamic vehicular network, a highway, and an ultra-dense small cell network is developed. The model has enabled the analysis of user mobility effects on the network performance across different mobility levels as well as served as a firm foundation for the evaluation of the empirical properties of the investigated approaches

A Survey on 5G Usage Scenarios and Traffic Models

The fifth-generation mobile initiative, 5G, is a tremendous and collective effort to specify, standardize, design, manufacture, and deploy the next cellular network generation. 5G networks will support demanding services such as enhanced Mobile Broadband, Ultra-Reliable and Low Latency Communications and massive Machine-Type Communications, which will require data rates of tens of Gbps, latencies of few milliseconds and connection densities of millions of devices per square kilometer. This survey presents the most significant use cases expected for 5G including their corresponding scenarios and traffic models. First, the paper analyzes the characteristics and requirements for 5G communications, considering aspects such as traffic volume, network deployments, and main performance targets. Secondly, emphasizing the definition of performance evaluation criteria for 5G technologies, the paper reviews related proposals from principal standards development organizations and industry alliances. Finally, well-defined and significant 5G use cases are provided. As a result, these guidelines will help and ease the performance evaluation of current and future 5G innovations, as well as the dimensioning of 5G future deployments.This work is partially funded by the Spanish Ministry of Economy and Competitiveness (project TEC2016-76795-C6-4-R)H2020 research and innovation project 5G-CLARITY (Grant No. 871428)Andalusian Knowledge Agency (project A-TIC-241-UGR18)

Mobility management in 5G for high-speed trains

High-speed trains (HST) are nowadays more present in our lives currently, some of them can reach speeds up to 500 km/h and futuristic concepts such as hyperloop tunnels could make trains travel at speeds up to 1000 km/h. Dealing with such high speeds arises many communication problems, for example, in mobility management, with many handovers or high Doppler frequency shifts. You might be thinking how it is possible to provide a good QoS to the users inside the train, when traveling at such elevated velocities. In the thesis, we rely on the development of 5G New Radio and the benefits associated, such as a new handover protocol introduced by 3GPP called conditional handover (CHO). By simulating with Simu5G a HST scenario we have proved that CHO can provide a better service to the users by improving the SINR levels and being more efficient than common handover.Los trenes de alta velocidad están cada vez más presentes en nuestro día a día, algunos ya alcanzan velocidades de 500 km/h, mientras que otros conceptos futuristas como los túneles hyperloop podrían hacer que alcanzaran velocidades de hasta 1000 km/h. En el ámbito de las telecomunicaciones, trabajar a tan altas velocidades conlleva algunos problemas, como por ejemplo un elevado número de handovers. Seguramente, os estéis preguntando cómo es posible establecer un servicio que cumpla unos mínimos de calidad para el usuario, cuando este viaja a tan altas velocidades. Para ello, nos hemos apoyado en la tecnología 5G i un nuevo concepto de handover llamado conditional handover (CHO), introducido por el 3GPP. A través del simulador Simu5G, hemos conseguido demostrar que el CHO no solo es un protocolo más eficiente, sino que además conlleva una mejora en los niveles de SINR, en condiciones parecidas a las de un tren de alta velocidad.Els trens d'alta velocitat estan cada vegada més presents en el nostre dia a dia, alguns ja son capaços d'arribar a velocitats pròximes als 500 km/h, mentre que altres conceptes futuristes com els túnels hyperloop podrien fer que els trens arribessin a velocitats de 1000 km/h. En l'àmbit de les comunicacions, treballar amb velocitats tan elevades comporta alguns problemes, com per exemple un ampli número de handovers. Segurament, estareu pensant com es possible establir un servei que compleixi uns mínims de qualitat de cara a l'usuari, al estar treballant amb velocitats tant elevades. Per fer-ho ens hem recolzat en la tecnologia 5G i un nou concepte de handover presentat pel 3GPP, el conditional handover (CHO). Simulant a través de Simu5G un escenari similar al d'un tren d'alta velocitat, hem pogut demostrar que el CHO no es només un protocol més eficient que el handover normal, sinó que a més a més millora els nivells de SINR

On alleviating cell overload in vehicular scenarios

Fifth Generation (5G) networks will support countless new applications and new business models. One of the 5G paradigms is network slicing, which enables the integration of multiple logical networks each one tailored to the requirements of the different services that can be provided by both network operators and vertical industries. One of the services where 5G is expected to have a greatest impact is vehicular-to-everything (V2X) communications, which will have their stringent latency requirements now met. However, the mobility associated to vehicles can lead to cell overload compromising the required quality of service (QoS). To address this problem, in this paper we propose and evaluate the performance of three network overload alleviation techniques to control network congestion provoked by traffic jams using realistic vehicular traces in a network slicing environment. Firstly, we describe the architecture supporting V2X communications. Secondly, the network congestion control approaches are explained. Finally, after providing a complete description of the considered scenario, results will be detailed, showing that the network overload appearing during rush hour can be significantly reduced.This research was supported by the Spanish Centre for the Development of Industrial Technology (CDTI) and the Ministry of Economy, Industry and Competitiveness under grant/project CER-20191015 / Open, Virtualized Technology Demonstrators for Smart Networks (Open-VERSO).Peer ReviewedPostprint (author's final draft