Evaluación del rendimiento de la red 5G con diferentes implementaciones de sistemas de antenas distribuidas en mmW para zonas de alto tráfico en interiores

[ES] En la banda de mmW donde la cobertura es limitada, la implementación de cada transmisor exactamente donde se necesita se vuelve más crítica que nunca. Además, el número de dispositivos que se implementarán es mucho mayor que en frecuencias más bajas. En este marco, este trabajo final de grado tiene como objetivo evaluar cuáles son las mejores distribuciones de antenas de acuerdo con los requisitos de la red en banda mmW y considerando la simplicidad en la implementación práctica.[EN] In the mmW band where coverage is limited, deploying each transmitter exactly where it is needed becomes more critical than ever. In addition, the number of devices to be deployed is much higher than at lower frequencies. In this framework, this project aims to evaluate which are the best antenna distributions according to the requirements of the mmW network and considering the simplicity in practical deployment.Antón Ruiz, A. (2020). Evaluación del rendimiento de la red 5G con diferentes implementaciones de sistemas de antenas distribuidas en mmW para zonas de alto tráfico en interiores. http://hdl.handle.net/10251/152387TFG

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

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

Contextual Beamforming: Exploiting Location and AI for Enhanced Wireless Telecommunication Performance

The pervasive nature of wireless telecommunication has made it the foundation for mainstream technologies like automation, smart vehicles, virtual reality, and unmanned aerial vehicles. As these technologies experience widespread adoption in our daily lives, ensuring the reliable performance of cellular networks in mobile scenarios has become a paramount challenge. Beamforming, an integral component of modern mobile networks, enables spatial selectivity and improves network quality. However, many beamforming techniques are iterative, introducing unwanted latency to the system. In recent times, there has been a growing interest in leveraging mobile users' location information to expedite beamforming processes. This paper explores the concept of contextual beamforming, discussing its advantages, disadvantages and implications. Notably, the study presents an impressive 53% improvement in signal-to-noise ratio (SNR) by implementing the adaptive beamforming (MRT) algorithm compared to scenarios without beamforming. It further elucidates how MRT contributes to contextual beamforming. The importance of localization in implementing contextual beamforming is also examined. Additionally, the paper delves into the use of artificial intelligence schemes, including machine learning and deep learning, in implementing contextual beamforming techniques that leverage user location information. Based on the comprehensive review, the results suggest that the combination of MRT and Zero forcing (ZF) techniques, alongside deep neural networks (DNN) employing Bayesian Optimization (BO), represents the most promising approach for contextual beamforming. Furthermore, the study discusses the future potential of programmable switches, such as Tofino, in enabling location-aware beamforming

Analysis of TCP performance for LTE-5G Millimeter Wave Dual Connectivity

The goal of this work is the analysis of the performance of the transport control protocol (TCP) in a Dual connectivity (DC) system, where both LTE and 5G millimeter wave (mmWave) were used in the radio access network, while a single user travels across the scenario. Since the user is moving, the interaction between the mmWave base stations (BSs) must be very efficient to avoid congestion events. This makes the analysis of DC very important. Simulation models based on open-source software frameworks were used to evaluate the performance of Dual connectivity for a 5G non-standalone (NSA) solution, where all the 5G base station traffic goes through the LTE base station. The scenarios proposed were defined in terms of non-line-of-sight/line-of-sight (NLOS/LOS) scenario, medium/high traffic, which are used to evaluate different TCP congestion control algorithms. The performance was then evaluated in terms of goodput, packet delivery ratio, standard deviation of bytes in-flight, and round-trip time. Simulation results showed that the number of bytes in-flight grows with high rates and large latencies caused by inter-BS communication. The mmWave medium is very sensitive to channel conditions specially in the middle point between mmWave BSs causing ping-pong effect during a handover (HO). At the beginning of the simulation some nodes overflow due to the aggressive slow start mechanisms, which turn to be very problematic for high traffic rates. In that sense, TCP Cubic proves to be a much reliable congestion control algorithm since it implements a hybrid slow start method

View on 5G Architecture: Version 2.0

The 5G Architecture Working Group as part of the 5GPPP Initiative is looking at capturing novel trends and key technological enablers for the realization of the 5G architecture. It also targets at presenting in a harmonized way the architectural concepts developed in various projects and initiatives (not limited to 5GPPP projects only) so as to provide a consolidated view on the technical directions for the architecture design in the 5G era. The first version of the white paper was released in July 2016, which captured novel trends and key technological enablers for the realization of the 5G architecture vision along with harmonized architectural concepts from 5GPPP Phase 1 projects and initiatives. Capitalizing on the architectural vision and framework set by the first version of the white paper, this Version 2.0 of the white paper presents the latest findings and analyses with a particular focus on the concept evaluations, and accordingly it presents the consolidated overall architecture design

The design, simulation, and pattern synthesis of novel reflectarrays

The main focus of this thesis is on the development of both a comprehensive understanding and a thorough computational routine of the reflectarray metasurfaces designs, with focuses on a liquid crystal-based reconfigurable reflectarray metasurface and on the phase-retrieval/optimisation techniques for reflectarray-based pattern synthesis. A dielectric-based polarisation converting reflectarray metasurface is also presented, with the advantage of having a thinner profile over the traditional quartz-based half-wave plates. In the introductory sections, a thorough review of the state-of-the-art metasurfaces is presented, with a focus on applications to high-frequency wireless communications, as the motivation of this PhD is on the development of technologies that would facilitate the wireless communication challenges for the 5G-and-beyond frequency spectrum. In this section, a review of array antennas, including phased arrays, reflectarrays, transmitarrays, as well as metasurfaces utilising Mie-resonance, plasmonic resonance, geometric phase (Pancharatnam-Berry phase) and photoconductive material is presented. The following chapter on the theoretical background ensures the understanding of the fundamental mechanisms that will be applied to the study of reflectarray metasurfaces and optimisation routines. The high-frequency propagation associated with beyond-5G wireless communications brings many challenges to the current standards: some of the biggest problems are the much greater path loss and heavy non-line-of-sight signal attenuation. Traditionally, this has been dealt with in phased arrays. However, in the introduction part of this thesis, I show that this becomes impractical due to the requirements of enormous array sizes and expensive high-frequency phase shifters. Therefore, in our research, we have focused on reconfigurable reflectarrays as an intermediate solution to alleviate the tough propagation challenges faced by beyond-5G wireless communications. The reconfigurable reflectarray can either be designed to reflect off from a nearby mobile cell site to enhance the signal strength for non-line-of-sight areas, or it can include an integrated source to function independently, reducing the losses associated with power amplifiers and complex circuitries associated with the enormous array sizes. This thesis aims to produce a high-frequency tailored reconfigurable reflectarray design, which combines the conceptual advantages from state of-the-art lumped-element-based and liquid crystal-based reflectarrays. As shown in the literature review section, most recent researches on lumpedelement- based reconfigurable reflectarrays are designed for the sub 40 GHz frequencies; with higher frequencies, the intrinsic losses associated with lumped-elements such as PIN diodes make them unsuitable choices. On the other hand, liquid crystals have been used as a tunable material for different radio-frequency applications; however, most state-of-the-art designs of liquid crystal-based reflectarrays do not incorporate individual biasing control for maximum beam-control. There are also challenges faced with individually-biased reconfigurable reflectarrays. Traditionally, phased arrays can perform single beam-scanning or multiple beam-scanning with the control of multiple sub-arrays. We intend to achieve more complex beam-functionalities (such as vortex, null, and magnitude-specific beams) within the domain of manipulating one individual array. This is already possible with optimisation algorithms such as the genetic algorithm. However, traditional optimisers such as the genetic algorithm and particle swarm optimisation are far too slow to be implemented in an “online” mode, where the algorithm runs onboard the reflectarray to give low-latency solutions. The “online” optimisation mode would be very beneficial as it would reduce the channel occupation from the transmission of configuration information and thus increase channel capacity. In this thesis, I aim to develop an individually biased liquid crystal-based reconfigurable reflectarray for >100 GHz frequencies. I also aim to develop an algorithm that is sufficiently quick to have the potential to be practically utilised as an onboard pattern synthesis optimisation method. Additionally, using the same design principles, I have designed an all-dielectric-based reflectarray metasurface that acts as a polarisation-converting quarter-wave plate, which is much thinner than traditional quartz-based quarter-wave plates. In the Research Results and Publications chapter, a complete procedure for the design of LC-based reconfigurable and dielectric-based nonreconfigurable reflectarray metasurfaces is presented, where much of the content comes from the author’s own publications[52, 78, 50, 51]. This thesis provides details on the computational tools/programs used, cross-platform routines development with CST Studio Suite, MATLAB and VBA, and the pattern synthesis algorithm, whereby a genetic algorithm is employed for the global optimisation, and an improved Gerchberg-Saxton algorithm is developed and adapted to the application of faster local optimisation for the pattern synthesis. For the all-dielectric reflectarray metasurface, the further functionality of polarisation conversion (linear to circular and circular to linear) is demonstrated on top of the beam-manipulation capabilities of the reflectarrays. The reflectarray metasurfaces can be designed to beamform, beamsteer, beamsplit/multibeam, as well as achieve novel beam profiles such as the vortex profile. Originally, the idea was to completely focus on the liquid crystal-based study and to develop a down-scaled 28 GHz proof-of-concept, for which partial work had already begun (the simulation, optimisation and initial planning on the construction with collaborators from other departments); however, due to the pandemic and numerous other uncontrollable factors, this was later discarded and replaced by remaining on and extending upon the computational studies, to further understand and improve the pattern synthesis algorithms and the other types of phase-change metasurfaces

Resource management in future mobile networks: from millimetre-wave backhauls to airborne access networks

The next generation of mobile networks will connect vast numbers of devices and support services with diverse requirements. Enabling technologies such as millimetre-wave (mm-wave) backhauling and network slicing allow for increased wireless capacities and logical partitioning of physical deployments, yet introduce a number of challenges. These include among others the precise and rapid allocation of network resources among applications, elucidating the interactions between new mobile networking technology and widely used protocols, and the agile control of mobile infrastructure, to provide users with reliable wireless connectivity in extreme scenarios. This thesis presents several original contributions that address these challenges. In particular, I will first describe the design and evaluation of an airtime allocation and scheduling mechanism devised specifically for mm-wave backhauls, explicitly addressing inter-flow fairness and capturing the unique characteristics of mm-wave communications. Simulation results will demonstrate 5x throughput gains and a 5-fold improvement in fairness over recent mm-wave scheduling solutions. Second, I will introduce a utility optimisation framework targeting virtually sliced mm-wave backhauls that are shared by a number of applications with distinct requirements. Based on this framework, I will present a deep learning solution that can be trained within minutes, following which it computes rate allocations that match those obtained with state-of-the-art global optimisation algorithms. The proposed solution outperforms a baseline greedy approach by up to 62%, in terms of network utility, while running orders of magnitude faster. Third, the thesis investigates the behaviour of the Transport Control Protocol (TCP) in Long-Term Evolution (LTE) networks and discusses the implications of employing Radio Link Control (RLC) acknowledgements under different link qualities, on the performance of transport protocols. Fourth, I will introduce a reinforcement learning approach to optimising the performance of airborne cellular networks serving users in emergency settings, demonstrating rapid convergence (approx. 2.5 hours on a desktop machine) and a 5dB improvement of the median Signal-to-Noise-plus-Interference-Ratio (SINR) perceived by users, over a heuristic based benchmark solution. Finally, the thesis discusses promising future research directions that follow from the results obtained throughout this PhD project

Study, Measurements and Characterisation of a 5G system using a Mobile Network Operator Testbed

The goals for 5G are aggressive. It promises to deliver enhanced end-user experience by offering new applications and services through gigabit speeds, and significantly improved performance and reliability. The enhanced mobile broadband (eMBB) 5G use case, for instance, targets peak data rates as high as 20 Gbps in the downlink (DL) and 10 Gbps in the uplink (UL). While there are different ways to improve data rates, spectrum is at the core of enabling higher mobile broadband data rates. 5G New Radio (NR) specifies new frequency bands below 6 GHz and also extends into mmWave frequencies where more contiguous bandwidth is available for sending lots of data. However, at mmWave frequencies, signals are more susceptible to impairments. Hence, extra consideration is needed to determine test approaches that provide the precision required to accurately evaluate 5G components and devices. Therefore, the aim of the thesis is to provide a deep dive into 5G technology, explore its testing and validation, and thereafter present the OTE (Hellenic Telecommunications Organisation) 5G testbed, including measurement results obtained and its characterisation based on key performance indicators (KPIs)