Modeling and Analysis of HetNets with mm-Wave Multi-RAT Small Cells Deployed Along Roads

We characterize a multi tier network with classical macro cells, and multi radio access technology (RAT) small cells, which are able to operate in microwave and millimeter-wave (mm-wave) bands. The small cells are assumed to be deployed along roads modeled as a Poisson line process. This characterization is more realistic as compared to the classical Poisson point processes typically used in literature. In this context, we derive the association and RAT selection probabilities of the typical user under various system parameters such as the small cell deployment density and mm-wave antenna gain, and with varying street densities. Finally, we calculate the signal to interference plus noise ratio (SINR) coverage probability for the typical user considering a tractable dominant interference based model for mm-wave interference. Our analysis reveals the need of deploying more small cells per street in cities with more streets to maintain coverage, and highlights that mm-wave RAT in small cells can help to improve the SINR performance of the users.Comment: A 7-page version is submitted to IEEE GLOBECOM 201

Context awareness and related challenges: A comprehensive evaluation study for a context-based RAT selection scheme towards 5G networks

Ο αποτελεσματικός σχεδιασμός των δικτύων είναι απαραίτητος για να αντιμετωπιστεί ο αυξανόμενος αριθμός των συνδρομητών κινητού διαδικτύου και των απαιτητικών υπηρεσιών δεδομένων, που ανταγωνίζονται για περιορισμένους ασύρματους πόρους. Επιπλέον, οι βασικές προκλήσεις για τα συνεχώς αναπτυσσόμενα δίκτυα LTE είναι η αύξηση των δυνατοτήτων των υφιστάμενων μηχανισμών, η μείωση της υπερβολικής σηματοδότησης (signaling) και η αξιοποίηση ενός αποτελεσματικού μηχανισμού επιλογής τεχνολογίας ασύρματης πρόσβασης (RAT). Υπάρχουν ποικίλες προτάσεις στην βιβλιογραφία σχετικά με αυτές τις προκλήσεις, μερικές από τις οποίες παρουσιάζονται εδώ. Ο σκοπός της εργασίας αυτής είναι να ερευνήσει τις τρέχουσες εξελίξεις στα δίκτυα LTE σχετικά με την ενσωμάτωση EPC και WiFi και την επίγνωση πλαισίου (context awareness) στην διαχείριση κινητικότητας, και να προτείνει τον αλγόριθμο COmpAsS, έναν μηχανισμό που χρησιμοποιεί ασαφή λογική (fuzzy logic) για να επιλέξει την πιο κατάλληλη τεχνολογία ασύρματης πρόσβασης για τα κινητά. Επιπλέον, έχουμε ποσοτικοποιήσει το κόστος σηματοδότησης του προτεινόμενου μηχανισμού σε σύνδεση με τις σημερινές προδιαγραφές του 3GPP και εκτελέσαμε μια ολοκληρωμένη ανάλυση. Τέλος, αξιολογήσαμε τον αλγόριθμο μέσω εκτεταμένων προσομοιώσεων σε ένα πολύπλοκο και ρεαλιστικό σενάριο χρήσης 5G, που απεικονίζονται τα σαφή πλεονεκτήματα της προσέγγισής μας όσον αφορά τη συχνότητα μεταπομπών (handover) και τις μετρήσεις βασικών QoS τιμών, όπως ρυθμός μετάδοσης και καθυστέρηση.Effective network planning is essential to cope with the increasing number of mobile internet subscribers and bandwidth-intensive services competing for limited wireless resources. Additionally, key challenges for the constantly growing LTE networks is increasing capabilities of current mechanisms, reduction of signaling overhead and the utilization of an effective Radio Access Technology (RAT) selection scheme. There have been various proposals in literature regarding these challenges, some of which are discussed here. The purpose of this work is to research the current advances in LTE networks regarding EPC - WiFi integration and context awareness in mobility management, and propose the COmpAsS algorithm, a mechanism using fuzzy logic to select the most suitable Radio Access Technology. Furthermore, we quantify the signaling overhead of the proposed mechanism by linking it to the current 3GPP specifications and performing a comprehensive analysis. Finally, we evaluate the novel scheme via extensive simulations in a complex and realistic 5G use case, illustrating the clear advantages of our approach in terms of handover frequency and key QoS metrics, i.e. the user-experienced throughput and delay

A Comprehensive Survey on Moving Networks

The unprecedented increase in the demand for mobile data, fuelled by new emerging applications such as HD video streaming and heightened online activities has caused massive strain on the existing cellular networks. As a solution, the 5G technology has been introduced to improve network performance through various innovative features such as mmWave spectrum and HetNets. In essence, HetNets include several small cells underlaid within macro-cell to serve densely populated regions. Recently, a mobile layer of HetNet has been under consideration by the researchers and is often referred to as moving networks. Moving networks comprise of mobile cells that are primarily introduced to improve QoS for commuting users inside public transport because the QoS is deteriorated due to vehicular penetration losses. Furthermore, the users inside fast moving public transport also exert excessive load on the core network due to large group handovers. To this end, mobile cells will play a crucial role in reducing overall handover count and will help in alleviating these problems by decoupling in-vehicle users from the core network. To date, remarkable research results have been achieved by the research community in addressing challenges linked to moving networks. However, to the best of our knowledge, a discussion on moving networks in a holistic way is missing in the current literature. To fill the gap, in this paper, we comprehensively survey moving networks. We cover the technological aspects and their applications in the futuristic applications. We also discuss the use-cases and value additions that moving networks may bring to future cellular architecture and identify the challenges associated with them. Based on the identified challenges we discuss the future research directions.Comment: This survey has been submitted to IEEE Communications Surveys & Tutorial

A survey of machine learning applications to handover management in 5G and beyond

Handover (HO) is one of the key aspects of next-generation (NG) cellular communication networks that need to be properly managed since it poses multiple threats to quality-of-service (QoS) such as the reduction in the average throughput as well as service interruptions. With the introduction of new enablers for fifth-generation (5G) networks, such as millimetre wave (mm-wave) communications, network densification, Internet of things (IoT), etc., HO management is provisioned to be more challenging as the number of base stations (BSs) per unit area, and the number of connections has been dramatically rising. Considering the stringent requirements that have been newly released in the standards of 5G networks, the level of the challenge is multiplied. To this end, intelligent HO management schemes have been proposed and tested in the literature, paving the way for tackling these challenges more efficiently and effectively. In this survey, we aim at revealing the current status of cellular networks and discussing mobility and HO management in 5G alongside the general characteristics of 5G networks. We provide an extensive tutorial on HO management in 5G networks accompanied by a discussion on machine learning (ML) applications to HO management. A novel taxonomy in terms of the source of data to be utilized in training ML algorithms is produced, where two broad categories are considered; namely, visual data and network data. The state-of-the-art on ML-aided HO management in cellular networks under each category is extensively reviewed with the most recent studies, and the challenges, as well as future research directions, are detailed

Adaptive Network Densification with Small Cell Mobile Base Stations Carried by Vehicles

1noL'abstract è presente nell'allegato / the abstract is in the attachmentopen676. INGEGNERIA ELETTRICAnopartially_openembargoed_20211014Mohammadnia, Foroog

Energy and cost management in shared heterogeneous network deployments

During the recent years, a huge augmentation of the data traffic volume has been noticed, while a further steep increase is expected in the following years. As a result, questions have been raised over the years about the energy consumption needs of the wireless telecommunication networks, their carbon dioxide emissions and their operational expenses. Aiming at meeting the high traffic demands with flat energy consumption and flat incurred expenses, mobile network operators (MNOs) have opted to improve their position (i) by deploying heterogeneous networks (HetNets), which are consisted of macrocell base stations (MBSs) and small cell base stations (SBSs) and (ii) by sharing their infrastructure. However, questions could be raised about the extend to which HetNet densification is of aid. Given that network planning is executed according to high traffic load volumes, BS underutilisation during low-traffic hours cannot be neglected. Similarly, the aggregated energy needs of multiple SBSs equals the ones of an energy hungry MBS, having thus a respectable share of the net energy consumption. In this context, a set of research opportunities have been identified. This thesis provides contribution toward the achievement of a greener and more cost efficient operation of HetNet deployments, where multiple stakeholders develop their activity and where energy support can have the form of various alternate schemes, including renewable energy (RE) sources. Depending on the network energy support, i.e., whether RE sources are used in the network or not, the main body of this thesis is divided in two research directions. The first part of the thesis uses the technology of switching off strategies in order to explore their efficiency in terms of both energy and costs in a HetNet. The HetNet is assumed to be a roaming-based cooperative activity of multiple MNOs that is powered exclusively by grid energy. A switching off and a cost allocation scheme are proposed, using as criteria the BS type, the BS load and the roaming cost for traffic offloading. The performance of the proposed schemes is evaluated with respect to energy efficiency, cost savings and fairness, using computer-based simulations. The second part of the thesis explores energy and cost management issues in energy harvesting (EH) HetNet deployments where EH-BSs use an EH system (EHS), an energy storage system (ESS) and the smart grid (SG) as energy procurement sources. The EH-HetNet is assumed a two-tier network deployment of EH-MBSs that are passively shared among an MNO set and EH-SBSs that are provided to MNOs by an infrastructure provider. Taking into consideration the infrastructure location and the variety of stakeholders involved in the network deployment, approaches of RE exchange (REE) are proposed as a cooperative RE sharing for the shared EH-MBSs, based on bankruptcy theory, and a non-cooperative, aggregator-assisted RE trading, based on double auctions, for the EH-SBSs. The performance of the proposed schemes is evaluated in terms of the hours of independence of the studied system from the SG, the fairness regulated by the provided solution and the economical payoffs extracted for the stakeholdersDurante los últimos años, se ha notado un aumento enorme del volumen de tráfico de datos, mientras que se espera un nuevo aumento en los próximos años. Como resultado, se han planteado preguntas sobre las necesidades de consumo de energía de las redes inalámbricas de telecomunicaciones, sus emisiones de dióxido de carbono y sus gastos operativos. Con el objetivo de satisfacer las altas demandas de tráfico con consumo de energía constante y con gastos incurridos constantes, además de utilizar soluciones basadas en la nube, los operadores de redes móviles (MNOs) han optado por mejorar su posición (i) desplegando redes heterogéneas (HetNets), que consisten en estaciones base de macro-células (MBSs) y estaciones base de células pequeñas (SBSs), y (ii) compartiendo su infraestructura. Sin embargo, podrían plantearse preguntas sobre hasta qué punto la densificación de una HetNet es de ayuda. Dado que la planificación de la red se ejecuta de acuerdo con los volúmenes de carga de tráfico más elevados, no se puede descuidar la subutilización de las estaciones base (BS) durante las horas de poco tráfico. De manera similar, las necesidades de energía agregadas de múltiples SBSs son iguales a las de una MBS que consume mucha energía, teniendo así una parte respetable del consumo neto de energía. En este contexto, se ha identificado un conjunto de oportunidades de investigación. Esta tesis contribuye al logro de una operación más ecológica y rentable de las implementaciones de HetNet, donde múltiples partes interesadas desarrollan su actividad y donde el apoyo energético puede tener la forma de varios esquemas alternativos, incluidas las fuentes de energía renovables (RE). Dependiendo del soporte de energía de red, es decir, si las fuentes de RE se usan en la red o no, el cuerpo principal de esta tesis se divide en dos direcciones de investigación. La primera parte de la tesis utiliza la tecnología de las estrategias de apagado con el objetivo de explorar su eficiencia en términos de energía y gastos en una HetNet. Se asume que la HetNet es una actividad cooperativa basada en la itinerancia de múltiples MNO que se alimenta exclusivamente de energía de la red. Se propone un esquema de desconexión y de asignación de costes, que utiliza como criterios el tipo de BS, la carga de BS y el coste de la itinerancia para la descarga de tráfico. El rendimiento de los esquemas propuestos se evalúa con respecto a la eficiencia energética, el ahorro de costes y la equidad, usando simulaciones en computadora. La segunda parte de la tesis explora los problemas de gestión de energía y de costes en las implementaciones de HetNet donde las estaciones base recolectan energía usando un sistema EH (EHS), un sistema de almacenamiento de energía (ESS) y la red eléctrica inteligente (SG) como sistemas de adquisición de energía. Se asume que el EH-HetNet es una implementación de redes de dos niveles donde los EH-MBSs se comparten pasivamente entre un conjunto de MNOs y EH-SBSs se proporcionan a los MNOs de un proveedor de infraestructura. Teniendo en cuenta la ubicación de la infraestructura y la variedad de partes interesadas e involucradas en el despliegue de la red, se proponen enfoques de intercambio de RE (REE) como un intercambio cooperativo de RE para los EH-MBS compartidos, basado en la teoría de bancarrota, y un no cooperativo comercio de RE para los EH-SBSs, que es asistido por un agregador y basado en las subastas dobles. El rendimiento de los esquemas propuestos se evalúa en términos de las horas de independencia del sistema estudiado con respecto al SG, la imparcialidad regulada por la solución proporcionada y los beneficios económicos extraídos para las interesadas

Energy and cost management in shared heterogeneous network deployments

Pla de Doctorat industrial de la Generalitat de CatalunyaDuring the recent years, a huge augmentation of the data traffic volume has been noticed, while a further steep increase is expected in the following years. As a result, questions have been raised over the years about the energy consumption needs of the wireless telecommunication networks, their carbon dioxide emissions and their operational expenses. Aiming at meeting the high traffic demands with flat energy consumption and flat incurred expenses, mobile network operators (MNOs) have opted to improve their position (i) by deploying heterogeneous networks (HetNets), which are consisted of macrocell base stations (MBSs) and small cell base stations (SBSs) and (ii) by sharing their infrastructure. However, questions could be raised about the extend to which HetNet densification is of aid. Given that network planning is executed according to high traffic load volumes, BS underutilisation during low-traffic hours cannot be neglected. Similarly, the aggregated energy needs of multiple SBSs equals the ones of an energy hungry MBS, having thus a respectable share of the net energy consumption. In this context, a set of research opportunities have been identified. This thesis provides contribution toward the achievement of a greener and more cost efficient operation of HetNet deployments, where multiple stakeholders develop their activity and where energy support can have the form of various alternate schemes, including renewable energy (RE) sources. Depending on the network energy support, i.e., whether RE sources are used in the network or not, the main body of this thesis is divided in two research directions. The first part of the thesis uses the technology of switching off strategies in order to explore their efficiency in terms of both energy and costs in a HetNet. The HetNet is assumed to be a roaming-based cooperative activity of multiple MNOs that is powered exclusively by grid energy. A switching off and a cost allocation scheme are proposed, using as criteria the BS type, the BS load and the roaming cost for traffic offloading. The performance of the proposed schemes is evaluated with respect to energy efficiency, cost savings and fairness, using computer-based simulations. The second part of the thesis explores energy and cost management issues in energy harvesting (EH) HetNet deployments where EH-BSs use an EH system (EHS), an energy storage system (ESS) and the smart grid (SG) as energy procurement sources. The EH-HetNet is assumed a two-tier network deployment of EH-MBSs that are passively shared among an MNO set and EH-SBSs that are provided to MNOs by an infrastructure provider. Taking into consideration the infrastructure location and the variety of stakeholders involved in the network deployment, approaches of RE exchange (REE) are proposed as a cooperative RE sharing for the shared EH-MBSs, based on bankruptcy theory, and a non-cooperative, aggregator-assisted RE trading, based on double auctions, for the EH-SBSs. The performance of the proposed schemes is evaluated in terms of the hours of independence of the studied system from the SG, the fairness regulated by the provided solution and the economical payoffs extracted for the stakeholdersDurante los últimos años, se ha notado un aumento enorme del volumen de tráfico de datos, mientras que se espera un nuevo aumento en los próximos años. Como resultado, se han planteado preguntas sobre las necesidades de consumo de energía de las redes inalámbricas de telecomunicaciones, sus emisiones de dióxido de carbono y sus gastos operativos. Con el objetivo de satisfacer las altas demandas de tráfico con consumo de energía constante y con gastos incurridos constantes, además de utilizar soluciones basadas en la nube, los operadores de redes móviles (MNOs) han optado por mejorar su posición (i) desplegando redes heterogéneas (HetNets), que consisten en estaciones base de macro-células (MBSs) y estaciones base de células pequeñas (SBSs), y (ii) compartiendo su infraestructura. Sin embargo, podrían plantearse preguntas sobre hasta qué punto la densificación de una HetNet es de ayuda. Dado que la planificación de la red se ejecuta de acuerdo con los volúmenes de carga de tráfico más elevados, no se puede descuidar la subutilización de las estaciones base (BS) durante las horas de poco tráfico. De manera similar, las necesidades de energía agregadas de múltiples SBSs son iguales a las de una MBS que consume mucha energía, teniendo así una parte respetable del consumo neto de energía. En este contexto, se ha identificado un conjunto de oportunidades de investigación. Esta tesis contribuye al logro de una operación más ecológica y rentable de las implementaciones de HetNet, donde múltiples partes interesadas desarrollan su actividad y donde el apoyo energético puede tener la forma de varios esquemas alternativos, incluidas las fuentes de energía renovables (RE). Dependiendo del soporte de energía de red, es decir, si las fuentes de RE se usan en la red o no, el cuerpo principal de esta tesis se divide en dos direcciones de investigación. La primera parte de la tesis utiliza la tecnología de las estrategias de apagado con el objetivo de explorar su eficiencia en términos de energía y gastos en una HetNet. Se asume que la HetNet es una actividad cooperativa basada en la itinerancia de múltiples MNO que se alimenta exclusivamente de energía de la red. Se propone un esquema de desconexión y de asignación de costes, que utiliza como criterios el tipo de BS, la carga de BS y el coste de la itinerancia para la descarga de tráfico. El rendimiento de los esquemas propuestos se evalúa con respecto a la eficiencia energética, el ahorro de costes y la equidad, usando simulaciones en computadora. La segunda parte de la tesis explora los problemas de gestión de energía y de costes en las implementaciones de HetNet donde las estaciones base recolectan energía usando un sistema EH (EHS), un sistema de almacenamiento de energía (ESS) y la red eléctrica inteligente (SG) como sistemas de adquisición de energía. Se asume que el EH-HetNet es una implementación de redes de dos niveles donde los EH-MBSs se comparten pasivamente entre un conjunto de MNOs y EH-SBSs se proporcionan a los MNOs de un proveedor de infraestructura. Teniendo en cuenta la ubicación de la infraestructura y la variedad de partes interesadas e involucradas en el despliegue de la red, se proponen enfoques de intercambio de RE (REE) como un intercambio cooperativo de RE para los EH-MBS compartidos, basado en la teoría de bancarrota, y un no cooperativo comercio de RE para los EH-SBSs, que es asistido por un agregador y basado en las subastas dobles. El rendimiento de los esquemas propuestos se evalúa en términos de las horas de independencia del sistema estudiado con respecto al SG, la imparcialidad regulada por la solución proporcionada y los beneficios económicos extraídos para las interesadas.Postprint (published version

Improved handover decision scheme for 5g mm-wave communication: optimum base station selection using machine learning approach.

A Thesis Submitted in Partial Fulfillment of the Requirements for the Degree of Doctor of Philosophy in Information and Communication Science and Engineering of the Nelson Mandela African Institution of Science and TechnologyThe rapid growth in mobile and wireless devices has led to an exponential demand for data traf fic and exacerbated the burden on conventional wireless networks. Fifth generation (5G) and beyond networks are expected to not only accommodate this growth in data demand but also provide additional services beyond the capability of existing wireless networks, while main taining a high quality-of-experience (QoE) for users. The need for several orders of magnitude increase in system capacity has necessitated the use of millimetre wave (mm-wave) frequencies as well as the proliferation of low-power small cells overlaying the existing macro-cell layer. These approaches offer a potential increase in throughput in magnitudes of several gigabits per second and a reduction in transmission latency, but they also present new challenges. For exam ple, mm-wave frequencies have higher propagation losses and a limited coverage area, thereby escalating mobility challenges such as more frequent handovers (HOs). In addition, the ad vent of low-power small cells with smaller footprints also causes signal fluctuations across the network, resulting in repeated HOs (ping-pong) from one small cell (SC) to another. Therefore, efficient HO management is very critical in future cellular networks since frequent HOs pose multiple threats to the quality-of-service (QoS), such as a reduction in the system throughput as well as service interruptions, which results in a poor QoE for the user. How ever, HO management is a significant challenge in 5G networks due to the use of mm-wave frequencies which have much smaller footprints. To address these challenges, this work in vestigates the HO performance of 5G mm-wave networks and proposes a novel method for achieving seamless user mobility in dense networks. The proposed model is based on a double deep reinforcement learning (DDRL) algorithm. To test the performance of the model, a com parative study was made between the proposed approach and benchmark solutions, including a benchmark developed as part of this thesis. The evaluation metrics considered include system throughput, execution time, ping-pong, and the scalability of the solutions. The results reveal that the developed DDRL-based solution vastly outperforms not only conventional methods but also other machine-learning-based benchmark techniques. The main contribution of this thesis is to provide an intelligent framework for mobility man agement in the connected state (i.e HO management) in 5G. Though primarily developed for mm-wave links between UEs and BSs in ultra-dense heterogeneous networks (UDHNs), the proposed framework can also be applied to sub-6 GHz frequencies