Uplink power control modeling for dense OFDMA-based heterogeneous networks

In this paper we propose a novel model for the uplink in heterogeneous cellular networks. Opposed to previous works, we accurately account for the mutual interference caused by other users’ connections, and we pose an optimization problem that can be straightforwardly solved to establish the minimum required transmission power that satisfies the minimum Signal-to-Interferenceplus-Noise Ratio (SINR) constraint. We assess the validity of the proposed approach by comparing the observed results with those obtained with a traditional closed-loop power control scheme. The main benefit of our solution is that it does not require any iteration to find the transmission power, while legacy approaches usually need a number of steps before finding it. Finally, we study the behavior of the uplink for different access selection strategies, and we compare the SINR and transmission power of open-loop and closed-loop power control solutions.This work has been supported by the Spanish Government (Ministerio de Economía y Competitividad, Fondo Europeo de Desarrollo Regional, FEDER) by means of the projects ADVICE: Dynamic provisioning of connectivity in high density 5G wireless scenarios (TEC2015-71329-C2-1-R) and Future Internet Enabled Resilient Cities (FIERCE)

Electromagnetic field assessment as a smart city service: The SmartSantander use-case

Despite the increasing presence of wireless communications in everyday life, there exist some voices raising concerns about their adverse effects. One particularly relevant example is the potential impact of the electromagnetic field they induce on the population's health. Traditionally, very specialized methods and devices (dosimetry) have been used to assess the strength of the E-field, with the main objective of checking whether it respects the corresponding regulations. In this paper, we propose a complete novel approach, which exploits the functionality leveraged by a smart city platform. We deploy a number of measuring probes, integrated as sensing devices, to carry out a characterization embracing large areas, as well as long periods of time. This unique platform has been active for more than one year, generating a vast amount of information. We process such information, and the obtained results validate the whole methodology. In addition, we discuss the variation of the E-field caused by cellular networks, considering additional information, such as usage statistics. Finally, we establish the exposure that can be attributed to the base stations within the scenario under analysis.This work has been supported by the Spanish Government (Ministerio de Economía y Competitividad, Fondo Europeo de Desarrollo Regional, FEDER) by means of the project ADVICE: Dynamic provisioning of connectivity in high density 5G wireless scenarios (TEC2015-71329-C2-1-R)

Fostering inter-operable urban ecosystems through the adoption of common frameworks

Worldwide cities are involved in a digital transformation phase. More sustainable cities and improving citizen’s quality of life are the leit motiv of such transformation. However, such aims are difficult to achieve if the migration of the urban processes are not carried out following a common approach. Optimizing the behavior of any specific urban service needs to be performed taking into consideration both the service itself as well as its interaction with adjacent services. This means that any solution aiming to achieve the autonomous city management paradigm is tightly related to the adoption of common frameworks which are able to guarantee interoperability with other systems. Furthermore, cities themselves are not isolated systems. Well the opposite, cities interact one to the each other depending on different attributes. This implies that sooner or later optimizing some processes in one city without having in mind the adjacency to others might not be efficient enough. Hence, interoperability among cities will become a must, not just in terms of optimization but also replicability. Based on this boundary conditions this paper describes a framework aimed to ensure interoperability and replicability among cities. Some of the tools for assessing compliance with specific standardization activities are also presented.This work has been partially funded by the European Union’s Horizon 2020 Programme under Grant Agreement No. 732240 SynchroniCity (Delivering an IoT enabled Digital Single Market for Europe and Beyond). The content of this paper does not reflect the official opinion of the European Union. Responsibility for the information and views expressed therein lies entirely with the authors. In addition, this work has been also partially funded by the Spanish Government (MINECO) under Grant Agreement No. RTI2018-093475-AI00 FIERCE (Future Internet Enabled Resilient smart CitiEs

Fostering IoT service replicability in interoperable urban ecosystems

Worldwide cities are involved in a digital transformation phase specially focused on sustainability and improving citizen's quality of life. However, such objectives are hard to achieve if the migration of the urban processes are not performed following a common approach. Under the paradigm of smart city, different Information and Communication Technologies (ICT) have been deployed over urban environments to enable such digital transformation. However, actual implementations differ from one city to another, and even between services within the same city. As a consequence, the deployment of urban services is hindered, since they need to be tailored to each city. In addition, the isolation of urban services obstructs its optimization, since it cannot harness contextual information coming from other services. All in all, it is necessary to implement tools and mechanisms that allow us to ensure that city solutions and their vertical services are interoperable. In order to tackle this issue, different initiatives have proposed architectures that homogenize the interaction with smart cities from different angles. However, so far the compliance with such architectures has not been assessed. Having this in mind, in this work we present a validation framework, developed under the umbrella of the SynchroniCity project, which aims to verify that interfaces and data exposed by cities are aligned with the adopted standards and data models. In this regard, the validation framework presented here is the technical enabler for the creation of an interoperability certi cate for smart cities. To assess the bene ts of the validation framework, we have used it to check the interoperability of 21 smart city deployments worldwide that adhered the SynchroniCity guidelines. Afterwards, during an open call a total number of 37 services have been deployed over such SynchroniCity instances, thus con rming the goodness of uniform and validated smart cities to foster service replicability.This work was supported in part by the European Union’s Horizon 2020 Programme [SynchroniCity (Delivering an IoT enabled Digital Single Market for Europe and Beyond)] under Grant 732240, and in part by the Spanish Government (Ministerio de Economía y Competitividad, Fondo Europeo de Desarrollo Regional, MINECO-FEDER) through the project FIERCE: Future Internet Enabled Resilient smart CitiEs under Grant RTI2018-093475-AI00

A geometric programming solution for the mutual-interference model in HetNets

It is well known that the use of heterogeneous networks and densification strategies will be crucial to handle the wireless cellular traffic increase that is foreseen in the forthcoming years. Hence, the scientific community is putting effort into the proposal and assessment of radio resource management solutions for this type of deployments. For that, an accurate modeling of the underlying resources is mandatory. In this letter, we propose a mutual-interference model, which enables a precise estimation of the signal-to-interference and noise ratio (SINR), compared with the widespread constant-load alternative. This is of utter relevance, since the SINR has a direct influence on the spectral efficiency and, consequently, on the resources to be allocated. We also propose a transformation of the corresponding resource assignment problem, so that it can be solved using geometric programming techniques. The validity of this transformation is assessed by comparing the corresponding solution with the one that would have been obtained exploiting a heuristic approach (simulated annealing).This work has been supported by the Spanish Government (Ministerio de Economía y Competitividad, Fondo Europeo de Desarrollo Regional, FEDER) by means of the projects COSAIF, Connectivity as a Service: Access for the Internet of the Future (TEC2012-38754-C02-01), and ADVICE, Dynamic provisioning of connectivity in high density 5G wireless scenarios (TEC2015-71329-C2-1-R

Minimizing delay in NFV 5G networks by means of flexible split selection and scheduling

It is well known that network function virtualization will be a key enabler to meet the stringent requirements of 5G networks. However, fully centralized approaches, such as Cloud Radio Access Network (C-RAN), might not be feasible, considering the particular needs of the fronthaul links and the large cost of implementing such architectural shift. In this sense, flexible functional split brings a practical solution, which trades off performance and practicability. In spite of the growing interest in flexible functional split, little attention has been paid to the interaction of split selection and scheduling. In this paper, we analyze joint strategies that minimize traffic delay. We compare the global optimum solution with partial optimizations, that can be more suitable in practical implementations, using different scenarios. According to our results, fixed scheduling behaves alike the global optimum in heterogeneous RAN scenarios.This work has been supported by the Spanish Government (Ministerio de Economía y Competitividad, Fondo Europeo de Desarrollo Regional, FEDER) by means of the projects ADVICE: Dynamic provisioning of connectivity in high density 5G wireless scenarios (TEC2015-71329-C2-1-R) and Future Internet Enabled Resilient Cities (FIERCE)

Experimentation management in the co-created smart-city: Incentivization and citizen engagement

Under the smart city paradigm, cities are changing at a rapid pace. In this context, it is necessary to develop tools that allow service providers to perform rapid deployments of novel solutions that can be validated by citizens. In this sense, the OrganiCity experimentation-as-a-service platform brings about a unique solution to experiment with new urban services in a co-creative way, among all the involved stakeholders. On top of this, it is also necessary to ensure that users are engaged in the experimentation process, so as to guarantee that the resulting services actually fulfill their needs. In this work, we present the engagement monitoring framework that has been developed within the OrganiCity platform. This framework permits the tailored definition of metrics according to the experiment characteristics and provides valuable information about how citizens react to service modifications and incentivization campaigns.This research was funded by the European Union’s Horizon 2020 Framework Programme grant number 645198

A Quasi-Birth-Death model for functional split in 5G controllers

It is broadly accepted that network function virtualization will play a key role to meet the stringent and heterogeneous requirements of 5G networks. Although fully centralized approaches were initially proposed, they may impose unfeasible requirements over fronthaul links. Consequently, flexible functional split solutions are being fostered, where a central controller adapts the centralization level to current circumstances. In spite of the growing interest in this type of solutions, most of existing works focus on real implementation, while little attention has been paid so far to performance modeling. In this paper we propose a Markov Chain based controller model, which boils down to a Quasi-Birth-Death process. Under reasonable assumptions, this model provides expected values of buffer occupancy and the time frames would spend in the controller. In this sense, it aims to be a tool to support the allocation of computational resources of the virtualized entities. We validate the proposed model by comparing its results with those obtained by simulation, evincing an almost perfect match between both approaches.This work has been funded by the Spanish Government (Ministerio de Economía y Competitividad, Fondo Europeo de Desarrollo Regional, MINECO-FEDER) by means of the project FIERCE: Future Internet Enabled Resilient smart CitiEs (RTI2018-093475-AI00)

Modelado del control de potencia del enlace ascendente para redes heterogéneas y densas basadas en OFDMA

En este trabajo se presenta un modelado novedoso del enlace ascendente en redes heterogéneas, que se ha planteado para su uso en simulación a nivel de sistema. A diferencia de otros trabajos, el modelo propuesto tiene en cuenta la interferencia mutua causada por las conexiones de otros usuarios, y establece los niveles de potencia mínimos necesarios para satisfacer una Relación Señal a Ruido e Interferencia (SINR) arbitraria. El planteamiento da lugar a un problema de optimización lineal que se puede resolver de manera sencilla con diferentes herramientas. A fin de validar el modelo, se ha comparado el rendimiento obtenido al aplicarlo con el observado al utilizar un esquema tradicional de lazo cerrado, implementado de forma iterativa. El análisis demuestra que el modelo propuesto proporciona, en una sola iteración, los mismos resultados que los métodos de simulación iterativos, permitiendo, por lo tanto, reducir la complejidad de las simulaciones. Finalmente, se ha estudiado el comportamiento del modelo en escenarios heterogéneos, haciendo uso de diferentes técnicas de selección de acceso.Los autores agradecen la financiación del Gobierno de España (Ministerio de Economía y Competitividad, Fondo Europeo de Desarrollo Regional, FEDER) de este trabajo a través de los proyectos ADVICE: Dynamic provisioning of connectivity in high density 5G wireless scenarios (TEC2015-71329-C2-1-R) y FIERCE: Future Internet Enabled Resilient Cities (RTI2018-093475-A-100)

Understanding the performance of flexible functional split in 5G vRAN controllers: A Markov Chain-based model

We study Flexible Functional Split functionality of 5G vRAN controllers in 5G networks. We propose an innovative model, based on a Markov Chain, which can be used to characterize their performance. We consider both infinite and finite-buffer controllers. In the former, frames would not be lost (provided the system works in a stable regime), and we thus focus on the time frames stay at the controller. For the finite-buffer controller, there might be losses, and we analyze the trade-off between time at the controller (which might hinder the stringent delay requirements of 5G services), and loss probability. Matrix-geometric techniques are used to resolve the corresponding Quasi-Birth-Death process. The validity of the proposed model is assessed by means of an extensive experiment campaign carried out over an ad-hoc eventdriven simulator, which is also used to broaden the analysis, considering different service rate distributions, as well as the variability of the studied performance indicators. The results show that the proposed model can be effectively exploited to tackle the dimensioning of these systems, as it sheds light on how their configuration impacts the expected delay and loss rate.This work has been funded by the Spanish Government (Ministerio de Economía y Competitividad, Fondo Europeo de Desarrollo Regional, MINECO-FEDER) by means of the project FIERCE: Future Internet Enabled Resilient smart CitiEs (RTI2018-093475-AI00)