Throughput and range characterization of IEEE 802.11ah

The most essential part of Internet of Things (IoT) infrastructure is the wireless communication system that acts as a bridge for the delivery of data and control messages. However, the existing wireless technologies lack the ability to support a huge amount of data exchange from many battery driven devices spread over a wide area. In order to support the IoT paradigm, the IEEE 802.11 standard committee is in process of introducing a new standard, called IEEE 802.11ah. This is one of the most promising and appealing standards, which aims to bridge the gap between traditional mobile networks and the demands of the IoT. In this paper, we first discuss the main PHY and MAC layer amendments proposed for IEEE 802.11ah. Furthermore, we investigate the operability of IEEE 802.11ah as a backhaul link to connect devices over a long range. Additionally, we compare the aforementioned standard with previous notable IEEE 802.11 amendments (i.e. IEEE 802.11n and IEEE 802.11ac) in terms of throughput (with and without frame aggregation) by utilizing the most robust modulation schemes. The results show an improved performance of IEEE 802.11ah (in terms of power received at long range while experiencing different packet error rates) as compared to previous IEEE 802.11 standards.Comment: 7 pages, 6 figures, 5 table

Joint Access-Backhaul Perspective on Mobility Management in 5G Networks

The ongoing efforts in the research development and standardization of 5G, by both industry and academia, have resulted in the identification of enablers (Software Defined Networks, Network Function Virtualization, Distributed Mobility Management, etc.) and critical areas (Mobility management, Interference management, Joint access-backhaul mechanisms, etc.) that will help achieve the 5G objectives. During these efforts, it has also been identified that the 5G networks due to their high degree of heterogeneity, high QoS demand and the inevitable density (both in terms of access points and users), will need to have efficient joint backhaul and access mechanisms as well as enhanced mobility management mechanisms in order to be effective, efficient and ubiquitous. Therefore, in this paper we first provide a discussion on the evolution of the backhaul scenario, and the necessity for joint access and backhaul optimization. Subsequently, and since mobility management mechanisms can entail the availability, reliability and heterogeneity of the future backhaul/fronthaul networks as parameters in determining the most optimal solution for a given context, a study with regards to the effect of future backhaul/fronthaul scenarios on the design and implementation of mobility management solutions in 5G networks has been performed.Comment: IEEE Conference on Standards for Communications & Networking, September 2017, Helsinki, Finlan

Bandwidth-Based Wake-Up Radio solution through IEEE 802.11 technology

IEEE 802.11 consists of one of the most used wireless access technologies, which can be found in almost all consumer electronics devices available. Recently, Wake-up Radio (WuR) systems have emerged as a solution for energy-efficient communications. WuR mechanisms rely on using a secondary low-power radio interface that is always in the active operation mode and is in charge of switching the primary interface, used for main data exchange, from the power-saving state to the active mode. In this paper, we present a WuR solution based on IEEE 802.11 technology employing transmissions of legacy frames by an IEEE 802.11 standard-compliant transmitter during a Transmission Opportunity (TXOP) period. Unlike other proposals available in the literature, the WuR system presented in this paper exploits the PHY characteristics of modern IEEE 802.11 radios, where different signal bandwidths can be used on a per-packet basis. The proposal is validated through the Matlab software tool, and extensive simulation results are presented in a wide variety of scenario configurations. Moreover, insights are provided on the feasibility of the WuR proposal for its implementation in real hardware. Our approach allows the transmission of complex Wake-up Radio signals (i.e., including address field and other binary data) from legacy Wi-Fi devices (from IEEE 802.11n-2009 on), avoiding hardware or even firmware modifications intended to alter standard MAC/PHY behavior, and achieving a bit rate of up to 33 kbps.Postprint (published version

A transmit power control proposal for IEEE 802.11 cellular networks

Actually, the idea of designing an outdoor cellular network based on WLAN IEEE 802.11 results very attractive, due to the several advantages that this technology presents. It offers the equipment at a lower cost, operates in unlicensed spectrum and allows higher data rates.If we realize a comparison of the system performance between a cellular environment and an isolated single cell scenario we observe that the first situation exhibits a considerable decrease, due to co-channel interference, that rises with the growth of the transmission data rate employed. In this paper, we propose a power control mechanism, as a method to reduce the interference influence on network performance, and to homogenize the behavior of the different stations in the system. We present its performance under different load conditions and compare this behavior with the original case, without the employment of any power control mechanism.Peer Reviewe

Evolutionary 4G/5G network architecture assisted efficient handover signaling

Future wireless networks are expected to be ultra-dense and heterogeneous not just in terms of the number and type of base stations but also in terms of the number of users and the application types they access. Such a network architecture will require mobility management mechanisms that adapt rapidly to these highly dynamic network characteristics. In particular, the optimality of the handover signaling within these future network architectures will be extremely critical given their density and heterogeneity. In this paper, the optimality is relevant for both the total amount of signaling created and the total delay per handover process. In this paper, we first present a novel and optimized message mapping and signaling mechanism for the handover preparation and failure phases. We also develop a novel handover failure aware preparation signaling methodology, which accounts for the possibility of a handover failure and grants additional enhancements to the handover preparation and failure signaling phases. Through the analytical framework provided in this paper, we conduct studies to quantify the performance gains promised by the proposed mechanisms. These studies cover myriad handover scenarios as identified by 3GPP and use the statistics from cellular network operators and vendors. We then develop the idea and analytical framework for network wide analysis, in which the network wide processing cost and network occupation time for various handover failure rates are computed. Finally, we propose an evolutionary network architecture that facilitates the proposed signaling mechanism as well as assists operators in maintaining a manageable capital expenditure. It combines the current day and 3GPP proposed 5G network architecture with the software-defined networking approach. As a result, we argue that the proposed mechanisms are viable and outperform the legacy handover signaling mechanisms in terms of latency incurred, total network occupation time, number of messages generated, and total bytes transferred.Peer ReviewedPostprint (author's final draft

Territorio de explotación minero de Riotinto. Una perspectiva analítica de la ocupación social romana

Presentamos algunas consideraciones sobre la evolución ocupacional del territorio minero de Riotinto durante el segmento de ocupación romano, desde perspectivas de un análisis materialista histórico, que pretende superar las explicaciones de orden formal e incidencias de orden funcionalista que han caracterizado las investigaciones arqueológicas a lo largo de 30 años en este coto minero. Planteándolas de forma preliminar para fundamentar vías alternativas de exploración desde inferencias con base empírica. Con un objetivo último, el estudio territorial en base a una explicación de la sociedad minera diseccionada como sociedad de clases

Analysis of the penetration of the digital transformation in the business sector in Europe and Spain during the period 2014-2021.

Este trabajo tiene como objeto el análisis dinámico de la penetración digital en el ámbito empresarial durante el periodo comprendido entre los años 2014 y 2021, comparando los datos de Europa y España. La penetración digital en las empresas será medida a través de dos subgrupos: el comercio electrónico y la posesión de tecnologías de digitalización empresarial, el primero de ellos será estudiado según el tamaño de las empresas. Estos subgrupos serán divididos a su vez en diferentes variables que serán analizadas tanto en Europa, dividiendo el análisis a su vez en distintas regiones, como en España, en base a unos criterios estadísticos que nos permitirán sacar resultados descriptivos. Al final del trabajo, los resultados alcanzados muestran una evolución general positiva de las distintas variables a lo largo del periodo selecciona, así como una brecha entre las distintas regiones europeas. Además, el Covid-19 muestra un impacto beneficioso tanto para España como para Europa en la mayoría de las variables de transformación digital.This paper aims to dynamically analyse digital penetration in the business environment during the period from 2014 to 2021, comparing data from Europe and Spain. Digital penetration in firms will be measured through two subgroups: e-commerce and the possession of business digitisation technologies, the first of which will be studied according to the size of the firms. These subgroups will in turn be divided into different variables that will be analysed both in Europe, dividing the analysis into different regions, and in Spain, based on statistical criteria that will allow us to obtain descriptive results. At the end of the work, the results achieved show an overall positive evolution of the different variables throughout the selected period, as well as a gap between the different European 5 regions. Moreover, Covid-19 shows a beneficial impact for both Spain and Europe in most of the digital transformation variables.Universidad de Sevilla. Grado en Economí

Diseño e implementación del control de un coche autónomo con comunicación externa

Aquest projecte es centra en el disseny i la implementació del control d’un vehicle autònom i en la comunicació entre aquest i un ordinador. Addicionalment, de manera independent, s'hi inclou el control manual amb un comandament extern Bluetooth. El principal objectiu és aconseguir desenvolupar un òptim algorisme capaç de manipular l'automòbil amb la finalitat de recórrer un circuit, acotat per dues línies, sense sortir-se'n i de manera completament autònoma. D'aquesta manera, es fa servir un sistema ultrasònic de navegació idoni per a la localització del vehicle en un pla 2D. Mitjançant un ordinador extern es processa la informació captada i es realitzen una sèrie de càlculs per tal de determinar la velocitat i la direcció pertinents. Per acabar, s'envien els resultats a una Raspberry Pi 4 Model B que s'encarrega d'actuar sobre els motors per obtenir el moviment desitjat. Cal destacar que tant els codis programats com la comunicació entre la Raspberry Pi i l'ordinador s'implementen en ROS (Robot Operating System), mitjançant el llenguatge de programació d'alt nivell Python.El presente proyecto se centra en el diseño y la implementación del control de un vehículo autónomo y en la comunicación entre éste y un ordenador. Adicionalmente, de manera independiente, se incluye el control manual con un mando externo Bluetooth. El principal objetivo es lograr desarrollar un óptimo algoritmo capaz de manipular al automóvil con la finalidad de recorrer un circuito, acotado por dos líneas, sin salirse y de manera completamente autónoma. Para tales efectos, se emplea un sistema ultrasónico de navegación idóneo para la localización del vehículo en un plano 2D. Mediante un ordenador externo al vehículo se procesa la información captada y se realizan una serie de cálculos con el fin de determinar la velocidad y la dirección pertinentes. Por último, se envían los resultados a una Raspberry Pi 4 Model B, a bordo del vehículo, que se encarga de actuar sobre los motores para obtener el movimiento deseado. Destacar que tanto los códigos programados como la comunicación entre la Raspberry Pi y el ordenador se implementan en ROS (Robot Operating System), mediante el lenguaje de programación de alto nivel Python.This project focuses on the design and the implementation of the control of an autonomous vehicle and the communication between it and a computer. Additionally, manual control is included with an external Bluetooth control. The main objective is to develop an optimal algorithm capable of manipulating the automobile in order to follow a track, bounded by two lines, without diverting and completely autonomously. In this way, an ultrasonic navigation system is used with the purpose of locating the vehicle on a 2D plane. An external computer processed the information captured by the sensors, executing the implemented algorithm so as to determine the relevant speed and direction. Finally, the results are sent to a Raspberry Pi 4 Model B on board the vehicle, which is responsible of acting on the motors to obtain the desired movement. The programmed codes and the communication between the Raspberry Pi and the computer are implemented in ROS (Robot Operating System), using the high-level programming language Python