A Feasibility Analysis of the Use of IEEE 802.11ah to extend 4G Network Coverage

The 4G LTE network has been launched in many countries including Indonesia, and all telecommunications operators are competing to expand their service coverage. Due to various reasons, there are a lot of areas that remains uncovered by the 4G LTE network. With the increase in cellular traffic, operators must continue to improve their service coverage. One of the scenarios to expand the service coverage is by offloading the traffic to a more cost-effective 802.11ah network in which one 802.11ah access point can serve thousands of mobile devices and support the Machine-to-Machine (M2M)/Internet of Things (IoT) communication. This study simulates the effect of the number of nodes on MCS performance evaluation of the 802.11ah protocol. The simulation is conducted by utilizing NS3 software to evaluate the throughput, delay, packet delivery ratio and energy consumption. This study also simulates 802.11ah coverage prediction to expand the LTE networks by utilizing Atoll Radio Planning Software. The results show that the performance obtained by varying the number of nodes/users from 100 to 1000 nodes is technically acceptable. In addition, the service coverage of 802.11ah network can solve the problem of blank spot area

Performance Evaluation of Wireless Medium Access Control Protocols for Internet of Things

The Internet of Things makes the residents in Smart Cities enjoy a more efficient and high-quality lifestyle by wirelessly interconnecting the physical and visual world. However, the performance of wireless networks is challenged by the ever-growing wireless traffic data, the complexity of the network structures, and various requirements of Quality of Service (QoS), especially on the Internet of Vehicle and wireless sensor networks. Consequently, the IEEE 802.11p and 802.11ah standards were designed to support effective inter-vehicle communications and large-scale sensor networks, respectively. Although their Medium Access Control protocols have attracted much research interest, they have yet to fully consider the influences of channel errors and buffer sizes on the performance evaluation of these Medium Access Control (MAC) protocols. Therefore, this thesis first proposed a new analytical model based on a Markov chain and Queuing analysis to evaluate the performance of IEEE 802.11p under imperfect channels with both saturated and unsaturated traffic. All influential factors of the Enhanced Distributed Channel Access (EDCA) mechanism in IEEE 802.11p are considered, including the backoff counter freezing, Arbitration Inter-Frame Spacing (AIFS) defers, the internal collision, and finite MAC buffer sizes. Furthermore, this proposed model considers more common and actual conditions with the influence of channel errors and finite MAC buffer sizes. The effectiveness and accuracy of the developed model have been validated through extensive ns-3 simulation experiments. Second, this thesis proposes a developed analytical model based on Advanced Queuing Analysis and the Gilbert-Elliot model to analyse the performance of IEEE 802.11p with burst error transmissions. This proposed analytical model simultaneously describes transmission queues for all four Access Categories (AC) queues with the influence of burst errors. Similarly, this presented model can analyse QoS performance, including throughputs and end-to-end delays with the unsaturated or saturated load traffics. Furthermore, this model operates under more actual bursty error channels in vehicular environments. In addition, a series of simulation experiments with a natural urban environment is designed to validate the efficiency and accuracy of the presented model. The simulation results reflect the reliability and effectiveness of the presented model in terms of throughput and end-to-end delays under various channel conditions. Third, this thesis designed and implemented a simulation experiment to analyse the performance of IEEE 802.11ah. These simulation experiments are based on ns-3 and an extension. These simulation experiments' results indicate the Restricted Access Window (RAW) mechanism's influence on the throughputs, end-to-end delays, and packet loss rates. Furthermore, the influences of channel errors and bursty errors are considered in the simulations. The results also show the strong impact of channel errors on the performance of IEEE 802.11ah due to urban environments. Finally, the potential future work based on the proposed models and simulations is analysed in this thesis. The proposed models of IEEE 802.11p can be an excellent fundamental to optimise the QoS due to the precise evaluation of the influence of factors on the performance of IEEE 802.11p. Moreover, it is possible to migrate the analytical models of IEEE 802.11p to evaluate the performance of IEEE 802.11ah

Contributions to IEEE 802.11-based long range communications

The most essential part of the Internet of Things (IoT) infrastructure is the wireless communication system that acts as a bridge for the delivery of data and control messages between the connected things and the Internet. Since the conception of the IoT, a large number of promising applications and technologies have been developed, which will change different aspects in our daily life. 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, IEEE 802.11ah is an Internet of Things enabling technology, where the efficient management of thousands of devices is a key function. 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. To this aim, IEEE 802.11ah provides the Restricted Access Window (RAW) mechanism, which reduces contention by enabling transmissions for small groups of stations. Optimal grouping of RAW stations requires an evaluation of many possible configurations. In this thesis, 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 possibly long distances. 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. Additionally, we expose the capabilities of future IEEE 802.11ah in supporting different IoT applications. In addition, we provide a brief overview of the technology contenders that are competing to cover the IoT communications framework. Numerical results are presented showing how the future IEEE 802.11ah specification offers the features required by IoT communications, thus putting forward IEEE 802.11ah as a technology to cater the needs of the Internet of Things paradigm. Finally, we propose an analytical model (named e-model) that provides an evaluation of the RAW onfiguration performance, allowing a fast adaptation of RAW grouping policies, in accordance to varying channel conditions. We base the e-model in known saturation models, which we adapted to include the IEEE 802.11ah’s PHY and MAC layer modifications and to support different bit rate and packet sizes. As a proof of concept, we use the proposed model to compare the performance of different grouping strategies,showing that the e-model is a useful analysis tool in RAW-enabled scenarios. We validate the model with existing IEEE 802.11ah implementation for ns-3.La clave del concepto Internet de las cosas (IoT) es que utiliza un sistema de comunicación inalámbrica, el cual actúa como puente para la entrega de datos y mensajes de control entre las "cosas" conectadas y el Internet. Desde la concepción del IoT, se han desarrollado gran cantidad de aplicaciones y tecnologías prometedoras que cambiarán distintos aspectos de nuestra vida diaria.Sin embargo, las tecnologías de redes computacionales inalámbricas existentes carecen de la capacidad de soportar las características del IoT, como las grandes cantidades de envío y recepción de datos desde múltiples dispositivos distribuidos en un área amplia, donde los dispositivos IoT funcionan con baterías. Para respaldar el paradigma del IoT, IEEE 802.11ah, la cual es una tecnología habilitadora del Internet de las cosas, para el cual la gestión eficiente de miles de dispositivos es una función clave. IEEE 802.11ah es uno de los estándares más prometedores y atractivos, desde su concepción orientada para IoT, su objetivo principal es cerrar la brecha entre las redes móviles tradicionales y la demandada por el IoT. Con este objetivo en mente, IEEE 802.11ah incluye entre sus características especificas el mecanismo de ventana de acceso restringido (RAW, por sus siglas en ingles), el cual define un nuevo período de acceso al canal libre de contención, reduciendo la misma al permitir transmisiones para pequeños grupos de estaciones. Nótese que para obtener una agrupación óptima de estaciones RAW, se requiere una evaluación de las distintas configuraciones posibles. En esta tesis, primero discutimos las principales mejoras de las capas PHY y MAC propuestas para IEEE 802.11ah. Además, investigamos la operatividad de IEEE 802.11ah como enlace de backhaul para conectar dispositivos a distancias largas. También, comparamos el estándar antes mencionado con las notables especificaciones IEEE 802.11 anteriores (es decir, IEEE 802.11n y IEEE 802.11ac), en términos de rendimiento (incluyendo y excluyendo la agregación de tramas de datos) y utilizando los esquemas de modulación más robustos. Los resultados muestran mejores resultados en cuanto al rendimiento de IEEE 802.11ah (en términos de potencia recibida a largo alcance, mientras se experimentan diferentes tasas de error de paquetes de datos) en comparación con los estándares IEEE 802.11 anteriores.Además, exponemos las capacidades de IEEE 802.11ah para admitir diferentes aplicaciones de IoT. A su vez, proporcionamos una descripción general de los competidores tecnológicos, los cuales contienden para cubrir el marco de comunicaciones IoT. También se presentan resultados numéricos que muestran cómo la especificación IEEE 802.11ah ofrece las características requeridas por las comunicaciones IoT, presentando así a IEEE 802.11ah como una tecnología que puede satisfacer las necesidades del paradigma de Internet de las cosas.Finalmente, proponemos un modelo analítico (denominado e-model) que proporciona una evaluación del rendimiento utilizando la característica RAW con múltiples configuraciones, el cual permite una rápida adaptación de las políticas de agrupación RAW, de acuerdo con las diferentes condiciones del canal de comunicación. Basamos el e-model en modelos de saturación conocidos, que adaptamos para incluir las modificaciones de la capa MAC y PHY de IEEE 802.11ah y para poder admitir diferentes velocidades de transmisión de datos y tamaños de paquetes. Como prueba de concepto, utilizamos el modelo propuesto para comparar el desempeño de diferentes estrategias de agrupación, mostrando que el e-model es una herramienta de análisis útil en escenarios habilitados para RAW. Cabe mencionar que también validamos el modelo con la implementación IEEE 802.11ah existente para ns-3

Implementação do protocolo IEEE 802.11ah através de rádio definido por software

O crescente uso de redes conhecidas como Internet das Coisas (IoT) constitui oportunidade para um vasto campo de pesquisa e desenvolvimento, onde diversos protocolos oferecem soluções práticas distintas. Entre estes, o protocolo IEEE 802.11ah é uma alternativa de livre implementação que utiliza uma faixa de espectro não licenciada abaixo de 1 GHz. Este trabalho oferece contribuições para a implementação de técnicas de comunicação adequadas a redes de sensores sem fio (WSN) baseadas no padrão IEEE 802.11ah (Wi-Fi HaLow). De forma a facilitar trabalhos futuros de pesquisa e devido a baixa disponibilidade de dispositivos comerciais, uma plataforma de rádio definido por software foi utilizada para realizar a implementação de um enlace em camada física a partir da especificação do protocolo e de uma implementação pré-existente que comtempla as características de modulação fundamentais do protocolo. Foram conduzidos testes e experimentos de bancada para avaliar o desempenho dos dispositivos, em situações de interferência e ruído. As condições de interferência foram um sinal senoidal, um sinal LoRa e um sinal O-QPSK derivado do protocolo IEEE 802.15.4, uma vez que ocupam a mesma banda de frequências do protocolo avaliado. Também foi avaliada a rejeição a sinais interferente IEEE 802.11ah sobrepostos no mesmo canal, em canal adjacente e em canal não adjacente. As simulações e experimentos geraram um conjunto de dados que foram analisados conforme os requisitos da especificação e da literatura, atendendo o desempenho especificado. Os valores limites para estas interferências são demonstrados em termos de diferenças de potências. O código-fonte será disponibilizado publicamente, para servir de base a trabalhos futuros que tenham por objetivo avaliar o desempenho do protocolo IEEE 802.11ah sob outros aspectos ou provar ideias teóricas inovadoras que, embora propostas e demonstradas de forma simulada, por vezes não encontram comprovação em hardware.The Internet of Things (IoT) environment is an expanding field with many competing standards solving various communication challenges. However, interesting theoretical propositions, demonstrated in simulations during research, end up not getting a quick implementation in hardware. This work provides contributions towards an implementation of the IEEE 802.11ah (Wi-Fi HaLow) standard, an extension of the Wi-Fi protocol focused on providing IoT-like connectivity on midrange sites (up to 1 km). A softwaredefined radio plataform, programmed with open-source software, is used to provide an extensible code base, derived from existing works. Simulation and experimental measurements were conducted towards evaluating the performance and limitations in interference and noise environments. As interference, sinusoidal, LoRa and IEEE 802.15.4 O-QPSK derived signals were used as to evaluate the minimum difference of powers necessary to garantee the IEEE 802.11ah signal is received and correctly decoded with 90 % packet delivery rate. Adjacent, non adjacent and same channel rejection were also evaluated. All results agree with the requirements presented in the standard. We make the source code freely available in the Internet as to enable future modifications and derived works

Integrating energy harvesting within the IoT ecosystem for sustainable wireless communication

This dissertation addresses the challenges posed by the energy demands of IoT devices, highlighting the limitations of conventional batteries, which lead to high maintenance costs and environmental concerns. It proposes integrating Energy Harvesting (EH) technologies to extend device lifespan and reduce environmental impact. The research focuses on optimizing the Medium Access Control (MAC) layer to manage energy consumption in Wi-Fi-based IoT systems, particularly in e healthcare environments. A comprehensive framework is developed for assessing energy consumption across various wireless technologies. The study utilizes simulations in a densely deployed solar-powered Wi-Fi network, introducing an optimization algorithm for Access Point coordination and Reinforcement Learning (RL) methods to adapt to network dynamics. The findings demonstrate that fine-tuning MAC layer parameters and implementing a sleep/wake-up strategy significantly reduce energy consumption while maintaining Quality of Service (QoS). The work provides valuable insights for enhancing energy efficiency in IoT systems through EH technologies.Tecnologías de la información y de rede

Design of Real-Time Simulation Testbed for Advanced Metering Infrastructure (Ami) Network

Conventional power grids are being superseded by smart grids, which have smart meters as one of the key components. Currently, for the smart metering communication, wireless technologies have predominantly replaced the traditional Power Line Communication (PLC). Different vendors manufacture smart meters using different wireless communication technologies. For example, some vendors use WiMAX, others prefer Low-Power Wireless Personal Area Networks (Lo-WPAN) for the Media Access Control (MAC) and physical layer of the smart meter network, also known as Advanced Metering Infrastructure (AMI) network. Different communication techniques are used in various components of an AMI network. Thus, it is essential to create a testbed to evaluate the performance of a new wireless technology or a novel protocol to the network. It is risky to study cyber-security threats in an operational network. Hence, a real-time simulation testbed is considered as a substitute to capture communication among cyber-physical subsystems. To design the communication part of our testbed, we explored a Cellular Internet of Things (CIoT) : Co-operative Ultra NarrowBand (C-UNB) technology for the physical and the MAC layer of the Neighborhood Area Network (NAN) of the AMI. After successful evaluation of its performance in a Simpy python simulator, we integrated a module into Network Simulator-3 (NS-3). As NS-3 provides a platform to incorporate real-time traffic to the AMI network, we can inject traffic from power simulators like Real Time Digital Simulator (RTDS). Our testbed was used to make a comparative study of different wireless technologies such as IEEE 802.11ah, WiMAX, and Long Term Evolution (LTE). For the traffic, we used HTTP and Constrained Application Protocol (CoAP), a widely used protocol in IoT. Additionally, we integrated the NS-3 module of Device Language Message Specification - Companion Specification for Energy Metering (DLMS-COSEM), that follows the IEC 62056 standards for electricity metering data exchange. This module which comprises of application and transport layers works in addition with the physical and MAC layer of the ii C-UNB module. Since wireless communication is prone to eavesdropping and information leakages, it is crucial to conduct security studies on these networks. Hence, we performed some cyber-attacks such as Denial of Service (DoS), Address Resolution Protocol (ARP) spoofing and Man-in-the-Middle (MiTM) attacks in the testbed, to analyze their impact on normal operation of AMI network. Encryption techniques can alleviate the issue of data hijacking, but makes the network traffic invisible, which prevents conventional Intrusion Detection Systems (IDS) from undertaking packet-level inspection. Thus, we developed a Bayesian-based IDS for ARP spoof detection to prevent rogue smart meters from modifying genuine data or injecting false data. The proposed real time simulation testbed is successfully utilized to perform delay and throughput analysis for the existing wireless technologies alongwith the evaluation of the novel features of C-UNB module in NS-3. This module can be used to evaluate a broad range of traffic. Using the testbed we also validated our IDS for ARP spoofing attack. This work can be further utilized by security researchers to study different cyber attacks in the AMI network and propose new attack prevention and detection solution. Moreover, it can also allow wireless communication researchers to improve our C-UNB module for NS-3

Passive Positioning Approaches in the Future Positioning Systems

Wireless Local Area Networks (WLAN) are extending its fields of application and and, in addition, they start to support the indoor wireless positioning. Nevertheless, the challenges they have to deal with are highly compelling, since indoor environments are surronded by walls, floors, obstacles,etc., that affect the signal propagation and, therefore, the accuracy of the positioning. The thesis work addressed here aims to explore the features and the performance of a new positioning technique to be applied in indoor environments in future WLANs. The proposed technique consists of a passive positioning approach based on two well-known methods for positioning: distance-based and angle-based algorithms. Moreover, the used to standarize technique is developed on the basis of the new amendment of IEEE 802.11az in order to standarize the Next Generation Position Systems (NGP). Therefore, the scope of the thesis work is mainly to verify whether the proposed passive positioning technique suits the requirements specified in 802.11az amendment through simulating different use cases. A Matlab GUI interface has been created to test and compare various 802.11az-based scenarios. The main thesis findings are that, in order to support a positioning accuracy below 0.1m, timing measurements should have a maximum error variance of 80 ns and pure angle-based measurements are not sufficient

Accurate Energy Modeling and Characterization of IEEE 802.11ah RAW and TWT

Minimizing the energy consumption is one of the main challenges in internet of things (IoT) networks. Recently, the IEEE 802.11ah standard has been released as a new low-power Wi-Fi solution. It has several features, such as restricted access window (RAW) and target wake time (TWT), that promise to improve energy consumption. Specifically, in this article we study how to reduce the energy consumption thanks to RAW and TWT. In order to do this, we first present an analytical model that calculates the average energy consumption during a RAW slot. We compare these results to the IEEE 802.11ah simulator that we have extended for this scope with an energy life-cycle model for RAW and TWT. Then we study the energy consumption under different conditions using RAW. Finally, we evaluate the energy consumption using TWT. In the results, we show that the presented model has a maximum deviation from the simulations of 10% in case of capture effect (CE) and 7% without it. RAW always performs better than carrier-sense multiple access with collision avoidance (CSMA/CA) when the traffic is higher and the usage of more slots has showed to have better energy efficiency, of up to the 76%, although also significantly increasing the latency. We will show how TWT outperforms pure RAW, by over 100%, when the transmission time is over 5 min