2^k*r factorial analysis of powersaving class I in IEEE 802.16e

One of the most promising technologies for fixed and mobile broadband wireless access is IEEE 802.16, also known as Wi-MAX. In IEEE 802.16e, which was released on 2005, to add mobility support, power saving is one of the most important features for the extension of mobile stations’ lifetime. In this thesis work, we provide a 2^k*r factorial analysis investigation of the performance of an IEEE 802.16e wireless net-work, where mobile stations are equipped with energy saving enabled devices. Two types of realistic traffic models are considered: web and large file transfer. The aim is to analyze the relative importance of configuration parameters and how to configure them to achieve best performance

Energy efficiency in next generation wireless networks: methodologies, solutions and algorithms

Mobile Broadband Wireless Access (BWA) networks will offer in the forthcoming years multiple and differentiated services to users with high mobility requirements, connecting via portable or wearable devices which rely on the use of batteries by necessity. Since such devices consume a relatively large fraction of energy for transmitting/receiving data over-the-air, mechanisms are needed to reduce power consumption, in order to increase the lifetime of devices and hence improve user’s satisfaction. Next generation wireless network standards define power saving functions at the Medium Access Control (MAC) layer, which allow user terminals to switch off the radio transceiver during open traffic sessions for greatest energy consumption reduction. However, enabling power saving usually increases the transmission latency, which can negatively affect the Quality of Service (QoS) experienced by users. On the other hand, imposing stringent QoS requirements may limit the amount of energy that can be saved. The IEEE 802.16e standard defines the sleep mode is power saving mechanism with the purpose of reducing energy consumption. Three different operation classes are provided, each one to serve different class of traffic: class I, best effort traffic, class II real time traffic and class III multicast traffic. Several aspects of the sleep mode are left unspecified, as it is usually done in standards, allowing manufacturers to implement their own proprietary solutions, thus gaining a competitive advantage over the rivals. The work of this thesis is aimed at verifying, the effectiveness of the power saving mechanism proposed into IEEE 802.16e standard, focusing on the mutual interaction between power saving and QoS support. Two types of delay constrained applications with different requirements are considered, i.e., Web and Voice over IP (VoIP). The performance is assessed via detailed packet-level simulation, with respect to several system parameters. To capture the relative contribution of all the factors on the energy- and QoS-related metrics, part of the evaluation is carried out by means of 2k · r! analysis. Our study shows that the sleep mode can achieve significant power consumption reduction, however, when real time traffic is considered a wise configuration of the parameters is mandatory in order to avoid unacceptable degradation of the QoS. Finally, based on the guidelines drawn through the analysis, we extend our contribution beyond a simple evaluation, proposing a power saving aware scheduling framework aimed at reducing further the energy consumption. Our framework integrates with existing scheduling policies that can pursue their original goals, e.g. maximizing throughput or fairness, while improving the energy efficiency of the user terminals. Its effectiveness is assessed through an extensive packet level simulation campaign

A Fog-based Distributed Look-up Service for Intelligent Transportation Systems

Future intelligent transportation systems and applications are expected to greatly benefit from the integration with a cloud computing infrastructure for service reliability and efficiency. More recently, fog computing has been proposed as a new computing paradigm to support low-latency and location-aware services by moving the execution of application logic on devices at the edge of the network in proximity of the physical systems, e.g. in the roadside infrastructure or directly in the connected vehicles. Such distributed runtime environment can support low-latency communication with sensors and actuators thus allowing functions such as real-time monitoring and remote control, e.g. for remote telemetry of public transport vehicles or remote control under emergency situations, respectively. These applications will require support for some basic functionalities from the runtime. Among them, discovery of sensors and actuators will be a significant challenge considering the large variety of sensors and actuators and their mobility. In this paper, a discovery service specifically tailored for fog computing platforms with mobile nodes is proposed. Instead of adopting a centralized approach, we pro-pose an approach based on a distributed hash table to be implemented by fog nodes, exploiting their storage and computation capabilities. The proposed approach supports by design multiple attributes and range queries. A prototype of the proposed service has been implemented and evaluated experimentally

Automating Large-Scale Simulation and Data Analysis with OMNeT++: Lession Learned and Future Perspectives

Simulation is widely adopted in the study of modern computer networks. In this context, OMNeT++ provides a set of very effective tools that span from the definition of the network, to the automation of simulation execution and quick result representation. However, as network models become more and more complex to cope with the evolution of network systems, the amount of simulation factors, the number of simulated nodes and the size of results grow consequently, leading to simulations with larger scale. In this work, we perform a critical analysis of the tools provided by OMNeT++ in case of such large-scale simulations. We then propose a unified and flexible software architecture to support simulation automation

On the impact of urban micro climate on the energy consumption of buildings

The energy consumption of urban buildings is affected by the surrounding microclimate which differs from standard weather data and by mutual obstructions between buildings, which decrease sunlight and wind potentials for internal solar gains and passive cooling. The building construction itself affects both outdoor and indoor microclimate. This research addresses these interdependences in respect with energy performance. An urban structures are investigated with a fixed value of H/W and solar orientation. The numerical method used is the building energy model (TRNSYS), for simulating building energetic and thermal responses to external and internal settings and the Sombrero software to evaluate the to evaluate the shading of surrounding buildings

Automating Large-Scale Simulation and Data Analysis with OMNeT++: Lession Learned and Future Perspectives

Simulation is widely adopted in the study of modern computer networks. In this context, OMNeT++ provides a set of very effective tools that span from the definition of the network, to the automation of simulation execution and quick result representation. However, as network models become more and more complex to cope with the evolution of network systems, the amount of simulation factors, the number of simulated nodes and the size of results grow consequently, leading to simulations with larger scale. In this work, we perform a critical analysis of the tools provided by OMNeT++ in case of such large-scale simulations. We then propose a unified and flexible software architecture to support simulation automation

Realizzazione di un applicazione per l\u27incremento della sicurezza dei dispositivi mobili

Abstract: Usually, operative systems in mobile devices do not offer native security solutions to protect sensible data of the users. To this aim, we show the development of an application for improving the security of mobile devices. This paper presents Data Defender, a security multiplatform application for PDAs and smartphones which improves the security of user data, like agendas, address books, personal contacts and files, by using criptographic techniques. Data Defender allows the creation of private areas and the capability to send/receive chiphered messages to/from mobile devices

A reinforcement learning-based link quality estimation strategy for RPL and its impact on topology management

Over the last few years, standardisation efforts are consolidating the role of the Routing Protocol for Low-Power and Lossy Networks (RPL) as the standard routing protocol for IPv6-based Wireless Sensor Networks (WSNs). Although many core functionalities are well defined, others are left implementation dependent. Among them, the definition of an efficient link-quality estimation (LQE) strategy is of paramount importance, as it influences significantly both the quality of the selected network routes and nodesâ\u80\u99 energy consumption. In this paper, we present RL-Probe, a novel strategy for link quality monitoring in RPL, which accurately measures link quality with minimal overhead and energy waste. To achieve this goal, RL-Probe leverages both synchronous and asynchronous monitoring schemes to maintain up-to-date information on link quality and to promptly react to sudden topology changes, e.g. due to mobility. Our solution relies on a reinforcement learning model to drive the monitoring procedures in order to minimise the overhead caused by active probing operations. The performance of the proposed solution is assessed by means of simulations and real experiments. Results demonstrated that RL-Probe helps in effectively improving packet loss rates, allowing nodes to promptly react to link quality variations as well as to link failures due to node mobility

Improving network formation in IEEE 802.15.4e DSME

Wireless Sensor and Actuator Networks are becoming attractive also for industrial applications, since recent standardization efforts have introduced significant improvement to reliability and deterministic communication delays. In this context, IEEE 802.15.4e is widely considered the major improvement, introducing many enhancements to the original IEEE 802.15.4 standard aimed at supporting critical applications. Among the new defined MAC protocols, Deterministic and Synchronous Multi-channel Extension (DSME) represents the most suitable option for applications with time-varying requirements. In this paper, an analysis of the IEEE 802.15.4 DSME MAC protocol during network formation is presented. The goal is to study the protocol performance and propose solutions to reduce the network formation time, improving energy and resource efficiency. To carry out the performance evaluation, DSME has been fully implemented in Contiki OS, an actual operating system for sensor nodes. The study has highlighted issues and inefficiencies in the network formation process, allowing to consequently propose effective solutions. In particular, it is proposed a set of guidelines for DSME configuration to the original MAC protocol that are proved to increase significantly the network formation efficiency