Cognitive management frameworks and spectrum management strategies exploiting cognitive radio paradigm

Cognitive Radio (CR) paradigm represents an innovative solution to mitigate the spectrum scarcity problem by enabling Dynamic Spectrum Access (DSA), defined in order to conciliate the existing conflicts between the ever-increasing spectrum demand growth and the currently inefficient spectrum utilization. The basic idea of DSA is to provide proper solutions that allow sharing radio spectrum among several radio communication systems with sake of optimizing the overall spectrum utilization. This dissertation addressed the problem of modelling cognitive management frameworks that provide innovative strategies for spectrum management suitable to different scenarios and use cases in the context of DSA/CR Networks (CRNs). The first solution presented in this dissertation initially addressed the development of a framework that provides spectrum management strategies for Opportunistic Networks (ONs) defined as extended infrastructures created temporarily to serve specific regions following the policies dictated by the operator. The development of systems based on the CR paradigm to support the ONs is considered a key aspect to allow autonomous decisions and reconfiguration ability mechanisms because of the temporarily nature of these networks and the highly dynamic nature of the radio environment. Then, in order to expand the design of cognitive management frameworks providing spectrum management solutions that have applicability in a number of different scenarios and use cases, a cognitive management framework that exploits the Partially Observable Markov Decision Process (POMDP) concept has been proposed to combine the CR capabilities of radio environment awareness with a statistical characterization of the system dynamic. Finally, the framework based on POMDPs has been further extended with new functionalities able to characterize the environment dynamic through long-term predictions carried out exploiting the so-called belief vector. These frameworks as a whole aimed at demonstrating that a reliable characterization of the radio environment that combines awareness of its surrounding with a statistical evaluation of the system dynamics is able to guarantee an effcient utilization of the available spectrum resources. From a methodological point of view, the development and assessment of the proposed cognitive management frameworks and the corresponding spectrum management solutions involved analytical studies, system-level simulations and a real-time platform implementation. Overall, the research conducted in the context of this dissertation has revealed that proper cognitive management functionalities can be extremely beneficial to support spectrum management in a wide variety of scenarios and use cases.El paradigma de radio cognitiva (CR) representa una solución innovadora para mitigar el problema de escasez de los recursos radio, permitiendo el acceso dinámico al espectro (DSA), definido con el fin de conciliar los conflictos existentes entre el crecimiento de la demanda de espectro, cada vez mayor, y la utilización de los recursos radio actualmente ineficiente. La idea básica del DSA es proporcionar soluciones adecuadas que permitan compartir el espectro radioeléctrico entre varios sistemas de comunicaciones radio con el objetivo de optimizar la utilización general del espectro. Esta tesis doctoral aborda el problema de la modelización de marcos de gestión cognitiva que proporcionan estrategias innovadoras y adecuadas para la gestión del espectro en diferentes escenarios y casos de uso en el contexto de las redes de radio cognitiva (CRN). La primera solución que se presenta en esta tesis aborda inicialmente el desarrollo de un marco que ofrece estrategias de gestión del espectro para redes oportunistas (ONs) definidas como infraestructuras extendidas, creadas temporalmente para servir a regiones específicas siguiendo las políticas dictadas por el operador. Debido a la naturaleza temporal de estas redes y a la naturaleza altamente dinámica del entorno radio, el desarrollo de sistemas basados en el paradigma de CR para apoyar las ONs se considera un aspecto clave que permite decisiones autónomas y mecanismos de reconfiguración. Luego, con el fin de ampliar el diseño de los marcos de gestión cognitiva para proporcionar soluciones de gestión del espectro con aplicabilidad en una serie de diferentes escenarios y casos de uso, se ha propuesto un marco de gestión cognitiva que explota el concepto de Partially Observable Markov Decision Process (POMDP) para combinar las capacidades de conocimiento del entorno radio del CR, con una caracterización estadística de la dinámica del sistema. Finalmente, el marco basado en el POMDP se ha ampliado con nuevas funcionalidades capaces de caracterizar el entorno dinámico a través de predicciones a largo plazo llevadas a cabo explotando el concepto de belief vector. Estos marcos en su conjunto tienen el objetivo de demostrar que una caracterización fiable del entorno radio que combina el conocimiento de su entorno con una evaluación estadística de la dinámica del sistema, es capaz de garantizar una utilización eficiente de los recursos disponibles del espectro. Desde un punto de vista de la metodología, el desarrollo y la evaluación de los marcos de gestión cognitiva propuestos y las correspondientes soluciones de gestión del espectro han involucrado estudios analíticos, simulaciones y la implementación de una plataforma que permite evaluaciones en tiempo real. En general, la investigación llevada a cabo en el contexto de esta tesis doctoral ha revelado que funcionalidades adecuadas de gestión cognitiva pueden ser extremadamente eficientes para apoyar la gestión del espectro en una amplia variedad de escenarios y casos de estudio

Implementation of cognitive radio networks to evaluate spectrum management strategies in real-time

This paper illustrates a Universal Software Radio Peripheral (USRP)-based real-time testbed that is able to evaluate different spectrum management solutions that exploit the Cognitive Radio (CR) paradigm. The main objective of this testbed is to provide an accurate and realistic platform by which the performance of innovative spectrum management solutions for a wide set of scenarios and use cases in the context of Opportunistic Networks (ONs) and Cognitive Radio Networks (CRNs) can be entirely validated and assessed before their implementation in real systems. Real-time platforms are essential to carry out significant studies and to accurately assess the performance of innovative solutions before their implementation in the real world. This work provides a comprehensive description of the testbed, highlighting many interesting implementation details and illustrating its applicability for different studies that rely on the CR paradigm. Then, a particular application in a realistic Digital Home (DH) scenario is also illustrated, which allows demonstrating the effectiveness of the real-time testbed and assessing its practicality in terms of user-perceived end-to-end Quality of Experience (QoE) in a realistic environment.Peer ReviewedPostprint (author's final draft

QoS aware radio access technology selection framework in heterogeneous networks using SDN

This paper addresses the problem of radio access technology (RAT) selection in heterogeneous networks (HetNets). Current approaches rely on signal related metrics such as signal to interference plus noise ratio (SINR) for selection of the best network for the wireless user. However, such approaches do not take into account the quality of service (QoS) requirements of wireless users and therefore often do not connect them to the most suitable network. We propose a QoS aware RAT selection framework for HetNets based on software-defined networking (SDN). The proposed framework implements a RAT selection strategy that reflects QoS requirements of downlink flows using a metric called fittingness factor (FF). The framework relies on the flexibility and centralised nature of SDN to implement monitoring and RAT capacity assessment mechanisms that help in the realisation of the selection strategy. The simulation campaign illustrates the important gains achieved by our RAT selection framework in terms of data rates assigned to the wireless users, their satisfaction, and their quality of experience (QoE) compared against other state of the art RAT selection solutions

On the impact of the user terminal velocity on HSPA performance in MBMS multicast mode

Multimedia Broadcast/Multicast Services (MBMS), introduced in Universal Mobile Telecommunication System (UMTS), have the aim to allow transmissions from a single source entity to multiple destinations. From the radio perspective, MBMS foresees both pointto- point (PtP) and point-to-multipoint (PtM) transmission mode, supported by Dedicated, Common, and Shared channels. The High Speed Downlink Packet Access (HSDPA), analyzed in this paper, can guarantee a higher data rate through the introduction of High Speed Downlink Shared Channel (HS-DSCH), thus improving the performance of MBMS transmissions. The aim of this paper is to investigate the impact of the User Equipment (UE) speed on the maximum number of users that the HS-DSCH can support for MBMS applications. In particular, two different mobility profiles are taken into account (Pedestrian and Vehicular) and the obtained results are validated by considering different transmission power levels, cell coverage sizes and bit rates.Postprint (published version

On the optimization of power assignment to support multicast applications in HAP-based systems

The goal of this research work is to investigate how efficient High Altitude Platforms (HAPs) can be in supporting Multimedia Broadcast/Multicast Service (MBMS) in scenarios in which the terrestrial coverage is not available. Specifically, we propose to implement an effective Radio Resources Management (RRM) policy into the HAP Radio Network Controller (H-RNC), whose main aim is to increase the overall system capacity. The proposed technique achieves its goal by dynamically selecting the most efficient multicast transport channel in terms of power consumption, chosen amongst Dedicated Channel (DCH), Forward Access Channel (FACH), and High Speed Downlink Shared Channel (HS-DSCH). Advantages deriving from the joint use of channels belonging to different categories are exploited. Results achieved when using the proposed RRM are quite manifest and witnesses to the necessity of providing such a feature when deploying integrated HAP/Terrestrial platforms supporting MBMS services.Peer ReviewedPostprint (published version

On demonstrating spectrum selection functionality for opportunistic networks

This paper presents a testbed platform to demonstrate and validate spectrum opportunity identification and spectrum selection functionalities in Opportunistic Networks (ONs). The hardware component of the testbed is based on reconfigurable devices able to transmit and receive data at different operating frequencies, which are dynamically configured. The software component has been developed to perform the creation and maintenance of ON radio links, including spectrum opportunity identification and selection decision making as well as all the necessary signaling to support the ON operation. Therefore, the presented platform provides a powerful tool for testing different algorithms in real operational radio environments under various interference conditions, thus enabling to gain deeper insight into the performance of algorithmic solutions, beyond the purely theoretical analyses based on models and/or simulations. Results presented in the paper validate the implementation conducted at the laboratory and illustrate the reconfigurability capabilities of the ON links under different conditions.Peer ReviewedPostprint (published version

A dynamic access point allocation algorithm for dense wireless LANs using potential game

This work introduces an innovative Access Point (AP) allocation algorithm for dense Wi-Fi networks, which relies on a centralised potential game developed in a Software-Defined Wireless Networking (SDWN)-based framework. The proposed strategy optimises the allocation of the Wi-Fi stations (STAs) to APs and allows their dynamic reallocation according to possible changes in the capacity of the Wi-Fi network. This paper illustrates the design of the proposed framework based on SDWN and the implementation of the potential game-based algorithm, which includes two possible strategies. The main novel contribution of this work is that the algorithm allows us to efficiently reallocate the STAs by considering external interference, which can negatively affect the capacities of the APs handled by the SDWN controller. Moreover, the paper provides a detailed performance analysis of the algorithm, which describes the significant improvements achieved with respect to the state of the art. Specifically, the results have been compared against the AP selection considered by the IEEE 802.11 standards and another centralised algorithm dealing with the same problem, in terms of the data bit rate provided to the STAs, their dissatisfaction and Quality of Experience (QoE). Finally, the paper analyses the trade-off between efficient performance and the computational complexity achieved by the strategies implemented in the proposed algorithm

THE CLINICAL AND FORENSIC ROLE OF CITOLOGY IN PTA AND PT1 BLADDER CANCER MONITORING. CASE STUDY REVISION FOR THE PERIOD 2008 – 2017.

Introduction: The Authors describe the results of a retrospective study that analyzes importance of a proper bladder cancer monitoring, comparing the use of the different methods available, both in terms of diagnostic delay and in terms of legal medical repercussions. Materials and methods: Using the database of the Pathological Anatomy Department of the Modena Polyclinic, we have isolated a series of 238 patients with histological diagnosis of bladder urothelial carcinoma in pTa and pT1 stages with an observational minimum time interval after first diagnosis of at least 5 years. The observational statistical analysis of the data stored was made through a statistical software (SPSS report 11.00 USA). Results: The results of the present study show how cytological screening, performed constantly with urine tests during early-stage monitoring of bladder tumors, can be a valid tool for the timely diagnosis of tumor stage evolution. Indeed positivity of the cytological examination can direct to a rapid diagnostic and therapeutic re-planning. Conclusion: It would be desirable to standardize the best screening strategies about bladder cancer. With a correct standardization, a valid reference could be obtained both from a clinical point of view, and for a correct legal medical evaluation in term of diagnostic delay and, consequently, reduction in the chance of survival

Validation platform implementation description – D5.2

Deliverable D5.2 del projecte OneFITPostprint (published version

Results analysis and validation - D5.3

Deliverable D5.3 del projecte OneFITPostprint (author’s final draft