5g mobile communications systems

Un sistema mobile di comunicazione è un sistema di telecomunicazioni in cui è possibile mantenere la connessione o legame tra due o più utenti, anche nelle situazioni di mobilità totale o parziale degli stessi utenti. I sistemi radiomobili si stanno evolvendo dalla creazione del 1G (prima generazione) al 4G (quarta generazione). I telefoni di ogni generazione si differenziano in quattro aspetti principali : accesso radio, velocità di trasmissione dati, larghezza di banda e sistemi di commutazione. In questa tesi si affronta il tema dei sistemi 5G , negli ambienti terrestri e satellitari , in quanto sono l'ultima evoluzione dei sistemi mobili . Si introduce il passaggio dalla prima alla connessione di quarta generazione , al fine di capire perché 5G sta per cambiare la nostra vita . Quello che mi colpisce è il sito italiano www.Repubblica.it che dice : " con la nuova generazione 5 possiamo affidare le intere porzioni nette di vita". La tecnologia cellulare , infatti , ha cambiato radicalmente la nostra società e il nostro modo di comunicare . In primo luogo è cambiata la telefonia vocale , per poi trasferirsi all' accesso dati , applicazioni e servizi. Tuttavia , Internet non è stato ancora pienamente sfruttato dai sistemi cellulari. Con l'avvento del 5G avremo l'opportunità di scavalcare le capacità attuali di Internet . Il sistema di comunicazione di quinta generazione è visto come la rete wireless reale , in grado di supportare applicazioni web wireless a livello mondiale ( wwww ). Ci sono due punti di vista dei sistemi 5G : evolutivo e rivoluzionario. Dal punto di vista evolutivo, i sistemi 5G saranno in grado di supportare wwww permettendo una rete altamente flessibile come un Adhoc rete wireless dinamica ( DAWN ) . In questa visione tecnologie avanzate, tra cui antenna intelligente e modulazione flessibile , sono le chiavi per ottimizzare le reti wireless ad hoc. Dal punto di vista rivoluzionario, i sistemi 5G dovrebbe essere una tecnologia intelligente in grado di interconnettere tutto il mondo senza limiti . Un esempio di applicazione potrebbe essere un robot wireless con intelligenza artificiale .

Connectivity management and dynamic context grouping in mobile heterogenous systems

In the last 10 years the number of mobile devices has grown rapidly. Each person usually brings at least two personal devices and researchers says that in a near future this number could raise up to ten devices per person. Moreover, all the devices are becoming more integrated to our life than in the past, therefore the amount of data exchanged increases accordingly to the improvement of people's lifestyle. This is what researchers call Internet of Things. Thus, in the future there will be more than 60 billions of nodes and the current infrastructure is not ready to keep track of all the exchanges of data between them. Therefore, infrastructure improvements have been proposed in the last years, like MobileIP and HIP in order to facilitate the exchange of packets in mobility, however none of them have been optimized for the purpose. In the last years, researchers from Mid Sweden University created The MediaSense Framework. Initially, this framework was based on the Chord protocol in order to route packets in a big network, but the most important change has been the introduction of PGrids in order to create the Overlay and the persistence. Thanks to this technology, a lookup in the trie takes up to 0.5*log(N), where N is the total number of nodes in the network. This result could be improved by further optimizations on the management of the nodes, for example by the dynamic creation of groups of nodes. Moreover, since the nodes move, an underlaying support for connectivity management is needed. SCTP has been selected as one of the most promising upcoming standards for simultaneous multiple connection's management.

Simulation of visible light communications in vehicular networks

The rapid development in the field of lighting and illumination allows low energy consumption and a rapid growth in the use, and development of solid-state sources. As the efficiency of these devices increases and their cost decreases there are predictions that they will become the dominant source for general illumination in the short term. The objective of this thesis is to study, through extensive simulations in realistic scenarios, the feasibility and exploitation of visible light communication (VLC) for vehicular ad hoc networks (VANETs) applications. A brief introduction will introduce the new scenario of smart cities in which visible light communication will become a fundamental enabling technology for the future communication systems. Specifically, this thesis focus on the acquisition of several, frequent, and small data packets from vehicles, exploited as sensors of the environment. The use of vehicles as sensors is a new paradigm to enable an efficient environment monitoring and an improved traffic management. In most cases, the sensed information must be collected at a remote control centre and one of the most challenging aspects is the uplink acquisition of data from vehicles. My thesis discusses the opportunity to take advantage of short range vehicle-to-vehicle (V2V) and vehicle-to-roadside (V2R) communications to offload the cellular networks. More specifically, it discusses the system design and assesses the obtainable cellular resource saving, by considering the impact of the percentage of vehicles equipped with short range communication devices, of the number of deployed road side units, and of the adopted routing protocol. When short range communications are concerned, WAVE/IEEE 802.11p is considered as standard for VANETs. Its use together with VLC will be considered in urban vehicular scenarios to let vehicles communicate without involving the cellular network. The study is conducted by simulation, considering both a simulation platform (SHINE, simulation platform for heterogeneous interworking networks) developed within the Wireless communication Laboratory (Wilab) of the University of Bologna and CNR, and network simulator (NS3). trying to realistically represent all the wireless network communication aspects. Specifically, simulation of vehicular system was performed and introduced in ns-3, creating a new module for the simulator. This module will help to study VLC applications in VANETs. Final observations would enhance and encourage potential research in the area and optimize performance of VLC systems applications in the future.