The advent of Machine-2-Machine communications (M2M), denoted in 3GPP as Machine Type Communications (MTC) and indicating both the direct link between two electronic devices (MTC devices) and the communication between an MTC device and an MTC server, pro duces a huge increment in the number of terminals connected to the network. Therefore, on MTC communication is growing a higher and higher interest among mobile network companies and equipment vendors. Smartphones, tablets, cameras, recent IoT devices are just a few examples of how many ways we have to connect to the network. A fundamental feature needed for an MTC communication is the low latency, necessary for demanding and critical services. Studies and researches are focused on improving the latency of devices studying the various steps of the connection and data transfer procedures. In this work, different ways to obtain a lower latency are studied working on the first step of the synchronization between the user and the network: the random access procedure. This procedure is first studied in all its steps, trying to find out at which points it is possible to increase performance. After a complete analysis of this procedure, different approaches in pro cessing the devices are discussed: an approach using different subsets of sequences based on the position of the users and approaches using different portions of the area to be pro cessed according to different random access strategies (e.g. exploiting different time slots). Results in terms of the average time for a device to complete the random access procedure are compared and conclusions on the most convenient approaches according to the scenario are discussed.
L'introduzione della comunicazione Machine-to-Machine (M2M), chiamata da 3GPP Machine Type Communications (MTC) e indicante sia il link diretto tra due dispositivi elettronici ("MTC device"), sia la comunicazione tra un dispositivo MTC con un server MTC, sta producendo un incredibile incremento nel numero di terminali connessi alla rete mobile. La comunicazione MTC sta pertanto facendo crescere un sempre maggior interesse tra le compagnie di reti mobili e tra i vari fornitori di servizi. Smartphones, tablets, cameras, dispositivi IoT, sono solo pochi esempi dei tanti modi che abbiamo per connetterci alla rete. Una fondamentale caratteristica per la comunicazione MTC in alcuni contesti applicativi è la bassa latenza. Studi e ricerche si concentrano sul miglioramento della latenza dei dispositivi, studiando i vari passaggi della procedura di connessione e di trasferimento dati. In questo lavoro sono stati studiati diversi metodi per ottenere una latenza sempre più bassa, lavorando sul primo step della sincronizzazione tra l'utente e la rete: la procedura di accesso casuale. Questa procedura è stata studiata in tutti i suoi passaggi, cercando di scoprire in quale punti è possibile focalizzarsi per migliorare le prestazioni. Dopo una completa analisi di questo procedimento, diversi approcci sono stati discussi: un approccio che usa porzioni differenti di sequenze in base alla particolare divisione dell' area di connessione e un approccio che associa diverse porzioni di area a diverse strategie di accesso (per es. usando diversi slot temporali). I risultati sono stati espressi in termini di tempo medio necessario a un dispositivo per completare la procedura di accesso casuale e le conclusioni riguardanti i migliori approcci da adottare in base alla situazione sono state ampiamente discusse.
Random access strategies for mobile systems
BROGGI, FEDERICO
2017/2018
Abstract
The advent of Machine-2-Machine communications (M2M), denoted in 3GPP as Machine Type Communications (MTC) and indicating both the direct link between two electronic devices (MTC devices) and the communication between an MTC device and an MTC server, pro duces a huge increment in the number of terminals connected to the network. Therefore, on MTC communication is growing a higher and higher interest among mobile network companies and equipment vendors. Smartphones, tablets, cameras, recent IoT devices are just a few examples of how many ways we have to connect to the network. A fundamental feature needed for an MTC communication is the low latency, necessary for demanding and critical services. Studies and researches are focused on improving the latency of devices studying the various steps of the connection and data transfer procedures. In this work, different ways to obtain a lower latency are studied working on the first step of the synchronization between the user and the network: the random access procedure. This procedure is first studied in all its steps, trying to find out at which points it is possible to increase performance. After a complete analysis of this procedure, different approaches in pro cessing the devices are discussed: an approach using different subsets of sequences based on the position of the users and approaches using different portions of the area to be pro cessed according to different random access strategies (e.g. exploiting different time slots). Results in terms of the average time for a device to complete the random access procedure are compared and conclusions on the most convenient approaches according to the scenario are discussed.| File | Dimensione | Formato | |
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https://hdl.handle.net/10589/147310