Opportunistic Spectrum Access in LTE-Advanced networks

Abstract

[ES] Esta tesina tiene como objetivo investigar, estudiar y desarrollar una solución para el acceso oportunista al espectro no licenciado en sistemas LTE. La solución propuesta apusta por la implementación de un coordinador que decida, dada la ubicación del usuario y el estado de sus interferencias, que recursos no licenciados tiene disponibles.

[EN] Long Term Evolution Advanced (LTE-A) has emerged as a promising mobile broadband access technology to cope with the increasing demand of traffic in wireless networks. However, the higher spectral efficiency of LTE-A is not enough without a better management of the scarce and overcrowded electromagnetic spectrum. Cognitive Radio (CR) has been proposed as a feasible solution to the problem of spectrum scarcity. Among all the mechanisms provided by CR, the Opportunistic Spectrum Access (OSA) aims at making opportunistic use of certain licensed bands whenever the primary system is not affected. This operation requires spectral awareness in order to avoid interferences with licensed systems. In spite of having some spectrum sensing mechanisms, LTE-A technology lacks other tools that are needed in order to improve the knowledge of the radio environment. In this framework, this Master Thesis studies the implementation of a Geo-located Data Base (Geo-DB) that collects the location of free pieces of spectrum available for OSA, based on a cooperative channel-state declaration. Moreover, the potential benefit of this LTE-compliant OSA solution is evaluated using a calibrated simulation tool. The results allow us to optimally configure the system and show that the proposed opportunistic system is able to significantly improve its performance with the available bandwidth.