Cognitive radio in HF communications: selective transmission and broadband acquisition

Abstract

In this Thesis, the application of cognitive radio principles is proposed to reduce the amount of collisions between HF users and to reduce the inefficient use of this band. The cycle of tasks that a cognitive radio should face can be divided into three main tasks: Observe, Learn, and Decide & Act. They represent the cycle from the spectrum acquisition to the selection of the best channel to transmit, according to the observed and learned activity of other users. A database of real measurements of the activity in the HF band is created in order to evaluate and validate the proposed cognitive techniques in this Thesis. This database contains wideband measurements of the power spectrum of the HF band.