• Seminario día 16 de Septiembre de 2011

Resumen:

Although Cognitive Radio principles were primarily defined for cellular environments, they can be applied to HF communications to use the available resources more efficiently. In this work we consider the legacy users as primary users and our stations using the HFDVL (HF Data+Voice Link) architecture (developed by IDeTIC and GAPS-UPM) as secondary users. Our stations must be able to increase the use of the HF band by detecting the presence of uncoordinated primary users and avoiding collisions with them.
A model of the primary user activity dynamics of the HF band is described in this presentation. This model is based on Hidden Markov Models that were trained with measurements of the 14 MHz amateur band. Also, it can be used to make short term predictions of the sojourn time of a primary user in the channel.