Supported by NILS Science and Sustainability (ES07) under EEA Grants. “Supported by a grant from Iceland, Liechtenstein and Norway through the EEA Financial Mechanism. Operated by Universidad Complutense de Madrid”

Reference: 014-ABEL-CM-2013
Principal investigator (PI): Dr. Joaquín Olivares, University of Córdoba
Partners: University of Córdoba (España); The Intervention Centre, Oslo University Hospital (Noruega)
Dates: 04/15/2014 – 11/30/2015

Most of the hospital devices behave in a highly synchronous, thus highly predictable, way. Besides, the programming of these devices is known to the network designers and the time constraints of the processes associated to each of the sampled processes are known in advance.
This allows establishing in advance the deadline of each sampled signal, which, together with their respective semantics provides a priority value. Thorugh the use of distributed mechanisms, it is possible to apply priority-based resource allocation techniques, which would allow for the effective reservation of time slots to higher-priority nodes, and informing other nodes that no data should be sent in such slot. Based on the existence of multiple communication channels and with the use of CR, it is possible to extend this mechanism, allowing several priority nodes to overlap their transmissions of data in the same time slots by reallocating them to different channels.
We propose the development of a distributed system that allows, through the use of dynamic priority allocation for reservation of shared resource, the effective temporal management of the communication channel supported by Cognitive Radio.
For the correct operation of such mechanism, a very accurate time synchronization system is necessary, so that all involved nodes have the same temporal value and with no differences in the local time in each of them.

Research results:
– Multiplicative composition of clock-skew components for improving time synchronisation
JM Castillo-Secilla, F León, J Olivares, JM Palomares
Electronics Letters 51 (13), 991-993. 2015
– SnifferWSNTOS: Software implementation for multi-channel IEEE 802.15.4 sniffer.
M Sánchez-Polonio, J. Olivares, JM Palomares, F León, JM Castillo-Secilla, A Cubero.
VI Jornadas de Computación Empotrada. 49-56. 2015