A Software Radio Implementation of Centralized MAC Protocol for Cognitive Radio Networks

In the past decade the cognitive radio paradigm has received great attention from academia and industry as a promising approach to solve the spectrum shortage problem. In spite of the intense research activity in the field of cognitive radio, we still register a limited number of network implementations based upon the cognitive radio principles. In this work we present the design and implementation of a proprietary medium access control protocol that we have conjectured using ECMA-392 standard as reference. In the proposed design, the network uses an out-of-band cognitive control channel (CCC) for network management operations. The main contributions of this paper are: (1) a working prototype of a centralized cognitive network implemented in the platform provided by the universal software radio peripheral and GNU Radio software; (2) the presentation of significant data acquired during the field test of our prototype such as average network reconfiguration delay when the CCC is jammed by the primary user and the capability of the cognitive network to reconstruct channel occupancy/vacancy by means of distributed spectrum sensing. The prototype has been designed to operate in the 375–445 MHz frequency bands for a potential application in public safety ad-hoc networks.