JOURNAL OF COMMUNICATIONS (JCM)
ISSN : 1796-2021
Volume : 4    Issue : 3    Date : April 2009

Accumulative Interference Modeling for Distributed Cognitive Radio Networks
Michael Timmers, Sofie Pollin, Antoine Dejonghe, Ahmad Bahai, Liesbet Van der Perre, and Francky Catthoor
Page(s): 175-185
Full Text:
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Abstract
A Cognitive Radio (CR) network should be able to sense its environment to adapt its communication so that it
can utilize unused licensed spectrum without interfering with incumbent users. Properly modeling the
expected interference from the entire CR network is therefore very important to effectively protect these
incumbent users. We model the accumulative interference generated from a large-scale CR network and
investigate how the CR network density affects the sensing requirements of the CRs to meet an interference
constraint. More specifically, our model considers the impact of discrete network topology, the impact of
imperfect sensing and the impact of collisions when the CR uses a distributed channel access scheme. We
then apply our model to a CR network based on the IEEE 802.11 standard. We show that the collisions
occurring frequently in these networks only have a small on the sensing requirements to protect the
incumbent network.

Index Terms
cognitive radio, opportunistic spectrum access, interference modeling, IEEE 802.11