Resource Allocation in Heterogeneous Cognitive Radio Networks: A Cooperative Approach

Abstract

In cognitive radio networks (CRN), resources available for use are usually very limited. This is
generally because of the tight constraints by which the CRN operate. Of all the constraints, the most
critical one is the level of permissible interference to the primary users (PUs). Attempts to mitigate the
limiting effects of this constraint, thus achieving higher productivity is a current research focus and in
this work, cooperative diversity is investigated as a promising solution for this problem. Cooperative
diversity has the capability to achieve diversity gain for wireless networks. In the work therefore, the
possibility of and mechanism for achieving greater utility for the CRN when cooperative diversity is
incorporated are studied. To accomplish this, a resource allocation (RA) model is developed and
analyzed for the heterogeneous, cooperative CRN. In the model, during cooperation, a best relay is
selected to assist the secondary users (SUs) that have poor channel conditions. Overall, the cooperation
makes it feasible for virtually all the SUs to improve their transmission rates while still causing
minimal harm to the PUs. The results show a marked improvement in the RA performance of the CRN
when cooperation is employed in contrast to when the CRN operates only by direct communication.