The cognitive radio network (CRN) has been regarded as a promising approach to enhance the spectrum utilization. It allows unlicensed secondary users (SUs) to opportunistically share unused spectrum bands with licensed primary users (PUs). Secondary users are forced to vacate the channel when the primary user (PU) starts communication on its licensed channel. The paper presents a spectrum assignment scheme for CRNs which allocates available channels to SUs in such a manner that tries to equalize the load on the channels. The failure of secondary users may reduce the channel utilization and unbalance the load on channels. To overcome the problem our paper presents a scheme to balance the load on channels and to increase the spectrum utilization by doing minimum reallocation of secondary users. When the secondary user recovers from failure then channel allocation done by the scheme either increases the spectrum utilization or decreases the load imbalance ratio or both.
Pareek, H., & Singh, A. K. (2015). Fault tolerant spectrum assignment in cognitive radio networks. In Procedia Computer Science (Vol. 46, pp. 1188–1195). Elsevier B.V. https://doi.org/10.1016/j.procs.2015.01.032