Fault Tolerant Spectrum Assignment in Cognitive Radio Networks

Abstract

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.

Cross‐layer perspective for channel assignment in cognitive radio networks: A survey

“…To reduce the interference with the PU, it is very important that channel is sensed perfectly by the SU . A cooperative sensing‐based channel assignment for multichannel CRN is proposed in Wang et al Connectivity and reliability : In this kind of issues, channel is assigned to improve overall connectivity in the network, whereas reliability deals with the fault tolerance of network such that in case of link failure, overall network performance should not be degraded Fairness : Many existing works focused on fairness in the channel assignment such that starvation to any SU could be avoided.…”

“…In this kind of issues, channel is assigned to improve overall connectivity in the network, 18,19 whereas reliability deals with the fault tolerance of network such that in case of link failure, overall network performance should not be degraded. 20…”