A Survey on Proactive and Reactive Channel Switching Techniques in Cognitive Radios

Channel switching in cognitive radio networks (CRN) enables the switching of cognitive radio users to the idle channel for avoiding any disruption with the licensed users. The channel switching schemes provide an efficient utilization of the unused spectrum in a channel. In this survey paper, we have characterized the channel switching schemes into two main categories, proactive channel switching (PCS) and reactive channel switching (RCS). Proactive channel switching is based on predicting the channel first and then performing switching, whereas reactive channel switching is an on-demand switching method where switching request is made at the instant of channel sensing. There are some models based on which these switching schemes have been implemented. In the presented work, advantages and limitations of these schemes have been discussed for a better performance analysis.