Cognitive Radio Networks (CRNs) are a key technology suggested to be part of 4G and
beyond. The fundamental concept is to let Secondary Users (SUs) have temporal free
access to spectrum bands not occupied by Primary Users (PUs). Since SUs are not allowed
to cause harmful interference to PUs, SUs need to select the most available spectrum bands
for access, also known as spectrum decision [1]. By performing spectrum sensing, SUs can
learn the characteristics of parameters, eg, received signal strength, interference, path loss …

Cognitive radio (CR) systems can enhance the licensed spectrum efficiency by finding and
allocating the underutilized channels of the primary users to the secondary users. After
scanning a wide range of spectrum. A general CR system needs to utilize all the available
channels of various bandwidths. Whenever the active primary users appear, the secondary
users shall return the borrowed channels, causing interruption even during a transmission
period. The behavior of changing the operating channels is called hopping mode in this …