A NEW CHANNEL ASSIGNMENT METHOD IN COGNITIVE RADIO SYSTEM

In this paper, a novel method to estimate the unsuccessful probability is proposed by combining the unnecessary probability and the blocking probability. The Unnecessary probability is the probability when the mobile node is unnecessarily handed over and the blocking probability is the one when the network is not able to assign the channel to the mobile now. A new design of new channel assignment method for cognitive radio system is presented. The first fit method and the random assignment methods are also implemented for the cognitive radio application as a baseline. The PU and SU call blocking are modeled for all the three methods. It is shown that advantages of first fit method and the random assignment methods are combined into the new method, namely, selective assignment method. Simulation are conducted for the various network parameters like number of channels, number of links, load on each link, percentage of the PU versus SU calls etc. It is shown that selective assignment method yields better results than that of the first fit method and the random assignment methods. Finally, the blocking probabilities are combined with the unnecessary handover probabilities of a three-node network to determine the unsuccessful handover probabilities of the first fit, random assignment and selective assignment methods.