A Multichannel Allocation Strategy Based on Preemption Threshold and Preemption Probability in Cognitive Radio Networks

Table 1

Steps to obtain the best preemption probability through SOA.

Step 1	Initialize the number of individuals , change regulator , spiral shape control factors and , maximum number of iterations , lower bound of the preemption probability variance scope , and upper bound of the preemption probability variance scope
Step 2	Set the initial iteration number to 0, and set a random preemption probability for each individual . The value satisfies
Step 3	The system utility of each individual under the corresponding preemption probability is calculated by equation (36)
Step 4	Calculate and record the current optimal system utility and the corresponding preemption probability from individuals
Step 5	Compare and record the global optimal system utility and the corresponding preemption probability
Step 6	Update the preemption probability of each individual according to the following formulas:
	where generates the random number between [0,1] and generates the random number between
	Step 7	The amount of iterations is added by 1; if , go back to step 3; otherwise, output the optimum preemption probability