Optimal Admission Control of Secondary Users in Preemptive Cognitive Radio Networks - 07/15/2011

Aylin Turhan

Title: Optimal Admission Control of Secondary Users in Preemptive Cognitive Radio Networks

Abstract: We study optimal admission control of secondary users (SUs) in cognitive radio(CR) networks in presence of preemption. In our model, when a primary user (PU) arrives to the system and finds all the channels busy, it preempts an SU unless all the customers in the system are PUs. We apply admission control on the SUs only. The service time is exponential and is indifferent to class type. Using dynamic programming, we find the optimal admission control policy that maximizes the total expected alpha-discounted revenue over finite and infinite horizon as well as the long run average revenue. As our major contribution, we show that the optimal admission control of the SUs depends only on the total number of customers in the system and is of threshold type (i.e. it does not depend on the number of PUs and SUs in the system individually.). Therefore, although the system is modeled as a two-dimensional Markov chain, our findings allow simple and efficient computation of the optimal control policy.

-- JiaxiJin - 22 Jul 2011