Analysis of Preemption Systems and Applications in Cognitive Radio - 02/18/2011

Aylin Turhan

Title: Analysis of Preemption Systems and Applications in Cognitive Radio

Abstract: Commercially available wireless spectrum is scarce. The spectrum shortage is more apparent than before with the increasing number of smart phones and wireless applications. Furthermore, static spectrum allocation policies cause underutilization. In order to satisfy the needs of the market and use the spectrum more efficiently, Cognitive Radio (CR) proposes dynamic spectrum access. In other words, the spectrum becomes a shared environment between the Primary Users (PU) and the Secondary Users (SU) when the licence holder allows it. The system design must maximize the revenue from SUs while it must not degrade Quality of Service of the PUs. As a solution, preemption scheme is proposed to provide differentiated services to different classes of users. Using a 2D Markov Chain and preemptive policies, two preemption applications on cognitive radio are introduced in this talk. Firstly, we will analyze the performance measures of a parallel link loss network and identify the preemption rates with the related probabilities. Secondly, we will talk about control schemes such as admission control, preemption control, and systems that employ both admission and preemption control in a multi-class network. Then, we will try to find out which policy yields the maximum long run expected reward.

-- JiaxiJin - 10 Mar 2011