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Presenter: Dong Zhang
Supervisor: Dr. Hong-Chuan Yang

Date: Fri, July 27, 2012
Time: 11:00:00 - 00:00:00
Place: EOW 430

ABSTRACT

ABSTRACT:

Most of the cognitive radio (CR)-related research has focused on scenarios where a secondary system operates in the presence of a single primary communication system. In this work, we extend the study of a single-cell scenario to a more practical scenario where the secondary system is subjected to two independent primary users (PU). In particular, we investigate the performance of a secondary system operating in an interweaving fashion to explore the spectrum of opportunities. Under the assumption of the Poison traffic model for PU activities, we apply the Markov chain model to first determine the system parameters for combined PUs activities, and then characterize the dynamics of the spectrum opportunities for a secondary user (SU) for both single- and multiple-channel access. To fully investigate the proposed system, we also consider some possible drawbacks and provide corresponding solutions. We derive the exact mathematical expressions for the performance metrics, including average waiting time and average service time of the SU transmission. To enrich the performance analysis, other performance metrics, such as average throughput and collision frequency/ratio are also presented. Through selected numerical examples, we examine the effect of different operation parameters on the SU system performance. We believe that those analytical results can help predict which types of SU applications can be supported under certain practical PU activities.