Analytical Framework for Throughput Evaluation of Practical Opportunistic Spectrum Access Networks - Cross-layer Approach

Jihoon Park
Advisor: Jihoon Park

Thursday, August 12, 2010 at 8:00am
Engr IV Maxwell Room 57-124

Abstract:

Opportunistic Spectrum Access (OSA) network operates on a spectrum that is already assigned to primary users (PU) in order to overcome spectrum scarcity problem. OSA system detects available PU spectrum and utilize it efficiently for data transmission.

In this thesis, we develop an analytical framework to evaluate system throughput of OSA network models. We decompose spectrum sensing and resource utilization strategies into layers, such as radio, physical and medium access control layers (MAC). Then, capturing interaction between those layers the developed analytical framework is able to evaluate the interplay between spectrum sensing and resource utilization. For example, it allows to assess the effect of the PU spectrum sensing efficiency on the performance of certain resource utilization schemes.

First, we present the analysis of the OSA ad hoc network. We consider various combinations of collaborative spectrum sensing and multichannel data MAC protocol abstractions. By comparing and optimizing different design combinations we show that it is generally better to buffer preempted SU connections than to switch them to PU vacant channels. Second, we apply the developed framework to the centralized network, where more complex and efficient communication protocols, e.g. OFDMA and two-stage sensing, are possible. From the analysis we conclude that for the case when large number of PUs operates with high activity, Opportunistic Spectrum OFDMA with subchannel notching and channel bonding could provide almost seven times higher throughput than the design without those options enabled.

In summary, we propose a general analytical framework which can provide comprehensive throughput evaluation for specific and practical design options of sensing and data MAC of OSA network. Conclusively, for any new technology of OSA network, we can use the developed framework to evaluate the throughput and present guidelines for the system design.

Biography:

Jihoon Park received his M.S. and B.S. in Electrical Engineering from Sogang University, Seoul, Korea in 1998 and 1996, respectively. After graduating, he worked at the mobile communications division of Samsung Electronics, Seoul, Korea. As a member of mobile terminal R&D team, he developed software for more than twenty commercial Samsung cell phones, including the world's first IS-2000 cell phone and the first Korean WCDMA cell phone. Since 2005 he has been pursuing his graduate studies at University of California Los Angeles. His current research focuses on the cross-layer modeling methods of practical Opportunistic Spectrum Access networks.