Interference Management in Cognitive Networks with Reactive Primary Users
Marco Levorato, USC.
Wednesday Nov 3. 2010
Most of the work on cognitive networks assumes independence between the transmission strategy of the secondary users and the stochastic process modeling the activity of the primary users. Nevertheless, in many scenarios of interest this assumption does not hold. In fact, fixed networking and transmission mechanisms may react to the activity of the secondary users, thus introducing correlation between secondary and primary users operations. For instance, if packet retransmission is implemented by the primary users, the transmission/interference strategy of the secondary users “modulates” the retransmission process of the primary users, thus influencing their future queue and packet service state.
In this talk, I discuss the stochastic models and control frameworks which we used to optimize secondary users' operations in this scenario, and the obtained optimal policies. Different from traditional white space-based frameworks, the strategy of the secondary users is mapped on a non-binary state space modeling primary users' protocols and queues. We show that, for a simple topology with a single secondary and a single primary user using a truncated ARQ protocol, the throughput-optimal transmission/interference strategy of the secondary user has a specific structure. In particular, interference from the secondary user is concentrated in the first transmissions of primary user's packets.
Marco Levorato (S'06, M'09) was born in Venice, Italy, in 1980. He obtained both the BE (Electronics and Telecommunications Engineering) and the ME (Telecommunications Engineering) summa cum laude from the University of Ferrara, Italy, in 2002 and 2005, respectively. In 2009, he received the PhD in Information Engineering from the University of Padova. He is currently a post doctorate researcher researcher at Stanford and the University of Southern California under the supervision of Prof. Andrea Goldsmith and Prof. Urbashi Mitra. He is author or co-author of 42 technical papers either published or accepted for publication in major IEEE and ACM journals and conferences.
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