# Toronto Networking Seminar

## Special Session on Samples from INFOCOM'10

A special session of the Toronto Networking Seminar will be held this week. Members of the University of Toronto will present a sampling of their papers published in INFOCOM'10.

Time: 2 pm, Friday, March 26
Location: BAB025 (Bahen Centre Basement)

--------
Talk #1:

Compressive Sensing Based Positioning Using RSS of WLAN Access Points

Presented by Ms. Chen Feng

The sparse nature of location finding problem makes the theory of compressive sensing desirable for indoor positioning in Wireless Local Area Networks (WLANs). In this paper, we address the received signal strength (RSS)-based localization problem in WLANs using the theory of compressive sensing (CS), which offers accurate recovery of sparse signals from a small number of measurements by solving an 1-minimization problem. A pre-processing procedure of orthogonalization is used to induce incoherence needed in the CS theory. In order to mitigate the effects of RSS variations due to channel impediments, the proposed positioning system consists of two steps: coarse localization by exploiting affinity propagation, and fine localization by the CS theory. In the fine localization stage, access point selection problem is studied to further increase the accuracy. We implement the positioning system on a WiFi-integrated mobile device (HP iPAQ hx4700 with Windows Mobile 2003 Pocket PC) to evaluate the performance. Experimental results indicate that the proposed system leads to substantial improvements on localization accuracy and complexity over the widely used traditional fingerprinting methods.

--------
Talk #2:

Optimal Control of Constrained Cognitive Radio Networks with Dynamic Population Size

We consider the problem of optimal control for throughput utility maximization in cognitive radio networks with dynamic user arrivals and departures. The cognitive radio network considered in this work consists of a number of heterogeneous sub-networks. These sub-networks may be power-constrained and are required to operate in such a way that the average total interference received on primary channels are kept below given thresholds. We develop a control policy that performs joint admission control and resource scheduling. Through Lyapunov optimization techniques, we show that the proposed policy achieves a utility performance within $O(\delta)$ of optimality for any positive $\delta$. We further show that this arbitrarily closeness to optimality comes at the price of having a delay that is $O(\frac{1}{\delta})$ in admitting users. We also propose constant factor approximations of the policy for distributed implementation.