Toronto Networking Seminar

We first consider spectrum sharing problems for downlink OFDM-based cognitive radio networks. Specifically, we investigate the joint subchannel, rate and power allocation for secondary users which share, in a non-disruptive manner, some frequency bands with primary users using OFDM technology. We explicitly consider a maximum total power constraint at the Base-Station and the power constraint on each subchannel determined by distributed spectrum sensing. Two resource allocation scenarios with increasing dimensions and complexity are considered: resource allocation in one time slot (repeated over the frame) or in multiple time slots. We formulate these resource allocation problems as the maximization of the minimum user throughput. For online implementation, we propose fast and low complexity algorithms to solve the spectrum sharing problems in different network settings. Numerical results are then presented to illustrate the performance of the proposed heuristics and reveal several insights into network design. They show that our proposed heuristic can produce approximate solutions roughly within 90% of the optimal value. It is shown that performing resource allocation over multiple time slots as opposed to a single time slot can actually improve network performance significantly. We also quantify the gains of using interference control instead of interference avoidance for spectrum sharing between primary and secondary networks.

We then discuss different generalizations of the above problems.

This work was done in collaboration with Dr. Long Le, Prof. Patrick Mitran and Prof. Andre Girard

Educated in France and in the USA, Dr. Rosenberg has worked in several countries including USA, UK, Canada, France and India. In particular, she worked for Nortel Networks in the UK, AT&T Bell Laboratories in the USA, Alcatel in France and taught at Purdue University (USA) and Ecole Polytechnique of Montreal (Canada).

In 2004, Dr. Rosenberg joined the Department of Electrical and Computer Engineering at the University of Waterloo where she holds a University Research Chair. From September 2004 to August 2007, she was the Chair of her Department.

Her research interests are broadly in networking with currently an emphasis in wireless networking and in traffic engineering (Quality of Service, Network Design, and Routing). She has authored over 100 papers and has been awarded eight patents in the USA. Since 2007, she is on the Scientific Board of France-Telecom (Orange), one of the largest telecommunications operators in the world.