on 03-06-2011
Prof. Gonzalo Seco©\Granados
Friday, June 3, 2011, 15h 30, Amphitheater EA1, Torre Norte
Abstract: Decomposition techniques apply the well©\known idea of divide©\and©\conquer to convex optimization problems, being primal and dual decomposition the two classical approaches. Although they achieve the goal of splitting the original program into several smaller problems (called the subproblems), these techniques exhibit in general slow speed of convergence and need user©\adjusted parameters.
In the signal processing and communication fields we usually deal with a variety of problems that exhibit certain coupling structures between the variables. In particular, we will focus on resource allocation problems, whose formulation is equivalent to the one found under the NUM framework and allows us to introduce QoS and cross©\layer information. We will argue how this formulation can be applied both to scheduling problems and to bandwidth©\on©\demand (BoD) systems, and we will review the application of primal and dual decompositions to these problems.
We will present the so©\called coupled©\decompositions method (CDM) that overcomes the drawbacks of the existing decompositions. It is derived after a careful observation of the information exchanged in the primal and dual decompositions, where one can realize that new schemes for information exchange are possible. The new method is interesting in both distributed and centralized implementations because it reduces the amount of signaling and provides a simple criterion to stop the iterations.
Finally, we will discuss the results obtained by applying the coupled©\decompositions method to three basic problems: classical water©\filling in Orthogonal Frequency Division Multiplexing (OFDM), fair Dynamic Bandwidth Allocation (DBA), and power allocation for cognitive radios.
Gonzalo Seco©\Granados received the Ph.D. degree in telecommunication engineering from Universitat Polit¨¨cnica de Catalunya (UPC), Barcelona, Spain, in 2000, and the M.B.A. degree from IESE ©\ University of Navarra, Barcelona, Spain, in 2002. During 2002©\2005, he was member of the technical staff with the RF Payload Division, European Space Research and Technology Center (ESTEC), European Space Agency, The Netherlands, where he was involved in the Galileo project. Since 2006, he has been an Associate Professor in the Department of Telecommunications and Systems Engineering, Universitat Aut¨°noma de Barcelona, Spain. Since March 2007, he is coordinator of the Telecommunications Engineering degree. Currently, he is Director of the Chair of Technology and Knowledge Transfer UAB Research Park©\Santander.