Spectrum Sharing Games

In wireless networks a key consideration is how to mitigate interference among multiple users in a given spectrum band. This is especially true in unlicensed or open bands, where users may be deployed without any centralized frequency planning or control. In this talk, we describe some simple mathematical models for sharing a given spectrum band. We discuss both a case where a spectrum manager controls access and a case where there is no manager and users implement a distributed algorithm to manage access. In the first case, we describe an auction mechanisms where the users bid for spectrum access. We model this auction as a game and characterize the equilibrium. In the second case, we discuss a distributed algorithm, in which users announce "price" signals which indicate the cost of interference to them. We relate this algorithm to a "fictitious" game, which in certain cases is supermodular. This relation is used to characterize the algorithms convergence. Extensions to multi-channel networks will also be discussed, where users can allocate their power over multiple frequency bands, as in a OFDM system. (Joint work with Michael Honig and Jianwei Huang at Northwestern.)
Randall Berry received the B.S. degree in Electrical Engineering from the University of Missouri-Rolla in 1993 and the M.S. and PhD degrees in Electrical Engineering and Computer Science from the Massachusetts Institute of Technology in 1996 and 2000 respectively. He is currently an assistant professor in the Department of Electrical and Computer Engineering at Northwestern University. In 1998 he was on the technical staff at MIT Lincoln Laboratory in the Advanced Networks Group. His primary research interests include wireless communication, data networks, and information theory. He is the recipient of a 2003 NSF CAREER award and the Best Teacher award for the 2001/2002 academic year from the ECE Department at Northwestern University.