Spectrum Sharing Games

Wednesday, June 29, 2005 - 9:30am - 10:30am
EE/CS 3-180
Randall Berry (Northwestern University)
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.