### Optimization and Systems Theory Seminar

Friday, August 31, 2001, 11.00-12.00, Room 3721, Lindstedtsvägen 25

**Mikael Johansson **

Information Systems Laboratory

Stanford University

Stanford, California, USA

E-mail:
mikaelj@stanford.edu

####
Joint optimization of wireless networks and linear systems

In this talk we discuss the design of linear systems, such as
estimators or controllers, in which several signals are transmitted
over wireless communication links. We focus on finding the allocation
of communication resources, such as transmission powers, bandwidths,
or time-slot fractions, that yields the optimal system performance.
In the first part of the talk, we assume that the linear system is
fixed and address the problem of allocating communication resources to
optimize system performance. We show that for many channel models,
this problem is convex, hence readily solved. We describe a dual
decomposition method that exploits the problem structure, and show how
the method reduces to standard waterfilling techniques in problems
with only one coupling constraint. We briefly describe how integer
constraints on communication rates can be handled and give a bound on
how suboptimal these heuristics can be.

In the second part of the talk, we consider the problem of jointly
allocating communication resources and designing the linear system in
order to optimize the overall system performance. This problem is in
general not convex, but can be solved heuristically in a way that
exploits the problem structure and appears to work well in practice.

This talk is based on joint work with Lin Xiao, Haitham Hindi, Stephen
Boyd, and Andrea Goldsmith.

Calendar of seminars

*Last update: August 8, 2001 by
Anders Forsgren,
anders.forsgren@math.kth.se.
*