Systems Seminar

An Adaptive View of Timing and Synchronization in Telecommunication Systems

Prof. Bill Sethares
UW ECE Department

Abstract

Many of the standard tasks in telecommunication systems can be viewed as optimization problems, and these can often be solved using an adaptive (gradient) style iteration. This paper shows how the synchronization tasks of timing recovery and phase tracking can be stated and solved using iterative adaptive algorithms.

The talk begins by reviewing the relevant synchronization problems, then shows that the standard algorithms such as the phase locked loop and the `Costas loop' algorithm (and several others) can be viewed this way.

One of the more interesting theoretical issues comes from the incorporation of several different adaptive loops within one system. What are the interactions between the various adaptive subsystems, and how can the interactions be quantified? When is there a viable time-scale separation? We look at these broader questions by example, demonstrating that as the limits of performance of the system are increased, the interactions between the levels can increase. This underscores the need for a more comprehensive treatment at the system-wide level, rather than at the level of the individual adaptive subsystems.

A concrete application of the methods of analysis of adaptive algorithms leads to a new class of (blind, untrained) timing recovery algorithms that have some intriguing optimization properties.

Time and Place: Wed., Feb. 19, at 3:30 pm in 4610 Engr. Hall.

SYSTEMS SEMINAR WEB PAGE: http://www.cae.wisc.edu/~gubner/seminar/

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