Title page for ETD etd-08282002-141114

Type of Document

Master's Thesis

Author

He, Jian

Author's Email Address

jihe@vt.edu

URN

etd-08282002-141114

Title

Global Optimization of Transmitter Placement for Indoor Wireless Communication Systems

Degree

Master of Science

Department

Computer Science

Advisory Committee

Advisor Name	Title
Watson, Layne T.	Committee Chair
Ribbens, Calvin J.	Committee Member
Santos, Eunice E.	Committee Member

Keywords

bit error rate
direct search
DIRECT algorithm
global optimization
transmitter placement
dynamic data structures
power coverage

Date of Defense

2002-08-22

Availability

unrestricted

Abstract

The DIRECT (DIviding RECTangles) algorithm JONESJOTi, a variant of
Lipschitzian methods for bound constrained global optimization, has
been applied to the optimal transmitter placement for indoor wireless
systems. Power coverage and BER (bit error rate) are considered as
two criteria for optimizing locations of a specified number of
transmitters across the feasible region of the design space. The
performance of a DIRECT implementation in such applications depends
on the characteristics of the objective function, the problem
dimension, and the desired solution accuracy. Implementations with
static data structures often fail in practice because of unpredictable
memory requirements. This is especially critical in $S^4W$
(Site-Specific System Simulator for Wireless communication systems),
where the DIRECT optimization is just one small component connected
to a parallel 3D propagation ray tracing modeler running on a 200-node
Beowulf cluster of Linux workstations, and surrogate functions for a
WCDMA (wideband code division multiple access) simulator are also
used to estimate the channel performance. Any component failure of this
large computation would abort the entire design process. To make the
DIRECT global optimization algorithm efficient and robust, a set of
dynamic data structures is proposed here to balance the memory
requirements with execution time, while simultaneously adapting to
arbitrary problem size. The focus is on design issues of the dynamic data
structures, related memory management strategies, and application issues
of the DIRECT algorithm to the transmitter placement optimization for
wireless communication systems. Results for two indoor systems
are presented to demonstrate the effectiveness of the present work.

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