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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