Title page for ETD etd-05052003-171217

Type of Document

Master's Thesis

Author

Ballagh, Jason

Author's Email Address

jaballag@vt.edu

URN

etd-05052003-171217

Title

Bluetooth Frequency Hop Selection Kernel Impact on “Inter-Piconet” Interference

Degree

Master of Science

Department

Electrical and Computer Engineering

Advisory Committee

Advisor Name	Title
Sweeney, Dennis G.	Committee Chair
Baumann, William T.	Committee Member
Pratt, Timothy J.	Committee Member

Keywords

Synchronization
Hop selection kernel
Inter-piconet
Piconet
Bluetooth
Interference

Date of Defense

2003-04-29

Availability

unrestricted

Abstract

The Bluetooth wireless transmission standard provides a low-power data link between
electronic devices over relatively short ranges. These links, also known as piconets,
transmit using frequency hopping spread spectrum (FHSS) to send information over the
air. As more applications for Bluetooth technology become available, the number of
Bluetooth devices will continue to increase. With this increase in use, there will be a
decrease in performance that can be attributed to Bluetooth “inter-piconet” interference.
To date, very little has been published on the subject of inter-piconet interference.
Previous studies have derived mean packet error rates for an increase in the number of
piconets present. To come up with the mean rate, many papers make the assumption that
the probability of a Bluetooth device hopping to a channel is random. However, making
this assumption does not explain what happens in real time.

This research gives some insight into what really happens when multiple piconets are
interfering in real time. Bluetooth devices actually use a frequency hopping algorithm to
determine the hopping sequence. This algorithm has been implemented in software to
test various aspects of inter-piconet interference. Previous studies have shown that
synchronizing the clocks among neighboring piconets will result in an increase in
performance. This study shows that there are cases where synchronization alone will not
provide sufficient improvement. Experimental testing has been conducted to validate
some of the simulated results. Adjacent channel interference was observed during
experimentation. This contradicts previous research, which has assumed that adjacent
channel interference is insignificant.

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