PhD Thesis Proposal Defence


"The Impact of Radio Signal Strength on the Design of Wireless Sensor
Networks"

by

Mr. Jian Ma


Abstract:

Radio signal strength (RSS) is an attractive property since it can be
obtained without additional hardware. Based on various signal propagation
models that describe the relationship between RSS and distance, RSS can be
employed in network connectivity, localization, and link quality issues.
However, the deterministic propagation models, in which RSS is only
determined by distance, are far from reality. We carefully design a series
of experiments using MICA2 nodes in real environments to investigate the
parameters besides distance--frequency, variation of transceivers, antenna
orientation, battery voltage, temporal-spatial properties of environment,
and environmental dynamics. All the parameters contribute to high RSS
irregularity, which makes a great challenge to the design of localization
and topology control algorithms in wireless sensor networks. RSS-based
localization, which computes inter-node distances from RSS measurements,
needs to recover significant errors in distance estimation. Rather than
static links with just on or off states, topology control algorithms have
to handle dynamic links with changing link qualities.

We propose some preliminary results for the two problems. We derive the
log-normal error model for RSS-based distance estimation and find out that
the popular noisy disk error model always underestimates distance error. A
quality-based localization algorithm is further given to cope with the
distance estimation errors. We also propose a series of energy-efficient
topology control algorithms, which are resilient to dynamic topology
changes.


Date:     		Friday, 15 December 2006

Time:                   10:00a.m.-12:00noon

Venue:                  Room 1504
			lifts 25-26

Committee Members:      Prof. Lionel Ni (Supervisor)
                        Dr. Yunhao Liu (Chairperson)
			Dr. Qiong Luo
			Dr. Qian Zhang


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