Abstract

Many military and civil applications of a wireless sensor network
require the sensors to be aware of their positions. Such a
localization problem has been extensively studied in the literature,
in terms of both theoretical analysis on the localizability of a
sensor network and practical techniques for the actual positioning of
sensors. Missing from the existing work, however, is the localization
of sensors within a given period of time. In many practical
applications of wireless sensor networks, it is crucial to accomplish
the localization of sensors within a given time bound because (1) it
is on the critical time path - i.e., a sensor has to position itself
first before annotating the monitored data with geographical
information, and (2) the localization process in general requires
consider message exchanges between sensors, making the network more
likely to be detected by the enemy. We find that the traditional
definition of relative localization - i.e., a process which terminates
when all sensors obtain their locations in the same coordinate system
– is inappropriate for evaluating the actual efficiency of
localization in practice, the main reason being that part of the
localization process can be seamlessly integrated into subsequent
payload transmissions without incurring additional communication
overhead. To address this problem, we define a novel problem called
essential localization, and present the first study on the essential
localizability of a wireless sensor network within a given time bound.


Speaker Bio

Dr. Cheng's research interests lie at Mobile computing, Algorithm
design and the intersection areas of the two, with primary focus on
the problems that arise in the areas of wireless networking and
in-network information processing, such as localization, topology
control, and channel scheduling.  His research has been published in
premium networking conferences such as ACM Mobihoc, IEEE Infocom, IEEE
ICDCS and journals such as IEEE Transactions on Mobile Computing
(TMC).