Jammer placement algorithms for wireless localization systems
Author(s)
Advisor
Gezici, SinanDate
2016-07Publisher
Bilkent University
Language
English
Type
ThesisItem Usage Stats
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Abstract
The optimal jammer placement problem is proposed and analyzed for wireless
localization systems. In particular, the optimal location of a jammer node is obtained
by maximizing the minimum of the Cram´er-Rao lower bounds (CRLBs)
for a number of target nodes under location related constraints for the jammer
node. For scenarios with more than two target nodes, theoretical results are derived
to specify conditions under which the jammer node is located as close to
a certain target node as possible, or the optimal location of the jammer node is
determined by two of the target nodes. Also, explicit expressions are provided
for the optimal location of the jammer node in the presence of two target nodes.
In addition, in the absence of distance constraints for the jammer node, it is
proved, for scenarios with more than two target nodes, that the optimal jammer
location lies on the convex hull formed by the locations of the target nodes and
is determined by two or three of the target nodes, which have equalized CRLBs.
Numerical examples are presented to provide illustrations of the theoretical results
in different scenarios. Furthermore, an iterative algorithm is proposed for
numerically determining the optimal jammer location. At each iteration of the
algorithm, the jammer node is moved one step along a straight line with the purpose
of increasing the CRLB(s) of the target node(s) with the minimum CRLB in
the system. It is shown that the algorithm converges almost surely to the optimal
jammer location under certain conditions for an infinitesimally small step size in
the absence of location constraints for the jammer node. Simulations illustrate
the effectiveness of the proposed algorithm in finding the optimal jammer location
and its superiority in terms of the computational complexity compared to
the exhaustive search over all feasible locations.