2,180 research outputs found
Optimal jamming of wireless localization systems
In this study, optimal jamming of wireless localization systems is investigated. Two optimal power allocation schemes are proposed for jammer nodes in the presence of total and peak power constraints. In the first scheme, power is allocated to jammer nodes in order to maximize the average Cramér-Rao lower bound (CRLB) of target nodes whereas in the second scheme the power allocation is performed for the aim of maximizing the minimum CRLB of target nodes. Both schemes are formulated as linear programs, and a closed-form expression is obtained for the first scheme. Also, the full total power utilization property is specified for the second scheme. Simulation results are presented to investigate performance of the proposed schemes. © 2015 IEEE
Multi-stage Antenna Selection for Adaptive Beamforming in MIMO Arrays
Increasing the number of transmit and receive elements in
multiple-input-multiple-output (MIMO) antenna arrays imposes a substantial
increase in hardware and computational costs. We mitigate this problem by
employing a reconfigurable MIMO array where large transmit and receive arrays
are multiplexed in a smaller set of k baseband signals. We consider four stages
for the MIMO array configuration and propose four different selection
strategies to offer dimensionality reduction in post-processing and achieve
hardware cost reduction in digital signal processing (DSP) and radio-frequency
(RF) stages. We define the problem as a determinant maximization and develop a
unified formulation to decouple the joint problem and select antennas/elements
in various stages in one integrated problem. We then analyze the performance of
the proposed selection approaches and prove that, in terms of the output SINR,
a joint transmit-receive selection method performs best followed by
matched-filter, hybrid and factored selection methods. The theoretical results
are validated numerically, demonstrating that all methods allow an excellent
trade-off between performance and cost.Comment: Submitted for publicatio
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