abstract

• In this work, the distributed power allocation problem in universal mobile telecommunication systems (UMTS) is studied under feedback signal-to-noise ratio (SNR) constraints. The sources of uncertainty are assumed to come from the quantization process and measurement noise in the closed-loop system. The power allocation problem is formulated as a reference tracking problem of a pre-defined signal to noise-interference ratio. First, the synthesis problem with SNR constraints is studied as a 2-norm minimization process, which is equivalent to an LQR optimization problem. The solution of the associated Riccati equation in the LQR formulation is completely characterized, resulting in a state-feedback law with a special redundant structure. This control law is re-written in a transfer function format, where it is obtained a simple control strategy which is dependant on the round-trip delay in the feedback system. In addition, the corresponding 2-norm closed-loop performance is also studied. Thus, the selection of the weight in the LQR problem establishes a compromise between robustness to quantization errors and noise, and tracking performance. Finally, the analytical results are validated through simulation by considering time-varying channel gains and quantization in the feedback information. © 2011 IEEE.

authors

• Campos Delgado Daniel Ulises
• Luna Rivera José Martín

publication date

• 2011-01-01

published in

• CCE 2011 - 2011 8th International Conference on Electrical Engineering, Computing Science and Automatic Control, Program and Abstract Book  Proceedings

keywords

• LQR control; Power control; quality of service; SNR restriction Analytical results; Closed-loop performance; Control laws; Control strategies; Distributed Power-Allocation; Feed back information; Feedback systems; LQR control; LQR problem; Measurement Noise; Optimization problems; Power allocations; Quantization errors; Reference-tracking; Round trip delay; Signal to noise; SNR restriction; Sources of uncertainty; Synthesis problems; Time varying channel; Tracking performance; Universal mobile telecommunication systems; Automation; Control; Control theory; Distributed computer systems; Electrical engineering; Linear control systems; Packet networks; Power control; Process control; Quality of service; Riccati equations; Signal to noise ratio; State feedback; Uncertainty analysis; Mobile telecommunication systems

Digital Object Identifier (DOI)

• 10.1109/ICEEE.2011.6106614

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