Discrete-time control systems
Spread Spectrum CDMA
Wireless Communications & Mobile Computing
A passivity approach to game-theoretic CDMA power control
Automatica (Journal of IFAC)
Robust Power Control for CDMA Cellular Communication Systems
IEEE Transactions on Signal Processing
Adaptive closed-loop power control with quantized feedback and loop filtering
IEEE Transactions on Wireless Communications
Power control of cellular radio systems via robust Smith prediction filter
IEEE Transactions on Wireless Communications
Variance minimization stochastic power control in CDMA systems
IEEE Transactions on Wireless Communications
Variable structure power control algorithm in mobile radio systems
IEEE Transactions on Wireless Communications
Cross-layer design for wireless networks
IEEE Communications Magazine
Cross-layer design: a survey and the road ahead
IEEE Communications Magazine
A software radio architecture for linear multiuser detection
IEEE Journal on Selected Areas in Communications
Dynamical effects of time delays and time delay compensation in power controlled DS-CDMA
IEEE Journal on Selected Areas in Communications
A framework for uplink power control in cellular radio systems
IEEE Journal on Selected Areas in Communications
Adaptive power control for wireless networks using multiple controllers and switching
IEEE Transactions on Neural Networks
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In this work, it is proposed a unified framework to design and analyze uplink distributed power control schemes over flat-fading channels from a control theory perspective. The effects of linear detectors and round trip delays are explicitly characterized in this study. First, the optimal solution to the power minimization problem under signal to interference-noise ratio (SINR) restrictions is reviewed, where sufficient conditions for its existence are presented that depends on the detection strategy. Four different linear detection schemes are studied in this work: Matched Filter, Decorrelator, MMSE and Projector. Specifically, two special cases are analyzed with respect to the spreading codes properties: uniform cross-correlation and orthogonal codes, and under both conditions an explicit expression for the central solution is obtained. Nevertheless, one drawback of the central solution is its lack of robustness against channel estimation errors, transport delays and noise. Hence, it is proposed closed-loop control laws with linear power assignment which are capable of provide robustness to these channel effects. It is then presented that under certain conditions, stable feedback loops can be obtained considering SINR quantification, transmission and processing delays, and the resulting closed-loop power solutions tend to the central ones. Finally, it is illustrated that the selection of the linear detectors does not affect the resulting closed-loop dynamics, but the uplink transmission power in steady-state. An exhaustive simulation evaluation is included to validate the mathematical analysis presented for open and closed-loop solutions.