Transmission Power Control for Opportunistic QoS Provision in Wireless Networks

This paper proposes an automatic control framework to address the problem of distributed and opportunistic transmission power control in wireless communication networks. The proposed framework allows high flexibility on the quality of service (QoS) provision by exploiting the link quality variation. It associates a standard target tracking algorithm with a dynamic target QoS determined by a linear quadratic regulator (LQR) controller that induces an opportunistic behavior. Strict QoS requirements can also be fulfilled by choosing appropriately the weighting parameters of the LQR synthesis. To prevent performance degradation due to measurement uncertainties, robust solutions are developed. The proposed mixed H₂/H_∞ distributed power control combines the optimal H₂ control and the robust H_∞ control to obtain trade-off solutions. All developed algorithms present low computational complexity, and the mixed H₂/H_∞ distributed power control can operate as the pure H₂ control if the robust constraint is relaxed according to the choice of a single parameter. The performance of proposed algorithms is assessed through computer simulations.