Wireless feedback and feedforward data flow control subject to rate saturation and uncertain delay

This study discusses wireless data flow controller design accounting for input signal saturation and an unknown delay. A main focus is to maintain a low real‐time computational complexity. This is motivated by a need to run a very large number of controllers in a single network node, e.g. in wireless 5G data flow control applications. Linear quadratic Gaussian design is therefore first applied to compute feedback and feedforward gains, for assumed nominal delays without accounting for the saturation that is caused by the one‐directional data flow. Gridding of design penalties, system parameters and delays are then used to pre‐compute and tabulate a subset of the ℒ 2 stability region by repeated evaluation of the Popov criterion. This step secures a second requirement of robust stability with respect to the uncertain feedback delay. The design is validated with simulation using a detailed model of a networked wireless data flow controller used in cellular communications.