Subband coding for networked control systems

We study a source coding method for Networked Control Systems (NCS’s) for SISO LTI plant models. To make efficient use of limited communication resources between controller and plant actuator, we develop a non-uniformly sampled subband coding NCS architecture which we design to minimize a bound on the tracking error variance caused by quantization effects. Our main contribution, in relation to earlier work on subband coding NCS’s, lies in that we allow each subband to be equipped with pre- and post-filters. To characterize optimal filters and to solve the subband bit-allocation problem, we model quantization effects via signal-to-noise ratio constraints and explicitly take into account the closed loop nature of signals. Simulation results verify that the resultant designs perform exceptionally well, even in non-idealized situations.