Further results on exponential stability of linear discrete-time systems with time-varying delay

This note addresses the exponential stability problem of a class of discrete-time systems with interval time-varying delay. Based on the Lyapunov-Krasovskii method, a set of appropriate Lyapunov-Krasovskii functionals, containing an augmented vector and some triple summation terms is first proposed. By utilizing the combination of the reciprocally convex approach and the delay-decomposition technique, improved delay-dependent conditions for exponential stability of the system are derived in terms of linear matrix inequalities (LMIs). Numerical examples are given to illustrate the effectiveness of the proposed approach.