Comments and improved results on “ filtering for discrete-time systems with randomly varying sensor delays”

This note points out some errors in the main results of Zhou and Feng [Zhou, S., & Feng, G. (2008). H ∞ filtering for discrete-time systems with randomly varying sensor delays. Automatica, 44 (7), 1918–1922] and presents the corrected versions of these results. Furthermore, an improved method, which is less conservative than that of Zhou and Feng, is proposed to solve the same problem discussed in the commented paper. A numerical example demonstrates the effectiveness of the proposed method.