LQG control design over lossy communication links

Magdi S. Mahmoud*, Nezar M. Alyazidi, Abdul Wahed A. Saif

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

7 Scopus citations


This paper investigates the problem of linear-quadratic Gaussian feedback control over unreliable communication channels with observation noise. We consider the problems of estimation and control under two different protocols. In one protocol, the transfer control protocol-like protocol, the estimation/control unit provides acknowledgments to successfully deliver the packets. In the other protocol, the user datagram protocol (UDP)-like protocol, no acknowledgments are permitted. We address the nonlinearity for the UDP protocol using the suboptimal approach. It is shown that there is a critical value at which the system becomes unstable. These unstable properties do not only depend on the rates of the control packets but also on the eigenvalues for the considered system. Simulation of two numerical examples is carried out in detail to illustrate the theoretical analysis.

Original languageEnglish
Pages (from-to)2309-2326
Number of pages18
JournalInternational Journal of Systems Science
Issue number11
StatePublished - 2 Nov 2014

Bibliographical note

Funding Information:
The authors would like to thank the associate editor and the reviewers for their constructive comments on their submissions. The authors would also like to thank the deanship for scientific research (DSR) at KFUPM for support through the research group project RG1105-1.


  • LQG problem
  • Network protocols
  • Packet dropouts
  • Unreliable communication links

ASJC Scopus subject areas

  • Control and Systems Engineering
  • Theoretical Computer Science
  • Computer Science Applications


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