A disturbance rejection and data rate trade-off in networked data flow control. (May 2019)

• Record Type: Journal Article
• Authors: Wigren, Torbjörn
• Is Part Of: European journal of control. Volume 47(2019)
• Page Start: 1
• Page End: 10
• Publication Date: 2019-05
• Subjects: Delay -- Disturbance rejection -- Data flow control -- Networked control -- Saturation -- Stability; Control theory -- Periodicals; Automatic control -- Periodicals; Automatic control -- Mathematics -- Periodicals; Electronic journals; 629.805
• DOI: 10.1016/j.ejcon.2018.07.001
• Languages: English
• ISSNs: 0947-3580

Abstract

Abstract: The paper discusses a trade-off between the steady state disturbance rejection performance and the achievable end to end data rate of a non-linear networked data flow control system. The control system is subject to delay and saturation, caused by the interface delays and the one-directional data flow. The trade-off is derived from a requirement of global L 2 -stability, in the limit where the loop delay tends to infinity. More specifically, it is proved that when the product of the steady state disturbance rejection ratio and a data flow discard rate is lower than 1/2, then the Popov inequality prevents L 2 -stability to be proved. A numerical study is presented, using a networked wireless data flow controller suitable for regulation of the transmission buffer data volumes in fifth generation base stations. The numerical results support the derived trade-off and show that in the studied special case the Popov criterion provides a tight prediction of the L 2 -stability limit. The numerical results also quantify the conservativeness of the asymptotic trade-off.