AQM controller design for TCP networks based on a new control strategy

Kahe, G ; Sharif University of Technology | 2013

736 Viewed
  1. Type of Document: Article
  2. DOI: 10.1007/s11235-013-9859-y
  3. Publisher: Kluwer Academic Publishers , 2013
  4. Abstract:
  5. When the network suffers from congestion, the core or edge routers signal the incidence of congestion through the active queue management (AQM) to the sources. The time-varying nature of the network dynamics and the complex process of retuning the current AQM algorithms for different operating points necessitate the development of a new AQM algorithm. Since the non-minimum phase characteristics of the network dynamics restrict direct application of the proportional-integral-derivative (PID) controller, we propose a compensated PID controller based on a new control strategy addressing the phase-lag and restrictions caused by the delay. Based on the unstable internal dynamics caused by the non-minimum phase characteristics, a dynamic compensator is designed and a PID controller is then allowed to meet the desired performance objectives by specifying appropriate dynamics for the tracking error. Since the controller gains are obtained directly from the dynamic model, the designed controller does not require to be tuned over the system operating envelop. Moreover, simulation results using ns2 show improvements over previous works especially when the range of variation of delay and model parameters are drastic. Simplicity, low computational cost, self-tuning structure and yet considerable improvement in performance are exclusive features of the proposed AQM for the edge or core routers
  6. Keywords:
  7. Active queue management (AQM) ; Congestion control ; TCP network ; Complex networks ; Congestion control (communication) ; Dynamics ; Electric control equipment ; Proportional control systems ; Queueing networks ; Three term control systems ; Time varying networks ; Transmission control protocol ; Tuning ; Two term control systems ; Computational costs ; Control strategies ; Dynamic compensator ; Internal dynamics ; Performance objective ; Proportional integral derivative controllers ; TCP networks ; Controllers
  8. Source: Telecommunication Systems ; Volume 57, Issue 4 , December , 2013 , Pages 295-311 ; 10184864 (ISSN)
  9. URL: http://link.springer.com/article/10.1007%2Fs11235-013-9859-y