Print ISSN: 1811-9212

Online ISSN: 2617-3352

Keywords : Active Queue Management


H-infinity Based Active Queue Management Design for Congestion Control in Computer Networks†

Mr. Karam Samir Khalid; Assist. Prof. Dr. Hazem I. Ali

IRAQI JOURNAL OF COMPUTERS, COMMUNICATIONS, CONTROL AND SYSTEMS ENGINEERING, 2014, Volume 14, Issue 3, Pages 1-9

Abstract – In this paper the design of robust Active Queue Management (AQM) for
congestion control in computer networks is presented. The Ant Colony Optimization
(ACO) method is used to tune the parameters of PID controller subject to H-infinity
constraints. The nonlinear dynamic model for multiple TCP flows control is developed
based on fluid-flow theory. The designed controller provides good tracking performance
in the presence of wide range of system parameter uncertainty. NS2 package is used to
perform the nonlinear simulation of the system.

Design and Implementation of Adaptive Wavelet Network PID Controller for AQM in the TCP Network

Dr. Farooq Al- doraiee; Dr. Farooq Al- doraiee; dr.salih.al; uotechnology.edu.iq; qaraawi

IRAQI JOURNAL OF COMPUTERS, COMMUNICATIONS, CONTROL AND SYSTEMS ENGINEERING, 2013, Volume 13, Issue 1, Pages 9-17

Abstract – Internet represents a shared resource wherein users contend for the finite
network bandwidth. Contention among independent user demands can result in
congestion, which, in turn, leads to long queuing delays, packet losses or both.
Congestion control regulates the rate at which traffic sources inject packets into a
network to ensure high bandwidth utilization while avoiding network congestion. In the
current Internet, there are two mechanisms which deal with congestion; the end-to-end
mechanism which is achieved by the Transmission Control Protocol (TCP) and the
intermediate nodes algorithms such as Active Queue Management (AQM) in routers.
In this paper, a combined model of TCP and AQM (TCP/AQM) is formulated and
first simulated without a controller. The results show that it is unable to track the desired
queue size. So, to get better tracking performance, an adaptive PID controller based on
wavelet network (AWNPID) is used as AQM in the router queue. The non-adaptive PID
controller is also demonstrated, and its weakness to the network dynamic changes is
compared to the robustness of adaptive controller (AWNPID). The analytical results for
linearized TCP/AQM model are presented in MATLAB version 7.0.

FUZZY-GENETIC CONTROLLER FOR CONGESTION AVOIDANCE IN COMPUTER NETWORKS1

Prof. Dr. Mohammed Z. Al-Faiz; MIEEE; Assistant Lec. Ali M. Mahmood

IRAQI JOURNAL OF COMPUTERS, COMMUNICATIONS, CONTROL AND SYSTEMS ENGINEERING, 2011, Volume 11, Issue 2, Pages 20-27

Abstract:
In this paper a fuzzy proportional-Integral (FPI) controller is designed as an Active Queue Management (AQM) in internet routers to improve the performance of PI controller for congestion avoidance in computer networks. Firstly the parameters of FPI controller are selected by trial and error method, but to get the best controller parameters the Genetic Algorithm (GA) is used as an optimization method for tuning the FPI parameters. The analytical results for linearized TCP/AQM model are presented in MATLAB version 7.0. From the obtained results, a faster response time as well as the regulation of the output to a constant value by the designed FPI controller is clearly observed and it is noted that the FPI controller provides good tracking performance under different circumstances for congestion avoidance in computer networks.