A control theoretic approach to achieve proportional fairness in 802.11e EDCA WLANs

TL;DR

This paper introduces a control theoretic method using a Linear Quadratic Integral controller to dynamically achieve proportional fairness in EDCA WLANs, ensuring QoS and priority requirements with high accuracy and fast convergence.

Contribution

It presents the first closed-loop control system design for EDCA WLANs to attain proportional fairness through a centralized adaptive control approach.

Findings

High accuracy in fairness achievement

Fast convergence in various network scenarios

Effective dynamic adjustment of station attempt probabilities

Abstract

This paper considers proportional fairness amongst ACs in an EDCA WLAN for provision of distinct QoS requirements and priority parameters. A detailed theoretical analysis is provided to derive the optimal station attempt probability which leads to a proportional fair allocation of station throughputs. The desirable fairness can be achieved using a centralised adaptive control approach. This approach is based on multivariable statespace control theory and uses the Linear Quadratic Integral (LQI) controller to periodically update CWmin till the optimal fair point of operation. Performance evaluation demonstrates that the control approach has high accuracy performance and fast convergence speed for general network scenarios. To our knowledge this might be the first time that a closed-loop control system is designed for EDCA WLANs to achieve proportional fairness.