دانلود رایگان مقاله رویکرد کنترل برای رسیدن به عدالت نسبی در WLAN ها EDCA 802.11e

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 state-space 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.

6. Conclusions

This paper considers using a closed-loop control approach to achieve proportional fair allocation of station throughputs in a multipriority EDCA WLAN. The optimal station attempt probability that leads to proportional fairness is derived given the average delay deadline constraints of different ACs present in an WLAN. To achieve the desirable proportional fairness, a centralised adaptive control approach is proposed. The WLAN is represented as a discrete MIMO LTI state-space model. The LQI control is used to tune the CWmin value to the optimum. We have demonstrated using numerical results that the proposed control approach has high accuracy and fast convergence speed, and is adaptive to general network scenarios. To the best of our knowledge this might be the first detailed study of using a closedloop control approach to achieve proportional fairness amongst ACs in EDCA WLANs. The optimisation of controller parameters is not considered in this paper. We leave that for future work.