Energy efficiency and quality of service optimization for constant bit rate real-time applications in 802.11 networks

In this paper, we propose a quality of service QoS-sensitive energy efficiency optimization mechanism for 802.11 networks on the basis of the dynamic and simultaneous adjustment of the content window W and retry attempts limit r of the media access control MAC sublayer. The use of both operational variables let us not only find the optimum operational point regarding energy efficiency but also attain a positive impact on the QoS, which improves the results obtained with current single-variable optimization strategies. The model under consideration includes external noise and does not impose the saturation condition in stations and as such is well suited for real-time industrial applications under noisy channels. Results obtained from simulation confirm the advantages of adjusting simultaneously W and r versus adjusting either one separately, obtaining a slight improvement in energy efficiency and resulting in less loss and delay at the MAC sublayer. Copyright © 2012 John Wiley & Sons, Ltd.