Voice and Video Capacity of a Secure IEEE 802.11g Wireless Network

摘要

This paper describes an empirical evaluation of the ability of an IEEE 802.11g network to transport audio and video as well as compare audio quality in the presence and absence of an access point within an office environment using standard off-the-shelf hardware and default device configurations. The impact of securing the audio stream with WPA (WiFi Protected Access) on the perceived quality is also examined. Following the ITU-T P.800 recommendation, thirty-six human subjects assess audio and video quality using a Mean Opinion Score (MOS) on a wireless multimedia system. Experimental data suggest that securing the voice traffic has no significant effect on the quality of the audio signal received. Furthermore, an 18.4% improvement in the perceived quality of the audio signal can be achieved by routing the audio and video traffic through an access point instead of allowing the audio and video traffic to flow directly between two arbitrary nodes within a wireless local area network. Furthermore, increasing the number of conversations reduces the perceived quality of the audio signal by 23.5% and the video signal by 16.8%. Disabling video increases the perceived audio quality by 38.9%. This paper shows that the usable capacity, based on signal quality, of a standard IEEE 802.11g wireless multimedia system deployed in an office environment is two audio-only conversations or one audio/one video connection on the wireless network.