Impact of fragmentation threshold tuning on performance of voice service and background traffic in IEEE 802.11b WLANs

This paper deals with measurements of the impact of fragmentation threshold tuning on speech quality and background traffic throughput in mixed voice/data transmission in an environment of WLANs (IEEE 802.11b). The ITU-T G.729AB encoding scheme is deployed in this study and the Distributed Internet Traffic Generator (D-ITG) is used for the purpose of the background traffic generation. The primary goal of generated background traffic is to affect the speech transmission by changing of VoIP connection network performance parameters such as jitter (delay variation), and packet loss. In general, those parameters have a significant impact on overall speech quality perceived by user. The speech quality and performance of background traffic are assessed by means of the accomplished PESQ algorithm and Wireshark network analyzer, respectively. This experiment shows that fragmentation threshold tuning can significantly decline speech quality and performance of background traffic.