Voip over wifi - degradation analysis with flat fading emulator

VoIP over WiFi - degradation analysis with flat fading emulator
Omar Carvalho Branquinho(*)
Pontificia Universidade Catolica de Campinas (*)Voluntary Researcher-Computation Institute-UNICAMP P.O. Box 317 13086-900 Campinas - SP - Brazil [e-mail]

Pedro Henrique Gomes
University of Campinas - UNICAMP Avenida Albert Einstein, 1251 13084-971 Campinas - SP - Brazil [e-mail]

Rafael Seraphin Seste
University of Campinas - UNICAMP Avenida Albert Einstein, 1251 13084-971 Campinas - SP - Brazil [e-mail]

Tatiane Silvia Leite
University of Campinas - UNICAMP Avenida Albert Einstein, 1251 13084-971 Campinas - SP - Brazil [e-mail]

Abstract— It is well known that the quality of real-time applications, like VoIP, in wireless networks suffers great degradation due to the signal instability in mobile environments. In this paper the quality of VoIP applications on WiFi networks is evaluated using an emulation system with variation of the test environment following the Rayleigh distribution. With this system it is possible to maintain control of the environment and modify it, emulating real situations of WiFi networks in obstructed places. Index Terms— Flat Fading, QoS, Rayleigh, VoIP, Weibull, WiFi.

To test the quality of VoIP applications on 802.11b networks a wireless network emulation system was built in the Wireless Communication Laboratory at PUC-Campinas, in partnership with WCN-Intel Laboratory at UNICAMP. This project included the development of customized software that controls the emulation of flat fading channel with Rayleigh distribution. II. W I F I A. 802.11 standard

I. I NTRODUCTION Currently Voice over Internet Protocol (VoIP) and Wireless Local Area Networks (WLANs) are two technologies of great prominence in the market and in scientific research. The current status indicates that the convergence of these two technologies will create a new