Voice over WiFi

Abstract

The increases of using mobile computers and communication devices by people have caused the increase in demand of wideband wireless connection services. Therefore, VoIP over WLAN has also become an important and fast growing Internet application. The objective of this project is to investigate the performance of VoIP over WLAN. In this project, the WiFi module (WLAN) in OPNET has been used in order to develop voice services simulations for different QoS requirements. Firstly, by using a simple voice traffic model, a simple point-to-point connection between 2 terminals is developed using OPNET; in addition, the maximum number of simultaneous number of conversations supported by WiFi using different voice codec schemes are obtained. Further investigation is undertaken in relation to how the performance of voice traffic is influenced by the presence of coexisting traffic from other application such as ftp, web browsing, e-mail, etc. After investigation in different scenarios, it has been found that there are two major technical problems are standing in the way. The first one is that the system efficiency for voice traffic could be quite low in WLAN. The second one is that VoIP traffic performance would be degraded in the presence of coexisting traffic from other applications. Finally, a proposed scheme has been implemented to improve the performance and weaken the problems.