Investigating the Effects of Encoder Schemes, WFQ & SAD on VoIP QoS

Voice Encoder Schemes, Weighted Fair Queuing (WFQ) and Speech Activity Detection (SAD) techniques affect the overall Quality of Service (QoS) of Voice over Internet Protocol (VoIP) services. VoIP is one of the most discussed and rapidly emerging technologies in telecommunication. We are slowly witnessing a change in telephony from Public Switched Telephone Network (PSTN) to IP based VoIP Network. Despite the benefits being enormous, the switch to VoIP hasn’ t been swift, primarily due to various performance (delay, jitter, packet loss, echo etc.) and security issues plaguing the VoIP telephony network. To achieve minimal QoS for telephony, the voice (packets) must be delivered within 150 ms to 200 ms. This paper presents a performance model to quantifying the influence of VoIP which gives an in-depth understanding of how Voice Encoder Schemes, WFQ and SAD influence VoIP QoS from a theoretical and implementation point of views.