VoIP Quality Enhancement with Wideband Extension Method in Broadband Networks

Voice over Internet Protocol (VoIP) is one of the most important technologies in the world of communication. In this work, end-users connect via ADSL modem to broadband IP network and a variety of multimedia services utilized in this network. VoIP is the most important services in the broadband network and attempts focused on improving quality of voice in VoIP toward the quality of voice in PSTN. Perceived voice quality is an important function in VoIP applications. The main aim is to find an efficient speech enhancement method for perceptual optimization of voice quality. In this work, use band-width extension (BWE) method to estimate wideband envelope and improve quality and intelligibility. This method applies to some common codecs (e.g. G.711/ G.726/ G.729/ iLBC, speex) and then evaluates quality with ITU P.862.2 (wideband PESQ). Simulation takes under both low packet loss conditions and non packet loss conditions. The results illustrate that the BWE algorithm can achieve reliable perceived voice quality in comparison with the previous condition.