VoIP over WiMAX: Quality of experience evaluation

VoIP applications are being widely used in today´s networks challenging their capabilities to provide a good quality of experience level to the users. In particular, new wireless broadband technologies, such as WiMAX, are being deployed and need to be evaluated to check the performance levels of VoIP services. The work presented in this paper is a unique contribution assessing the VoIP sessions quality on a real WiMAX test-bed, using UDP/RTP and DCCP transport protocols. VoIP quality is measured according the quality perceived by the end users as well as through conventional network parameters, such as one-way delay and packet loss. The results put in evidence a good quality for VoIP services with 60 simultaneous users in a WiMAX link with resources pre-provisioned. Moreover, in the scenarios tested, DCCP has not shown enhanced performance when compared with UDP/RTP, despite the congestion control mechanisms natively supported.