Abstract—IEEE802.16 technology due to its outstanding larger coverage area, high data rates, inexpensive equipments, ease of deployment and guaranteed QoS make it a suitable candidate for future broadband wireless access networks. The Mobile WiMAX has been designed to provide Broadband Internet service to mobile users. The VoIP is flexible and provides low cost telephony to customers over the existing IP infrastructure. However, there are still many challenges that need to be addressed to provide a steady and good quality voice connection over the best-effort Internet. In this paper we evaluate the performance of different VoIP codecs over the best effort WiMAX network. The network performance metrics such as jitter, one way delay, and packet loss and user perception metric that is Mean Opinion Score have been used to evaluate the performance of VoIP codecs. The simulation is performed in QualNet simulator with varying values of Packet size, number of calls and jitter buffer sizes. Our results indicate that varying the jitter buffer size and packetization time affects the quality of voice over the best effort network.

Index Terms—WiMAX, VoIP, BE, MOS, QoS, RTP, QualNet.

M. Imran Tariq and Yoichi Shinoda are with Japan Advanced Institute of Science and Technology, (JAIST) 1-1 Asahidai, Nomi, Ishikawa, 923-1292 Japan (e-mail: imran@jaist.ac.jp).
M. Ajmal Azad is with INESCPORTO, Faculty of Engineering, University of Porto, Portugal (e-mail: mazad@inescporto.pt).
Razvan Beuran is a researcher with National Institute of Information and Communication Technology (NICT), Ishikawa Japan.