VoIP Quality Evaluation in Mobile Wireless Networks

Managing voice service quality over both IP-based wired and wireless networks has become a challenge, especially in a heterogeneous network environment. This paper discusses the issues that affect voice quality in a mobile wireless network. We compare the wireless Voice over IP (VoIP) quality performance using a combination of voice codecs and three mobility management protocols (MMP), which are Mobile IPv6 (MIP), Hierarchical Mobile IPv6 (HMIP) and the proposed Hierarchical Mobile IPv6 with Buffering Extension. The evaluation is based on ITU-T recommended MOS (Mean Opinion Score) and E-Model factors. Time varying impairments are also considered. Our evaluation shows that the proposed MMP provides a higher voice quality performance especially for low bit rate voice codecs.