Mobility impact of VoIP quality over radio access network

Voice over IP (VoIP) has been deployed over the wireline networks for the last decade. It achieved remarkable success of the adaptation as the replacement of circuit switched legacy voice service. It also enabled the service providers to converge data and voice services over a single broadband network. This evolutionary activity has been also initiated in the wireless network as the emergence of broadband wireless network. VoIP has been initially applied to the Wireless Local Area Network (WLAN) over 802.11a/b/g interface. It also has been applied to the Wireless Wide Area Network (WWAN) since 3G networks were deployed. In addition, convergence of wireline and wireless network would accelerate the adoption of VoIP application over the wireless network.;Within several key technical challenges such as transport efficiency and QoS, we selected Voice quality assurance as the dissertation topic since it becomes more critical issue on the mobility network, especially over the handoff period where the additional packet transmission delay, jitter and loss occurs. We presents the enhanced packet based VoIP quality monitoring and measurement method as well as a validation method on a cross-check with the speech quality measurement.;We also present an enhanced method for the VoIP quality measurement from the existing E-model, and applied the method to the EVDO Radio Access Network (RAN) as an experiment. The EVDO RAN has been deployed as 3G network in US while it typically supports up to approx. 2Mpbs forward link and up to 153 kbps over reverse link to offer data service an the evolution of CDMA2000.;However, EVDO also offers the technical challenge to overcome the performance fluctuation upon the mobility. We address the technical issues on the existing E-model when it is applied to the EVDO, and propose an enhanced method expanding the existing E-model well suited to the VoIP over the EVDO. We also use the Anique+ for the reference to verify that the proposed solution produces the superior accuracy to the existing E-model based measurement.;Once we analyzed the correlations between E-model and Anique+ as a reference, we applied to the mobility impact on EVDO network by measuring the packet loss, jitter and data throughput impact by the EVDO forward link handoff. We also investigate the unvoiced frame effect on the packet loss by detecting the VoIP packet type. Unvoiced frame type is useful to compromise VoIP quality impact by the burst packet loss during the handoff since it takes more than 50% of the VoIP frames.;We investigated the mobility impact on the VoIP service caused by the handoff, and define a validation model with leverage of both E-Model and Anique+. Our experimental analysis over the EVDO network proved the mobility impact on the VoIP quality due to handoff. We achieved the optimal size of receiver buffer and data throughput that are recommended for VoIP application configuration to minimize the mobility impact.