A Novel Mobility-Aware Playout Algorithm for VoIP Services

The latest explosive growth in mobile networks has resulted in an increasing interest in optimisation techniques for mobile services. Resent advances in mobile wireless networks incorporate link-layer intelligence in order to enhance the performance of network and application layers. The Media Independent Handover (MIH) standard provides a framework that can make such link-layer intelligence available to upper layers. In this paper, a novel MIH-enabled playout algorithm for Voice over Internet Protocol applications is presented that aims to compensate for the degradation of voice quality caused by handovers. To that end, link-layer triggers in conjunction with speech time-scale modification techniques are exploited to mitigate the increase in delay and jitter induced by the handover process. Results of subjective listening tests show typical gains of 0.3 on a 5-point scale of the Mean Opinion Score with respect to existing playout scheduling schemes.