Approaches for improving VoIP QoS in WMNs

This paper focuses on proposing approaches for the improvement of Voice over Internet Protocol (VoIP) service quality in Wireless Mesh Network (WMN). While WMNs have self-healing, self-forming and dynamic topology features, they still pose challenges for the implementation of multimedia applications, such as voice, in various scenarios. The research has been conducted using a network simulator and experiments conducted on three main scenarios with mesh nodes in no-mobility, partial mobility and full mobility deployments. The experiments consider the IEEE 802.11n/g/e/s standards; G.711, G.726 and G.729 voice codecs; and AODV-reactive, OLSR-proactive and HWMP hybrid routing protocols. The measurement and evaluation is based on the Mean Opinion Score (MOS) rating-scale defined by ITU-T standard and supported by the delay, jitter and packet loss metrics. The proposed approaches identify the integration choices and inclusion of supportive mesh nodes in order to improve VoIP quality. The analysis of the results show that our proposed approaches improve the VoIP quality in terms of 5 point MOS rating-scale by 0.2 in no mobility, 2.2 in partial mobility and 0.9 in full mobility scenarios. The results show that whereas minor gains are achieved in the no-mobility scenarios, significant and considerable gains are achieved for the full mobility and partial mobility scenarios, respectively. The results for the two latter cases thus illustrate the merit of the proposed approach.