Analysis of Cross-Layer Interactions for VoIP Services over Ad-Hoc Networks

This paper examines the cross-layer interactions of different protocols, for wireless ad-hoc networks in the presence of VoIP traffic. VoIP traffic in mobile wireless Ad-Hoc networks is severely affected by interactions between different layers. The reliability and the strict congestion control offered by TCP is often times unnecessary. At the same time the prioritization scheme of 802.11e favours delay-sensitive traffic, hence it enhances the VoIP performance. We concentrate our work in the Transport and the Routing layer, where different protocols have different impact on the way the VoIP traffic performs. Using a simulation environment, these interactions have been studied among the following protocols on the transport layer (i.e. TCP, DCCP, SCTP), the routing layer (i.e DSDV, AODV, DSR) and the MAC layer where the 802.11e is utilized. The impact of these parameters on voice quality in terms of throughput, packet loss, delay and jitter are evaluated.