VoIP Codec Adaptation Algorithm in Multirate 802.11 WLANs: Distributed vs. Centralized Performance Comparison

摘要

Multirate 802.11 environments are quite problematic for VoIP traffic, with the rate changes of some of the flows affecting the transmission of all others. Building upon our previous results, we propose an algorithm which, based on the combined feedback from Real-Time Control Protocol (RTCP) packets and the MAC layer, can dynamically adapt the codecs of ongoing VoIP calls to adjust them to the multirate scenario. A comparison of both the centralized and distributed versions of the algorithm is provided for a wired-wireless scenario, showing an important capacity and quality increase over the standard case.