A wireless traffic probe for radio resource management and QoS provisioning in IEEE 802.11 WLANs
MSWiM '04 Proceedings of the 7th ACM international symposium on Modeling, analysis and simulation of wireless and mobile systems
A Novel Framework for Radio Resource Management in IEEE 802.11 Wireless LANs
WIOPT '05 Proceedings of the Third International Symposium on Modeling and Optimization in Mobile, Ad Hoc, and Wireless Networks
Adaptive VoIP Playout Scheduling: Assessing User Satisfaction
IEEE Internet Computing
An Assessment of the Audio Codec Performance in Voice over WLAN (VoWLAN) Systems
MOBIQUITOUS '05 Proceedings of the The Second Annual International Conference on Mobile and Ubiquitous Systems: Networking and Services
The ETSI computation model: a tool for transmission planning of telephone networks
IEEE Communications Magazine
IWCMC '07 Proceedings of the 2007 international conference on Wireless communications and mobile computing
Proceedings of the 11th communications and networking simulation symposium
Best Approach for Video Codec Selection Over VoIP Conversation Using Wireless Local Area Network
International Journal of Interdisciplinary Telecommunications and Networking
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In this paper we experimentally study the relationship between resource utilization in the wireless LAN and the quality of VoIP calls transmitted over the wireless medium. Specifically we evaluate how its overall capacity is shared between three basic MAC bandwidth components (load, access, and free) as the number of VoIP calls increases and how it influences transmission impairments (delay, loss, and jitter) and thus call quality. Resource utilization (under the MAC bandwidth components framework) is calculated by a WLAN probe application that passively "sniffs" packets at the L2/MAC layer of the wireless medium and analyses their headers and temporal characteristics. The quality of VoIP calls is predicted using an extended version of the ITU-T E-model, which estimates user satisfaction from time varying transmission impairments. Through experimentation with various codecs and packetization schemes we found that as the load (number of calls) reaches the available capacity level, packet delays and jitter increase dramatically resulting in the call quality becoming degraded. We show how these MAC bandwidth components maybe used to assess the VoIP call quality on 802.11 WLANs.