Quality assurance of voice over WLANs (VoWLANs) with differentiated services

Abstract

Several technical issues make commercial and large voice over wireless local area network (VoWLAN) services difficult to provide. The most challenging issue when voice over Internet Protocol (VoIP) services are ran over IEEE 802.11-based WLANs is the bandwidth inef f iciency due to the considerable overhead associated with WLAN packet transmission. In this work, we propose a session-based quality-of-service management architecture (SQoSMA) to overcome the low number of VoIP calls in IEEE 802.11 Wireless LANs and the negative effect of new call addition when the WLAN reaches its capacity. The SQoSMA combines data and control planes to detect VoWLAN QoS degradations and performs either an adaptive audio codec switching or a call stopping to fix VoWLAN issues in a differentiated services manner. In addition, our solution deals with user sessions information, by considering user priority (from its agreement) to guarantee a certain level of its multimedia applications. Performance evaluation using a real test-bed shows that call codec change and call stopping techniques can easily assure high-priority calls with acceptable call blocking probability.

Performance Evaluation Voice over WLAN Capacity in Three Standards IEEE 802.11

“…Capacity estimates for both the experimental and simulated network were 15 calls for 64 kb/s CBR VoIP traffic and 38 calls for VBR VoIP traffic with a packetization interval of 20ms and an activity ratio of 0.39 respectively. A quality of service management architecture that is session-based was proposed by Badis Tebbani et al [12] to accommodate for the low capacity of VoIP calls in an IEEE 802.11 wireless local area network as well as resolve the issues that occur when new calls are added to a network that has reached its capacity. Several researchers have studied the throughput and traffic generation parameters of an 802.11 wireless local area network [13] [14].…”

Simulation and Analysis of Quality of Service (QoS) Parameters of Voice over IP (VoIP) Traffic through Heterogeneous Networks

“…To succeed in dealing with the severe problems of VoIP calls over WiFi while approaching the WiFi capacity limit and congestion, a new scheme, the Quality Assurance of Voice over WLANs (SQoSMA) [16] was proposed. SQoSMA took the approach of incorporating the data with the control and planes for detecting and mitigating congestion events.…”

Performance Evaluation of VoIP QoS Parameters Using WiFi-UMTS Networks

“…A study over High Speed Packet Access (HSPA) [15] has shown that not all VoIP implementations are the same as they have differing quality effects on the voice. A strategy used to overcome the quality problems of congestion in WiFi when using VoIP is known as SQoSMA (Session-based Quality-of-Service Management Architecture), Quality Assurance of Voice over WLANs [17]. SQoSMA tries to overcome the bandwidth limitation problems by combining the control and data planes in order to mitigate congestion events by choosing the lowest bitrate adaptive audio codec.…”