Session-Based QoS Management Architecture for Wireless Local Area Networks

Abstract

International audienceGrowing demands for the public wireless broadband services will require more capacity than the one provided by IP-based service providers (ISPs). The increasing popularity of WLANs due to the use of license-free radio spectrum with low-cost, easily deployable, high-data-rate wireless services, has encouraged service providers to consider their deployment in high density usage areas such us public hotspots to provide complementary broadband access to their networks and services. In order to provide consistent QoS control for multimedia applications (VoIP, VoD,...) over hotspots, a Session Initiation Protocol (SIP) based QoS management architecture is proposed in this article. Performance evaluations are discussed to illustrate the feasibility of the proposed architecture

Codec-based adaptive QoS control for VoWLAN with differentiated services

“…If the problem continues after the audio codec changes (because bad channel conditions for example), the algorithm stops a VoIP session with the lowest priority in order to relax the network [1].…”

“…Once our architecture features [1] and test results are used (inter-controller communications and threshold values) to regulate our proposed session-based QoS management algorithm SQoSMA. Every Interval Monitoring Time (set to 2 seconds in our implementation), each controller i tests all its VoIP sessions by checking at each time all communications between ends within its cell and ends within the corresponding cells (controlled by another controller j ).…”

“…The one-way end-to-end VoIP delay is made up of three delays, in a worst-case scenario both ends are on wireless access networks connected by a wired IP-based backbone. So, the three delays are: As regards to Backbone delay we have chosen the Ipanema measurement tool [9] to regularly measure delays between each controller and all other controllers [1]. However, because regular measure in a wireless network generates unacceptable overhead and requires hard synchronization, we have investigated a way to determine up and down delay according to the number of active VoIP sessions within one wireless cell.…”

“…In this paper, we propose an extension of our previously proposed session-based QoS management architecture [1] that integrates a service access control and a service provisioning. In this work we have focused on the guarantee features of network QoS that differentiates it from the Best-Effort network services.…”

“…Thus, in order to guarantee the quality of high priority sessions, we propose to downgrade the quality (low but acceptable MOS) of user sessions with low priority by changing their used codecs (e.g., ITU G729 instead of ITU G711). This technique and all related monitoring functions are defined into the proposed session-based QoS management architecture [1]. In order to validate our approach a complete test-bed is made up by which we have performed some feasibility and gain tests.…”