AP selection algorithm for VoIP services in mixed traffic WLAN environment

Recent rapid developments of high-speed wireless access technologies enable us to use real-time multimedia services as well as legacy non-real-time services via wireless access systems. These multimedia services require QoS (Quality of Service), such as low PLR (Packet Loss Rate) and short delay time. To provide QoS guarantee in wireless LAN (Local Area Network) environment, this paper proposes a new AP (Access Point) selection algorithm, RPFA (Real-time Prioritized Fairness Association), for large-scale wireless LAN system, which is based on capacity utilization of an AP and the number of associated stations to an AP. This algorithm is effective when real-time UDP (User datagram Protocol) traffic and non-real-time TCP (Transmission Control Protocol) traffic coexist. Simulation results show improvements of VoIP (Voice over Internet Protocol) PLR, delay time and R-values for real-time VoIP application and throughput fairness for non-real time FTP application, and also show expansion of a VoIP capacity of wireless LAN system compared to legacy algorithms.