Adaptive approach for QoS support in IEEE 802.11e WLAN Joe Naoum-Sawaya, Bissan Ghaddar, Sami Khawam, Haidar Safa, Hassan Artail, and Zaher Dawy Wireless and Mobile Computing, Networking and Communications (WiMob) 2005 2018-11-30

Problem Parameters are depending on traffic category, not network state or network contention level EDCA technique resets the CW of each station after each successful transmission to CWmin 2018-11-30

Propose A new adaptive EDCA technique that adapts CW to channel conditions and adjusts it depending on the network utilization and performance They estimate channel congestion level start from the fact that CW value ranges in the interval [CWmin, CWmax] 2018-11-30

Propose To optimize further ratio, they use a weight that reflects the certainty of the channel estimation The weight is decreased as time elapses between consecutive transmissions They fixed weight to 0.9 because video streaming is characterized by transmission occurring at very small time intervals 2018-11-30

Performance evaluation Their simulations were implemented using ns-2 They compare three parameters: bit rate, end-to-end packet delay, and packet drop rate In simulation, 4 source-destination pair with 4 different priorities. Each source is a CBR over UDP The levels of priority in EDCA are called access categories (ACs). 2018-11-30

Performance evaluation The levels of priority in EDCA are called access categories (ACs). 2018-11-30

Performance evaluation The levels of priority in EDCA are called access categories (ACs). 2018-11-30

Performance evaluation The levels of priority in EDCA are called access categories (ACs). 2018-11-30

Design of medical-grade wireless LAN Sunghwa Son ssh@dgist.ac.kr Adviser: Prof. Kyung-Joon Park 2018-11-30

Absolute priority Absolute priority mechanism It can assure the absolute priority of each category with respect to lower-priority ones AC Length of AIFS 802.11e Absolute priority AC0 5.00E-05 5.00E-05(AIFS0) AC1 0.00019(AIFS0+CW0) AC2 7.00E-05 0.00049(AIFS1+CW1) AC3 1.50E-04 0.00111(AIFS2+CW2) 2018-11-30

My proposal Absolute priority is so strict that lower priority traffic may not have enough change for channel access Low priority traffic should wait for a large AIFS, even there is no high priority traffic >> waste of the time and resource My proposal adaptively changes AIFS with respect to network condition 2018-11-30

Performance evaluation Simulate with ns-2 3 alarm nodes and 20 TCP connections The levels of priority in EDCA are called access categories (ACs). 2018-11-30

Compare with my simulation Adaptively change CW vs. AIFS After successful transmission, does not resets the CW to CWmin vs. reset to CWmin Sources with only UDP vs. UDP and TCP 4 priorities with video streaming vs. alarm, streaming, and data transmission 2018-11-30