Modifications to IEEE 802.11e EDCA to solve starvation using QualNet

Abstract

Wireless LANs are one of the fastest-growing wireless technologies. IEEE 802.11 is a standard for wireless LANs. This doesn't provide Quality of Service (QoS) for multimedia applications. IEEE 802.11e enhances the QoS in wireless LANs. It introduces the Access Categories (AC) by using Enhanced Distributed Channel Access (EDCA). It is a MAC protocol supporting service differentiation through different ACs. EDCA offers different priorities for different types of traffic. Every station contains four transmission queues, one for each AC. Every Access Category (AC) has its own channel access parameters, including Arbitration Inter-Frame Space (AIFS), minimum and maximum Contention Window (CWmin and CWmax), and Transmission Opportunity (TXOP). The high-priority AC will have shorter AIFS and CW than the low-priority AC and high TXOP. Due to this, low-priority traffic is starved by high-priority traffic. This paper proposes modifications to IEEE 802.11e to achieve better performance and prevent starvation of low-priority traffic. By modifying the channel access parameters such as AIFS period and CW size, the TXOP starvation problem is solved. In this work QualNet 7.3 is used.