Limitations and capabilities of QoS support in IEEE 802.11 WLANs

The IEEE 802.11 wireless LAN (WLAN) is the most widely used standard nowadays for wireless LAN technology. However, the current standard does not provide QoS support required by the wide range of end applications (e.g., multimedia communications). In this work we first analyze the QoS limitations of legacy DCF and PCF IEEE 802.11 wireless MAC. Then, we also present the upcoming IEEE 802.11e standard being introduced. The IEEE 802.11e standard is a proposal defining the mechanisms for wireless LANs aiming to provide QoS support to time-sensitive applications, such as, voice and video communications. Finally, we carry out a comparative study of legacy DCF and the IEEE 802.11e (EDCA) upcoming standard, when supporting different services, such as voice, video, best-effort and background traffic.