Currently the Internet provides users with access to information across the world using IP technology. Until now most access points to the Internet have been fixed stations at given locations, but with increasing sales of mobile devices, mobility has become a major trend. Therefore, the Internet is becoming more and more heterogeneous due to the recent explosion of wireless networks. The IEEE 802.11 wireless LAN (WLAN) is the most widely used WLAN standard nowadays. Currently the IEEE 802.11 standard specifies an over-the-air interface between wireless devices. However, QoS services over this technology are still being defined aiming to provide support to multiple applications. Thus, a large number of 802.11 QoS enhancement schemes are being considered and proposed by the research community and standard bodies. This paper presents a survey of current research activities. We also overview the upcoming IEEE 802.11e standard, a proposal defining the mechanisms for wireless LANs aiming to provide QoS support to QoS-sensitive applications. © Springer-Verlag Berlin Heidelberg 2004.