IEEE 802.11 Protocol- Quality of service

The success of IEEE 802.11 technology (Wi-Fi for Wireless Fidelity) in the field of wireless LANs is undeniable. Although the first version of this standard was published in 1997, and quickly equipped most laptops and mobile terminals, its deployment as a network access technology only really took off when a large proportion of users had a mobile terminal. The advent of smartphones, followed by ultra-portable computers and touch-screen tablets, has accentuated this phenomenon. Wi-Fi network coverage is now such that this technology, which transposes Ethernet to a radio-frequency medium, offers a viable alternative to cellular data networks (UMTS) in urban environments. IEEE 802.11 technology is, however, suffering from its own success. The most widely used frequency band, 2.4 GHz, is saturated, and it is difficult for individual users to achieve the throughput promised by the standard in an urban environment.

At the same time, the range of multimedia services available over the Internet has grown enormously, and the network now carries both streaming audio and video content, as well as raw data. A significant proportion of audio and video conversations are also carried over the Internet, often ending up on a wireless link. The quality of today's multimedia content is such that several triple-play service providers are now recommending the use of powerline carriers, in the absence of an Ethernet connection, to connect the set-top box to the access equipment.

Since its latest revision in 2007, the IEEE 802.11 standard has included an extension for quality of service. This extension, initially published under the reference IEEE 802.11e, designates several mechanisms for defining and implementing access priorities to the wireless medium. A specific certification, called WMM (Wireless MultiMedia), is granted by the Wi-Fi Alliance to attest to the compatibility of interface cards with the core of this extension. While this extension does not solve the problems of radio spectrum saturation and interference between nearby networks, it does facilitate the use of applications requiring guaranteed delay or bandwidth on wireless links.