The 802.11 Extensions

The 802.11 Working Group realized that the initial standard that was passed in 1997 would not be sufficient to attract implementers. Therefore, the working group established various task groups with the responsibilities to develop different extensions to the 802.11 standard.

The idea behind having different task groups is to develop standards for different types of usage scenarios that still conform to a basic set of operating rules and are still interoperable to a certain extent.

The most promising standards at this time include 802.11b, 802.11a, 802.11g, and 802.11e. We discuss the extensions in the order of their popularity, development status, and general acceptance.


802.11b is an extension to 802.11 that operates at speeds up to 11 Mbps transmission (with a fallback to 5.5, 2, and 1 Mbps) in the 2.4−GHz band and uses only DSSS. 802.11b is also known as 802.11 high rate or wireless fidelity (Wi−Fi).

Enhancements Offered by 802.11b over 802.11

The 802.11b extension was the product of the 802.11 task group b and was approved in 1999. 802.11b ratifies to the original 802.11 standard, allowing wireless functionality comparable to Ethernet. The 802.11b standard operates up to 11 Mbps, whereas the base 802.11 standard supported speeds of up to 2 Mbps.

  • 802.11b Applications

802.11b is the most widely deployed wireless LAN standard. 802.11b is currently available in the market. Now with operating speeds up to 11 Mbps, it is far more practical to use the wireless LANs than the conventional wired LANs.

It is being used in Small Office Home Office (SoHo) environments, enterprises, and by Wireless Internet Service Providers (WISPs).

  • Small Office Home Office (SoHo)

802.11b is very attractive to home users and to those who operate a small business from home. Users enjoy the instant networking that was very impractical in the recent past.

Now, no cumbersome wiring or understanding of the cable types is needed. Just buy one or more 802.11b−compliant network cards and an AP.

Install according to the manufacturer's instructions and you have a functional computer network. This ease of deployment is making 802.11−based wireless LANs a popular alternative to the wired LANs for SoHo environments.

With 802.11b−compliant APs that come with built−in broadband support, sharing an Internet connection among multiple users is now easier than before. Most APs these days come with DSL or cable modem connectivity that provides the ability to connect a wireless LAN to the Internet.

  • Enterprise

Enterprise users can be more mobile with a wireless LAN that is constructed using 802.11b networking devices. These networks provide scalability and enable users to move about within the organization without worrying about the wiring and other physical constraints.

  • Wireless Internet Service Providers (WISPs) and Community Networks

Internet Service Providers (ISPs) are seeing a great business opportunity in providing wireless Internet access services to mobile users. Today, many Internet cafes, coffee shops, airports, and parks are equipped with 802.11b APs.

These APs are operated by the private WISPs who charge the users for accessing the Internet using their computer. All a user has to bring to such a location is a computing device equipped with an 802.11b network card and a valid credit card to pay for the WISP access fees.

  • 802.11b Limitations

802.11b is haunted by the possibility of interference in the 2.4−GHz frequency band in which it operates. However, the 2.4−GHz frequency is already crowded and will soon be more so.

Microwave ovens operate at 2.4 GHz and can deter the performance of 802.11 wireless networks. Many powerful cordless phones also operate at the 2.4−GHz frequency.

If you use 802.11b networking products, forget about using these phones in the same area. An even greater threat to 802.11b stability is just around the corner.

Blue−tooth, the short−range wireless networking standard, which also operates in the 2.4−GHz range, is slated to coexist with wireless LANs. Bluetooth is not bothered a bit by 802.11b signals, but not vice versa.

Depending on the proximity and number of devices, Bluetooth can have a negative impact on the performance of an 802.11b connection due to electromagnetic interference caused by the Bluetooth devices.

Fortunately, Bluetooth−enabled devices are used for transmission of a small amount of data—for example, synchronization of a phonebook in a cell phone with a desktop computer—over short periods of time and generally do not cause major network problems.

Most interference can be avoided by configuring the 802.11b equipment to choose channels that operate on one end of the spectrum and Bluetooth devices to operate on the other.

That said, however, a visitor equipped with Bluetooth equipment configured to operate in overlapping frequency can still cause limited interference.

  • 802.11b Interoperability and Compatibility with 802.11

802.11b devices are backward compatible with 802.11 implementations, which use the DSSS as their spectrum technology.

Therefore, 802.11b devices operate at lower speeds when they are connected to an 802.11 network. 802.11b devices are not compatible with the HomeRF devices because HomeRF uses the FHSS standard.