Wimax

Uses

The bandwidth and range of WiMAX make it suitable for the following potential applications:

• Connecting Wi-Fi hotspots to the Internet.
• Providing a wireless alternative to cable and DSL for "last mile" broadband access.
• Providing data and telecommunications services.
• Providing a source of Internet connectivity as part of a business continuity plan. That is, if a business has a fixed and a wireless Internet connection, especially from unrelated providers, they are unlikely to be affected by the same service outage.
• Providing portable connectivity.

rchitecture

The WiMAX Forum has defined an architecture that defines how a WiMAX network connects with other networks, and a variety of other aspects of operating such a network, including address allocation, authentication, etc. An overview of the architecture is given in the illustration.

This defines the following components, plus a number of interconnections (or reference points) between these, labeled R1 to R5 and R8:

• SS/MS: the Subscriber Station/Mobile Station
• ASN: the Access Service Network^[8]
• BS: Base station, part of the ASN
• ASN-GW: the ASN Gateway, part of the ASN
• CSN: the Connectivity Service Network
• HA: Home Agent, part of the CSN
• AAA: AAA Server, part of the CSN
• NAP: a Network Access Provider
• NSP: a Network Service Provider

It is important to note that the functional architecture can be designed into various hardware configurations rather than fixed configurations. For example, the architecture is flexible enough to allow remote/mobile stations of varying scale and functionality and Base Stations of varying size - e.g. femto, pico, and mini BS as well as macros.

[edit]Comparison with Wi-Fi

Comparisons and confusion between WiMAX and Wi-Fi are frequent, possibly because both begin with the same two letters, are based upon IEEE standards beginning with "802.", and are related to wireless connectivity and Internet access. However, the two standards are aimed at different applications.

• WiMAX uses licensed spectrum to deliver a point-to-point connection to the Internet from an ISP to an end user. Different 802.16 standards provide different types of access, from portable (similar to a cordless phone) to fixed (an alternative to wired access, where the end user's wireless termination point is fixed in location.)
• Wi-Fi uses unlicensed spectrum to provide access to a network.
• WiMAX and Wi-Fi have quite different Quality of Service (QoS) mechanisms. WiMAX uses a mechanism based on connections between the Base Station and the user device. Each connection is based on specific scheduling algorithms. Wi-Fi has introduced a QoS mechanism similar to fixed Ethernet, where packets can receive different priorities based on their tags. For example VoIP traffic may be given priority over web browsing.