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As communications distances grow, it becomes infeasible economically to connect information sources and information users using coaxial cables and fiber optic links. But wireless technology can provide cost-effective access to remote, difficult-to-reach areas.
WiMAX (Worldwide Interoperability for Microwave Access)—or IEE 802.16 or Wireless MAN—provides such broadband wireless access over larger areas than 802.11 (Wireless LAN), and it does so at broadband speeds.
WiMAX highlights
There are four key defining elements that differentiate WiMAX and other wireless technologies.
- WiMAX is a broadband wireless access (BWA) technique, offering fast broadband connections over long distances. It is an IEEE 802.16/ETSI HiperMAN based certificate for equipment fulfilling the interoperability requirements set by the WiMAX Forum (comprising of industry leaders committed to the open interoperability of all products used for broadband wireless access).
- The technology underlying the standard is often referred to as "Wireless MAN wireless local loop" or "WiMAX".
- A key aspect of WiMAX is the interoperability between products from different vendors.
- WiMAX uses different modulation schemes between the consumer and the base station along different distances.
WiMAX architecture
The IEEE Working Group 16 defined two access options for a WiMAX network: fixed (IEEE 802.16TM- 2004) and portable (IEEE 802.16eTM). In the fixed option, access is provided through a fixed antenna as in a satellite television subscriber station. In portable option, the subscriber stations are very similar to IEEE 802.11 Wi-Fi stations.
WiMAX point-to-point backhaul can be used to interconnect Wi-Fi mesh networks through dual mode Wi-Fi and WiMAX cells. It can also be used to offer access to fixed WiMAX point- to-point backhaul, interconnecting Wi-Fi mesh networks through a dual mode Wi-Fi and WiMAX cells.
Furthermore, it can be used to offer access to fixed Subscriber Stations (SS) through a Point to Multi Point (PMP) topology. Mesh topology can be used to reach users, who cannot otherwise be reached without a new Base Station (BS). Portable SS's will be supported in the near future.
The WiMAX architecture depends on: topology and Wi-Fi interconnection. With the emergence of WiMAX in near future, deployments that combine the two technologies can be constructed to take advantage of the strengths of both Wi-Fi and WiMAX. The WiMAX cells will interoperate seamlessly with existing Wi-Fi cells always selecting the best path for delivering maximum user throughput end-to-end.
The scenario will become increasingly complicated with the introduction of five other factors:
- PHY air interface
- Duplexing technique (FDD—Frequency Division Duplexing/TDD—Time Division Duplexing)
- Transmission mode (half-duplex/full-duplex)
- Operation (licensed/unlicensed)
- Adaptive burst profiles
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