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And then there was WiMax

And then there was WiMax

Since the turn of the millennium, wireless networks have proliferated. Wi-Fi, the popular term for the capabilities created by a group of standards from the Institute of Electrical and Electronics Engineers (IEEE), has freed us to move around our offices and many public places with our laptops and handhelds, yet still have instant, unencumbered access to our companies’ intranets and the Internet.

Worldwide Interoperability for Microwave Access (WiMax) is the next step on the road to a wireless world, extending broadband wireless access to new locations and over longer distances, as well as significantly reducing the cost of bringing broadband to new areas.

Among the promises of WiMax is that it could offer the solution to what’s sometimes called the “last-mile” problem, referring to the expense and time needed to connect individual homes and offices to trunk lines for communications.

WiMax promises a wireless access range of up to 50km, compared with Wi-Fi’s 90 metres and Bluetooth’s 9 metres.

802.What? The popularity of wireless networking has grown very quickly because of effective standardisation. Wi-Fi encompasses a family of specifications within the IEEE 802.11 standard. These include 802.11b (the most popular, at 11Mbps, with a typical range of up to 300 feet), 802.11a (54Mbps, but at a shorter range than 802.11b) and 802.11g (combining the speed of a with the range of b).

WiMax is the new shorthand term for IEEE Standard 802.16, also known as Air Interface for Fixed Broadband Wireless Access Systems. It’s been designed from the beginning to be compatible with European standards — something that didn’t happen with 802.11a and delayed its adoption.

The non-profit WiMax Forum was established in 2001 by Nokia, Ensemble Communications and the Orthogonal Frequency Division Multiplexing Forum.

The WiMax Forum aims to support wireless metropolitan-area networking products based on 802.16, much as the Wi-Fi Alliance has done for wireless LANs and 802.11.

The organisation has most recently been working on standards certification and interoperability testing. In 2003, Intel became a major supporter of the WiMax Forum.

The initial version of the 802.16 standard, approved by the New York-based IEEE in 2002, operates in the 10 to 66GHz frequency band and requires line-of-sight towers.

The 802.16a extension, ratified in March 2003, doesn’t require line-of-sight transmission and allows use of lower frequencies (2 to 11GHz), many of which are unregulated. It boasts a 31-mile range and 70Mbps. data transfer rates that can support thousands of users.

Vendors have held interoperability forums, and the first commercial products are expected to appear on the market next year.

Additional 802.16 standards are in the works; here’s what they’ll cover:

• 802.16b — Quality of service.

• 802.16c — Interoperability, with protocols and test-suite structures.

• 802.16d — Fixing things not covered by 802.11c, which is the standard for developing access points.

• 802.16e — Support for mobile as well as fixed broadband.

Technology considerations

The overall concept of metropolitan-area wireless networking, as envisioned with 802.16, begins with what’s called fixed wireless. Here, a backbone of base stations is connected to a public network, and each base station supports hundreds of fixed subscriber stations, which can be both public Wi-Fi hotspots and firewalled enterprise networks. The base stations would use the Media Access Control layer defined in the standard — a common interface that makes the networks interoperable — and would allocate uplink and downlink bandwidth to subscribers according to their needs, on an essentially real-time basis.

Later in the development cycle, with 802.16e, WiMax is expected to support mobile wireless technology — that is, wireless transmissions directly to mobile end users. This will be similar in function to the General Packet Radio Service and the “one times” radio transmission technology (1xRTT) offered by phone companies.

Intel has now promised WiMax versions of its Centrino chip set for 2004. Nokia said it would have battery and other technical issues solved in time to launch a WiMax mobile phone in 2005.

Following on the heels of WiMax is another standard, IEEE 802.20, which addresses wide-area wireless networks and is currently under development; no products supporting 802.20 are expected before 2006.

The promise

The Washington-based Cellular Telecommunications & Internet Association reports that in 2000 there were more than 109 million mobile subscribers — compared with 58 million residential wired telephone lines (according to US government data). If we consider that part of the telecommunications industry to be an indicator of what is to come in data networking, it’s likely that in a few years, much of the Internet’s traffic will be carried over the air via WiMax and its descendants, not over copper wires or optical fibre.

Market research firm, Visant Strategies, predicted that WiMax product sales would reach $US1 billion by 2008.

ABI Research said the market for long-range wireless products based on 802.16 and the forthcoming 802.20 standard would reach $US1.5 billion by 2008.


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