New Telecoms Technology: WiMAX

Daniel Moore from http://iq.insight.com has kindly contributed the following blog post:


WiMAX?
Sounds like a cross between games console and a discount clothes store… Actually it’s no such thing. WiMAX is a new telecoms technology designed to provide wireless data over long distances in a variety of ways – from point-to-point links to full mobile cellular access.

In other words, it enables the delivery of last-mile wireless broadband access as an alternative to cable and DSL.

Why WiMAX?
Simple really. Short for Worldwide Interoperability for Microwave Access, WiMAX is actually a term coined to describe standard, interoperable implementations of IEEE 802.16 wireless networks; similar to the way the term Wi-Fi is used for interoperable implementations of the IEEE 802.11 Wireless LAN standard. However, WiMAX is very different from Wi-Fi in the way it works.

So what is different?
The biggest difference between WiMAX and its aging cousin Wi-Fi isn’t speed, but distance. WiMAX outdistances Wi-Fi by, literally, miles. Where Wi-Fi’s range is measured in metres (usually about 30); WiMAX can blanket a radius of 50 kilometres with wireless access. The increase in range is due to the frequencies used and the power of the transmitter. Of course, at such distances, factors like terrain, weather, and large buildings will act to reduce the maximum range in some circumstances, but the potential is there to cover huge tracts of land. WiMAX is also highly scalable from small remote stations to multi-sector ‘maxi’ scale bases that handle complex tasks.

But WiMAX and Wi-Fi sound so similar…
Thanks largely to the fact that they begin with the same two letters, that they are both based upon IEEE standards beginning with “802”, and that both have a connection to wireless connectivity and the Internet, comparisons and confusion between WiMAX and Wi-Fi are frequent. But the two standards are actually aimed at completely different applications. WiMAX is a long-range system 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 mobile devices such as laptops, PDAs, and mobile phones, to fixed points – as an alternative to wired access, where the end user’s wireless termination point is fixed in location.

WiMAX and Wi-Fi also have quite different Quality of Service (QoS) mechanisms, with WiMAX using a mechanism based on setting up connections between the Base Station and the user device. Each connection is based on specific scheduling algorithms, which means that QoS parameters can be guaranteed for each flow.
How does it work?

WiMAX systems generally consist of two parts:
• A WiMAX tower – similar in concept to a mobile phone mast, a single WiMAX tower can provide coverage up to 8,000 square kilometres.
A WiMAX receiver – where the receiver and antenna could be

• a small box or PCMCIA card, or could be built into a laptop the way Wi-Fi access is today.

A WiMAX tower station can connect directly to the Internet using a high-bandwidth, wired connection. It can also connect to another WiMAX tower using what’s called a line-of-sight, microwave link. This connection to a second tower (sometimes referred to as a backhaul), along with the ability of a single tower to cover up to 8,000 square kilometres, is what allows WiMAX to provide coverage to remote rural areas.

There are two types of WiMAX service…
• The non-line-of-sight, Wi-Fi type service, where a small antenna on the computer connects to the tower. In this mode, WiMAX uses a lower frequency range of 2GHz to 11GHz which is similar to Wi-Fi. Lower-wavelength transmissions are not as easily disrupted by physical obstructions and they are better able to bend around obstacles.

•The line-of-sight service, where a fixed dish antenna points straight at the WiMAX tower from a rooftop or pole. The line-of-sight connection is stronger and more stable, so it’s able to send a lot of data with fewer errors. Line-of-sight transmissions use higher frequencies, with ranges reaching a possible 66GHz. At higher frequencies, there is less interference and lots more bandwidth.

Why do we need it?
In practical terms, WiMAX operates in a similar way to Wi-Fi but at higher speeds, over greater distances and for a greater number of users. As such it could potentially erase remaining suburban and rural blackout areas. The bandwidth and reach of WiMAX also make it suitable for connecting Wi-Fi hotspots and other points, and as an alternative source of connectivity from a business continuity point of view. i.e Separate fixed and wireless Internet connections, especially from unrelated providers, are unlikely to be affected by the same user vice outage.

Why else is it important?
The benefits largely speak for themselves from a commercial perspective, but WiMAX will also be useful in providing robust communications in emergency or terrorist situations, where it could be used as a back-up (or even primary) communications system, as it would be difficult to destroy with a single, pinpoint attack.

Here, a cluster of WiMAX transmitters is set up in range of a key command centre, but as far from one another as possible; each positioned in a bunker, or similar, hardened against bombs and / or other forms of attack. In this way, no single attack could destroy all the transmitters, so the command centre remains in communication at all times.

When are we getting it?
Intel is already WiMAX enabling its Centrino laptop processor range, which should go a long way toward making WiMAX a success.

Indeed, it is predicted that all new laptops will incorporate WiMAX by end of this year, which should see demand ramp further as the risk of deployment disappears and more and more companies therefore roll-out WiMAX-based connectivity across their organisations.


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Stemming off from its quarterly magazine, iQ, it is dedicated to providing you with independent, educational and motivational content, enabling you to make informed IT decisions.

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