WiMax Info

Everything you always wanted to know about WiMax

Well, some of the stuff anyway..


, or Worldwide Interoperabilty for Microwave Access, is a wireless Internet Access system. You can either buy a little PCMCIA card that you plug into your laptop, if you are within 6km of a WiMax tower, or you can get another card for your PC which uses an outside aerial if you are within 30km of a WiMax tower.

WiMax can also handle VoIP (Voice calls), Video conferencing and multimedia.

WiMax has a data carrying rate of 70 Mbps per channel, so if you are sharing this channel with 70 other users, you will still get 1Mbps connection speed, and the WiMax Forum speaks about up to 5Mbps to end users, which is pretty good. Apparently, once the system is up and running and has gained some popularity, the costs will be a lot cheaper than stuff like ADSL, as there are no cables to worry about, and the base station towers cover a very large area of up to 50km radius - 2500 square km. If you are very far from a WiMax tower you will experience a slightly slower connection speed.

WiMax operates at high frequencies. There are 2 main bands: 2 - 11 GHz for Non-Line-Of-Sight (ie laptops) called

NLOS and then 10 - 66 GHz for Line-Of-Sight (LOS) (ie Desktops, non-mobile stuff) which will have to use an outside aerial unless they are very close to the WiMax tower.

WiMax is closely controlled and equipment has to be certified by the WiMax Forum. The standard is called 802.16-2004 of which the 2 variants are 802.16d (

LOS PCs/fixed) and 802.16e (NLOS laptops/mobile). It is often referred to as a MAN (Metropolitan Area Network) because one base station tower can cover a whole city.

It is quite a new technology, and there is a bit of delay in getting licenses issued here in South Africa. Telkom, Vodacom and MTN have WiMax installed at some places already, but they are unable to fully market the product because licences to do so have not been issued because the authorities are still figuring out the scope of the licensing process. Sentech is due to roll out a WiMax network to Post Offices and Dinaledi schools in the rural areas. These are schools that concentrate on Maths and Science, and hope to address the skills shortage in the country in these fields.

Some more technical details.

WiMax can use 2 types of duplexing: TDD (Time Division Duplex) or FDD (Frequency Division Duplex)

Modulation is probably going to be OFDM (Orthoganal Frequency Division Multiplexing) and OFDMA (Orthoganal Frequency Division Multiple Access) for mobile/laptop users.






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