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WiMax Info.

Everything you always wanted to know about WiMax

WiMax, 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.

All broadcasters world wide are in the process of going digital. This means that the old system of receiving a television broadcast in your lounge off an aerial on a normal TV will soon be over. The old analogue TV transmitters will soon be switched off, after being replaced by new digital transmitters.

To the consumer, or average viewer, the effect is that they will either need to buy a set top box, which will take the digital signal and convert it to analogue so that their old TV set will work, or they will have to buy a new TV set with a digital tuner. NOTE: Not all new TV sets HAVE a digital tuner, even if they have fancy attributes like HDMI, or digital ready, or whatever. Make sure thay have a digital tuner and an aerial socket where you can plug your old aerial cable into.

NEWS ON THE DIGITAL MIGRATION IN SOUTH AFRICA

South African government authorities have finally agreed on the DVB-T2 European standard after years of faffing about, bribery and corruption. The T2 standard is better than the original DVB-T standard originally proposed, as it can take up to 15 channels per multiplex (aka Transmitter) whereas the T1 could only handle 8.

Installation of the new digital transmitters by Sentech is going ahead. The main metropolitan areas have already been done (albeit with DVB-T so some retrofitting is being done) and some 30% of South African population coverage is being claimed. Installations in the rural areas are now in full swing, with the latest site being Fort Mistake, which is between Newcastle and Ladysmith in KwaZulu Natal. At this site two water cooled 5 kilowatt Rohde & Schwarz digital transmitters have been installed (see pic) with their associated UPS's, Program Input Equipment, Satellite and GPS receivers and water cooling systems. This site has not yet been switched on, but hopes are that switch on will be within the next month or two.

These 5KW transmitters, because of the large number of carriers transmitted, are equivalent to a 20KW analogue transmitter. This single transmitter can transmit either 15 standard TV channels, or 4 HD channels, or a large number of music channels, or a combination of all the above, eg 2 HD channels, 5 standard TV channels, and 10 music channels.

These can then all be received by the public using their existing TV and aerial, plus a set top box - which should be retailing in the shops soon for about R800. Hopefully this price should drop over time as economies of scale are acheived. (ie so many are sold that manufacturer can make a profit at a lower price.)

Also, flat screen TVs are now appearing in the shops with a digital tuner, which can receive all these channels without a set top box.