4G Technology To Reach New Frontiers

THE mobile phone has become the Swiss army knife of consumer electronics, becoming by turn a games machine, emailer, camera, or news browser. Heck, you can even talk to people on them. This feature creep has gone so far it's tempting to think it cannot go much further. But new technologies on the horizon in Japan, the market most infatuated with the mobile, suggest the idea of a phone as a do-everything gadget still has a lot of mileage in it. NTT DoComo demonstrates cellphones capable of transmitting data at blistering speeds.In experiments, prototype phones were used to view 32 high definition video streams,while travelling in an automobile at 20 kilometres per hour. Officials from NTT DoCoMo say the phones could receive data at 100 megabits per second on the move and at up to a gigabit per second while static. At this rate, an entire DVD could be downloaded within a minute. DoCoMo's current 3G phone network offers download speeds of 384 kilobits per second and upload speeds of 129 kilobits per second. The technology behind NTT DoCoMo's high-speed phone network remains experimental, but the 4G tests used a method called Variable-Spreading-Factor Spread Orthogonal Frequency Division Multiplexing (VSF-Spread OFDM), which increases downlink speeds by using multiple radio frequencies to send the same data stream. Another wireless networking trick, called multiple-input-multiple-output (MIMO) multiplexing, was used to send data via various routes across a network, in order to further increase data capacity.MIMO could enable a cellphone to receive data from more than one base station in range. NTT DoCoMo hopes to launch a commercial 4G network by 2010.