2005-09-05

Science: 4G by 2010?

Cellphones capable of transmitting data at blistering speeds have been demonstrated by 'NTT DoCoMo' in Japan. In experiments, prototype phones were used to view 32 high definition video streams, while travelling in an car at 20 kilometres per hour. Officials from 'NTT DoCoMo' say the cellphones could receive data at 100 megabits per second on the move and at up to one gigabit per second while static. At this rate, an entire 'DVD' (Digital Versatile Disc) could be downloaded within a minute. 'DoCoMo's' current '3G' (third generation) cellphone 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 cellphone 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. For example, 'MIMO' could enable a cellphone to receive data from more than one base station in range. The activities 'are technically impressive,' says Mr. Lajos Hanzo, a communications expert at Southampton University in the UK. But Mr.Hanzo said 'NTT DoCoMo' will need assistance from other phone companies if it is to kick-start '4G' uptake.
'In today's world nobody can go it alone,' he says. 'And hence any standard proposal must be internationally ratified, which has not as yet take place."'
Some countries have already begun cooperating on such standards; Japan and China signed a memorandum on 2005-08-24 to work together on '4G'. 'NTT DoCoMo' hopes to launch a commercial '4G' network by 2010. ''4G' prototypes reach blistering speeds', Will Knight, New Scientist/Yahoo Business News, 2005-09-05, Mo 15:00

0 Comments:

Post a Comment

Links to this post:

Create a Link

<< Home