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... but before 4G?
>> 10/4/00"ENGINEERS LOOK BEYOND 3G TO BOOST DATA RATES"
Peter Clarke
Electronic Times
02 October 2000
Engineers meeting within 3GPP, the partnership of standards setting bodies for communications, are looking to create an enhanced version of the 3G wideband CDMA radio interface that will boost data rates to 8Mbit/s.
Conventional WCDMA can support data rates of 384kbit/s in mobile environments and up to 2Mbit/s in stationary situations.
According to Ericsson executives, demand for multiple broadband channels carrying video and multimedia services, and the need to aggregate those services together, could require enhanced data rates long before mobile networks begin to migrate to 4G architectures, expected to happen around 2010.
To get to enhanced-WCDMA, Hakan Eriksson, general manager of Ericsson corporate research, said: "We're looking towards the use of a different modulation scheme that uses more efficient encoding, but you can't provide this over an entire cell area."
Conventional WCDMA uses QPSK modulation on 5MHz spaced carrier channels at around 2GHz.
"It would be done with the basic carrier frequency staying at 5MHz," said Eriksson, adding that the 8Mbit/s 3G data rate could be introduced in the second half of the decade but ahead of a move to 4G in about 2010.
Jan Uddenfeldt, chief technology officer for Ericsson, stressed that it was important not to raise expectations about having 8Mbit/s enhanced-WCDMA channels available all the time at every terminal.
"It depends if you get a good radio signal. You can't keep that data rate all the time. So it might apply indoors or for residential use," he said.
Uddenfeldt explained that enhanced-WCDMA might be used as wireless local loop system, connecting a base station in a carrier's network to a residential base station that would then support multiple mobile terminals around the home or office through Bluetooth wireless connections.
Because the communicating basestations are at fixed positions the radio channel could be optimised to secure the 8Mbit/s data rate but the channel would also be used for aggregated traffic, Uddenfeldt said.
Walter Tuttlebee, director of the UK government-supported Virtual Centre for Excellence in mobile and personal communications, said that for enhanced WCDMA some form of m-ary phase shift keying modulation might be favoured to provide backwards compatibility with the current QPSK modulation.
OFDM [orthogonal frequency domain multiplex] has been proposed for 4G but would be a radical change from current designs and had been rejected for 3G.
Peter Clarke is European correspondent of our US sister publication EE Times.
(C) 2000 Electronics Times via Bell&Howell Information and Learning Company; All Rights Reserved. <<
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