Ericsson takes LTE to the street

Ericsson has managed to achieve rates in excess of 100M bps (bits per second) with next-generation mobile technology LTE (Long Term Evolution) during recent field trials.

LTE is pitched as a successor to the 3G (third generation) mobile services such as the European UMTS (Universal Mobile Telecommunications System) and similar wide-band CDMA (W-CDMA) services.

Ericsson's goal in the field trials was to show that LTE works all the way from the base station to the terminal. "It's always easy to say that you can get a certain speed in a lab environment, but here we have used real antennas and real distances to the terminals, and also in a moving vehicle," said Lars Tilly, head of research at Ericsson Mobile Platforms.

Using four transmit streams (the maximum number supported in the LTE standard), four receive antennas and bandwidth of 10 MHz, the measured peak rates exceeded 130M bps. This translates into approximately 260M bps, given the maximum bandwidth of 20 MHz, according to an article in Ericsson Review.

"Not everyone will be able to get 100M bps. You need pretty good conditions for it to work, and you need to be relatively close to the base stations, a couple of hundred meters," said Tilly.

The company also evaluated application-level performance using two transmit and two receive antennas, and the TCP (Transmission Control Protocol) bit rate was more than 40M bps at least 50 percent of the time and more than 100M bps at least 10 percent of the time along a test route, which a majority of the time stayed within 1 kilometer from the test site.

The test also shows how important it is to use MIMO (Multiple-Input Multiple-Output) to get the most out of LTE. Using four transmit and receive antennas increase performance by a factor of three compared to a basic setup. But at the same time Ericsson warns that MIMO-related gains are strongly dependent on radio conditions.

All the major telecommunications equipment vendors are currently working at full speed to get LTE out the door, according to Martin Gutberlet, analyst at Gartner.

He isn't worried about the base stations. Instead it's the lack of access to the necessary spectrum, which still hasn't been handed out in many European countries, including U.K., France and Germany, that could lead to delays, according to Gutberlet.

Ericsson expects that the first commercial LTE network will go live in the fourth quarter of 2009, according to a spokeswoman

IDG News Service

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