New MIMO-type antennas, developed by Alcatel-Lucent, have been used in live field trials to demonstrate much improved uplink performance regardless of whether the user was close to the centre of an LTE cell or at its outer edge. The tests took place in Berlin, Germany, with the cooperation of Deutsche Telekom Labs, the Fraunhofer Heinrich-Hertz Institut, and antenna supplier Kathrein.
The technology under test--Coordinated Multipoint Transmission (CoMP)--was said by Alca-Lu to take advantage of MIMO (Multiple Input-Multiple Output) techniques pioneered by Bell Labs, now part of Alca-Lu. The company said that uplink data rates faster than 5Mbps were observed for the vast majority of locations even at the edges of the LTE cell.
Those involved with the tests said that the configuration differed from that of basic MIMO with CoMP interconnecting antennas deployed at a number of sites that were in proximity to one another.
The test conditions saw transmissions from the mobile devices being received by two active remote radio heads deployed on two buildings located 500m from one another, then forwarded across an optical fibre link to a central unit comprising the modem and controller elements of an Alca-Lu LTE base station (eNodeB). The signals were then combined with one another to increase the strength of the signal. The tight coordination of the transmission and reception of signals at these multiple access points was said to reduce interference.
"The results we have achieved with this new transmission technology are built on our world-leading multi-antenna wireless research," said Gee Rittenhouse, head of Bell Labs Research. "In the future as LTE networks become widely deployed we expect that CoMP will help enable our customers to meet the next wave of demand from users who expect to access all sorts of exciting high-bandwidth applications with their mobile phones."
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