Researchers at Alcatel-Lucent’s Bell Laboratories are developing a new Coordinated Multipoint Transmission (CoMP) technology aimed at increasing data transmission rates and ensuring consistent service quality and throughput on LTE as well as on 3G networks. 
The performance gains are achieved by coordinating and combining signals from multiple antennas. Unlike with existing MIMO (Multiple Input-Multiple Output) approaches, CoMP leverages multiple access points — a technique termed Network MIMO. Bell Labs, which pioneered MIMO, said its development of Network MIMO also reflects a commitment to open innovation and serves as a clear demonstration of the benefits that result.
Live field tests of CoMP have been conducted in the downtown areas of Berlin in cooperation with Deutsche Telekom Laboratories, the Fraunhofer Heinrich-Hertz Institut, and antenna supplier Kathrein. The tests were part of a joint research project sponsored by the German Ministry for Education and Research (BMBF) called Enablers for Ambient Services and Systems (EASY-C).
During the tests, signals transmitted from mobile devices were received by two active remote radio heads deployed on two buildings located 500m from one another, then forwarded across an optical fiber link to a central unit comprising the modem and controller elements of an Alcatel-Lucent LTE base station (eNodeB). The signals were then combined with one another to increase the strength of the signal. Transmissions between mobile devices and base stations during the field tests made use of the 2.6 GHz frequency band, which is expected to be the predominant band for introduction of commercial LTE services in Europe.
Alcatel-Lucent said these tests showcased Coordinated Multipoint Transmission’s key benefits:
- Helps improve bandwidth scalability by boosting transmission rates not only in the connection from the network to the user’s mobile device (downlink), but from the mobile device to the network (uplink).
- Improves quality of service by demonstrating consistently high transmission rates on the uplink from the phone to the network, even at the edges of a “cell” where transmission quality is typically poor and difficult to maintain; data rates greater than 5Mbps were observed for the vast majority of locations.
- Maximizes the use of existing network infrastructure to achieve these higher transmission speeds without necessarily requiring deployment of additional antennas.
“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.”http://www.alcatel-lucent.com
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- In June 2009, Germany’s Project EASY-C announced the first demonstration of a multi-cell cooperative coherent downlink transmission from two base stations to two mobile terminals. This test was performed by TU Dresden. Project EASY-C has a number of industry and academic partners. Key findings are posted on their website.
