Princeton University

School of Engineering & Applied Science

Massive MIMO: Channel State Information Isn’t Everything, It’s the Only Thing!

Thomas L. Marzetta
E-Quad, B205
Tuesday, April 28, 2015 - 4:30pm to 5:30pm

Abstract:  Massive MIMO promises spectacular spectral efficiency improvements over today's wireless technology. It utilizes large numbers of small, low-power, individually controlled antennas selectively to transmit and receive message-bearing power to and from a multiplicity of user terminals, all within the same time/frequency resources. The acquisition of channel state information (CSI) by the base station via direct measurements is both the enabler for the multiplexing, and - in so far as is known - a fundamental limitation on the number of mobile users that can be multiplexed. Short of a huge breakthrough, the forced re-use of pilot sequences that results in coherent inter-cell interference cannot be eliminated, but only mitigated by, for example, adopting a pilot reuse factor greater than one. We find that in dense urban environments, the relatively small cell size combined with low user mobility dictates pilot reuse seven. Conversely in rural deployments pilot reuse three is optimal. Despite the extra training overhead, when max-min power control is utilized, Massive MIMO can provide unprecedented throughput to all users with high reliability everywhere in the cell.
Bio:  Thomas Marzetta is the originator of Massive MIMO. He is Group Leader of Large Scale Antenna Systems at Bell Labs, Alcatel-Lucent and Co-Head of their FutureX Massive MIMO project.  Dr. Marzetta was born in Washington, D.C. He received the PhD and SB in Electrical Engineering from Massachusetts Institute of Technology in 1978 and 1972, and the MS in Systems Engineering from University of Pennsylvania in 1973. He worked for Schlumberger-Doll Research in petroleum exploration and for Nichols Research Corporation in defense research before joining Bell Labs in 1995 where he served as the Director of the Communications and Statistical Sciences Department within the former Math Center. Currently Dr. Marzetta serves as Coordinator of the GreenTouch Consortium's Large Scale Antenna Systems Project, and as Member of the Advisory Board of MAMMOET (Massive MIMO for Efficient Transmission), an EU-sponsored FP7 project.  For his achievements in Massive MIMO he has received the 2015 IEEE W. R. G. Baker Award and the 2014 Thomas Alva Edison Patent Award, among others. He was elected a Fellow of the IEEE in 2003, and he became a Bell Labs Fellow in 2014. In May 2015 he will receive an Honorary Doctorate from Linköping University.