IEEE Circuits and Systems Magazine - Q2 2019 - 56

We compare three array architectures when their design
parameters are optimized to meet the spectral efficiency targets in three representative 5G-NR use cases. The
results show that digital architecture is the most efficient
in terms of power and IC area. The key intuition behind
this finding is that digital array architecture can effectively save system power and area by levering high multiplexing gains due to digital precoding of multiple spatial streams, which effectively reduces requirements for
array size, transmit power, and hardware specifications
of the RF-chains. On the other hand, the hybrid architectures require additional power to support more simultaneous spatial beams. We reveal that the bottleneck of hybrid architectures is the RF signal distribution network in
RF beamforming stage. Furthermore, additional transmit
power is required in sub-array architecture to compensate for the array splitting loss.
Acknowledgment
This work is partially supported by National Science Foundation through grant 1718742. This work was also supported in part by the ComSenTer and CONIX Research
Center, two of six centers in JUMP, a Semiconductor Research Corporation (SRC) program sponsored by DARPA.
Authors would like to acknowledge Dr. Jefferey Lee and
Dr. Yan Zhao for their helpful comments and discussions.
Han Yan (S'13) received the B. E. degree
in Information Engineering from Zhejiang University, Hangzhou, China in 2013,
and the M.S. degree in Electrical Engineering from University of California,
Los Angeles, CA, USA in 2015. He is currently pursuing the Ph.D. at the University of California,
Los Angeles, CA, USA. His research interests includes signal processing for millimeter-wave communications, cognitive radio, and coordinated wireless communications.
Sridhar Ramesh (M'01) is Senior Director in Communication System Engineering at Maxlinear, developing architectures and algorithms for broadband
communications IC's and systems. He
received a B.Tech. degree in Electronics
and Communications Engineering from the Indian Institute of Technology, Madras, India, an M.E. degree in
Electrical Communication Engg from the Indian Institute
of Science, Bangalore, India, and a Ph.D. degree in Computer Science from North Carolina State University.
Timothy Gallagher (M'05) received the B.S. degree in
electrical engineering and computer science from the
University of Colorado, Boulder, and the M.S. degree in
56

ieee circuits AND sYstems mAGAziNe

electrical engineering, specializing in signal processing,
from the University of Southern California, Los Angeles, in
1982 and 1988, respectively. He is currently a Vice President
of communication systems with MaxLinear, Inc., Carlsbad,
CA. His current research interests include efficient implementation of signal processing algorithms and digital communication.
Curtis Ling (SM'02) received the B.S. degree in electrical
engineering from the California Institute of Technology,
Pasadena, and the M.S. and Ph.D. degrees in electrical engineering from the University of Michigan, Ann Arbor. He is a
Co-Founder of MaxLinear, Inc., Carlsbad, CA, where he has
been the Chief Technical Officer since April 2006, was the
Chief Financial Officer from 2004 to 2006, and was a Consultant from 2003 to 2004. He was a Principal Engineer with
Silicon Wave, Inc., from 1999 to 2003. He was a Professor
with the Hong Kong University of Science and Technology,
Hong Kong, from 1993 to 1999.
Danijela Cabric is Professor in Electrical and Computer Engineering at University of California, Los Angeles. She
earned MS degree in Electrical Engineering in 2001, UCLA and Ph.D. in Electrical Engineering in 2007, UC Berkeley,
Dr. Cabric received the Samueli Fellowship in 2008, the
Okawa Foundation Research Grant in 2009, Hellman Fellowship in 2012 and the National Science Foundation Faculty Early Career Development (CAREER) Award in 2012.
She is now Associated Editor of IEEE Transactions of
Cognitive Communications and Networking and IEEE
Transactions of Wireless Communications. Her research
interests include novel radio architecture, signal processing, and networking techniques for cognitive radio,
5G and massive MIMO systems. She is Senior Member of
IEEE and IEEE ComSoc Distinguished Lecturer.
References
[1] F. Boccardi, R. W. Heath, A. Lozano, T. L. Marzetta, and P. Popovski,
"Five disruptive technology directions for 5G," IEEE Commun. Mag., vol.
52, no. 2, pp. 74-80, Feb. 2014.
[2] Z. Pi and F. Khan, "An introduction to millimeter-wave mobile broadband systems," IEEE Commun. Mag., vol. 49, no. 6, pp. 101-107, June 2011.
[3] FCC, Fact sheet: spectrum frontiers proposal to identify, open up
vast amounts of new high-band spectrum for next generation (5G) wireless broadband, July 2016. [Online]. Available: https://apps.fcc.gov/
edocs_public/attachmatch/DOC-339990A1.pdf
[4] J. G. Andrews et al., "What will 5G be?" IEEE J. Sel. Areas Commun.,
vol. 32, no. 6, pp. 1065-1082, June 2014.
[5] A. Ghosh et al., "Millimeter-wave enhanced local area systems: a
high-data-rate approach for future wireless networks," IEEE J. Sel. Areas
Commun., vol. 32, no. 6, pp. 1152-1163, June 2014.
[6] S. Rangan, T. S. Rappaport, and E. Erkip, "Millimeter-wave cellular
wireless networks: potentials and challenges," Proc. IEEE, vol. 102,
no. 3, pp. 366-385, Mar. 2014.
[7] T. S. Rappaport et al., "Millimeter wave mobile communications for
5G cellular: it will work!" IEEE Access, vol. 1, pp. 335-349, May 2013. doi:
10.1109/ACCESS.2013.2260813
secoND QuArter 2019

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IEEE Circuits and Systems Magazine - Q2 2019

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