Cooperative Interference Management in Multi-Cell Downlink Beamforming

Speaker:	Dr. Shuguang CUI
		Department of Electrical and Computer Engineering
		Texas A&M University

Title:		"Cooperative Interference Management in Multi-Cell
		 Downlink Beamforming"

Date:		Thursday, 7 January, 2010

Time:		3:00pm - 4:00pm

Venue:		Room 3412 (via lifts 17/18), HKUST

Abstract:

We study the downlink beamforming for a multi-cell system, where multiple
base stations (BSs) each with multiple antennas cooperatively design their
respective transmit beamforming vectors to optimize the overall system
performance. It is assumed that all mobile stations (MSs) are equipped
with a single antenna each, and there is one active MS in each cell at one
time. Accordingly, the system of interest can be modeled by a
multiple-input single-output (MISO) Gaussian interference channel (IC),
termed as MISO-IC, with interference treated as additive Gaussian noise.
We are interested in designing a multi-cell cooperative downlink
beamforming scheme to achieve different rate-tuples for active MSs on the
Pareto boundary of the achievable rate region for the MISO-IC, which is in
general a non-convex problem due to the coupled signal structure. By
exploring the relationship between the MISO-IC and the cognitive radio
(CR) MISO channel, we show that each Pareto-boundary rate-tuple of the
MISO-IC can be achieved in a decentralized manner when each of the MSs
attains its own channel capacity subject to a certain set of
interference-power constraints (also known as interference-temperature
constraints in the CR system) at the other MS receivers. Furthermore, we
show that this result leads to a decentralized algorithm for implementing
the multi-cell cooperative downlink beamforming, where all different pairs
of BSs independently search for their mutually desirable
interference-temperature constraints, under which their respective
beamforming vectors are optimized to maximize the individual transmit
rates. It is shown that this algorithm guarantees to improve the rates for
a given pair of BSs at each iteration with those for the other BSs
unaffected, and converges when there are no further incentives for all the
BSs to adjust their mutual interference-temperature constraints.

(This is based on a joint work with Dr. Rui Zhang from I^2R, A-Star,
Singapore.)


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Biography:

Shuguang Cui received his Ph.D in Electrical Engineering from Stanford
University, California, USA, in 2005. He is now working as an assistant
professor in Electrical and Computer Engineering at the Texas A&M
University, College Station, TX. His current research interests include
resource allocation for constrained networks, network information theory,
statistical signal processing, and general communication theories. He was
a recipient of the NSERC fellowship from the National Science and
Engineering Research Council of Canada, the Canadian Wireless
Telecommunications Association (CWTA) scholarship, the CROWNCOM'07 and
WCSP'10 best paper awards, three NSF grant awards, and three DoD grant
awards. He has been serving as the TPC chairs for the 2007 IEEE
Communication Theory Workshop, the ICC'08 Communication Theory Symposium,
and the GLOBECOM'10 Communication Theory Symposium. He has also been
serving as the associate editors for the IEEE Communication Letters and
IEEE Transactions on Vehicular Technology, and the elected member for IEEE
Signal Processing Society SPCOM Technical Committee (2009~2012).