PhD Qualifying Examination


"Resource Allocation in Future Generation MIMO WLAN"

Mr. Wenqi ZHU


Abstract:

Resource allocation in future generation Multiple Input Multiple Output
(MIMO) wireless local area networks (WLANs) has been identified as one
key approach to improve their performance, functionality,  as well as
their reliability. Unlike the current single antenna WLAN products, MIMO
takes advantage of spatial multiplexing. In particular,  it can explore
the random multipath propagation to mitigate numerous problems previously
associated with SISO WLANs.

This survey report introduces the background knowledge and the related
techniques in MIMO, including the channel models, the waterfilling
technology with full channel status information in transmitter (CSIT) and
some practical consideration according to the correlated factors about
channel.

Then the survey focuses on the technology in the physical layer. The
concept of beamforming, diversity and spatial multiplexing are introduced
in detail. In addition, the tradeoffs between diversity and spatial
multiplexing in different situations have been described numerically and
the relationships are shown respectively. The theoretical relationship
between the spatial multiplexing gain and diversity reveals the essential
connection between the utilization of each of these two aspects in the
physical layer. As a result, this relationship demonstrates the tradeoff
in designing and evaluating the various schemes in MIMO.

Finally, several schemes are described in this paper from different
control granularities: switching between diversity and spatial
multiplexing or selecting the best subset of antennas for the
transmission in spatial multiplexing. From the perspective of the control
criterion, this survey introduces several factors which are used in the
scheme to make the best resource allocation decision, including the
properties of channel condition, the error probability, and the receiver
SNR. Furthermore, the MAC layer protocol can join into the decision
combined with the adaptation in the physical layer as a cross layer
design problem. A rate adaptive MAC protocol for MIMO-based wireless
network (MIMAC) is presented in this paper as well.


Date:     		Thursday, 19 January 2006

Time:                   4:00p.m.-6:00p.m.

Venue:                  Room 2503
			lifts 25-26

Committee Members:      Prof. Mounir Hamdi (Supervisor)
			Dr. Zonghua Gu (Chairperson)
			Dr. Brahim Bensaou
			Dr. Gary Chan


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