In recent years,
wireless communication
has become extremely
important throughout the
world and in particular
for Hong Kong and China.
At CenWIT, HKUST, we
have major research and
development efforts, but
not limited to, the
following wireless
communication areas:
Adaptive MIMO signal
processing
Array signal
processing
Cognitive radio
Convex optimization
theory for
communication
systems
Cooperative
communication
systems
Cross-layer design,
adaptation, and
optimization for
wireless networks
with QoS
provisioning
Game theory for
ad-hoc networks
Information theory
for communication
systems
MIMO antenna design
MIMO-OFDM systems
Multiuser MIMO
communications
RFID
Wideband MIMO
channel
characterisation
Ongoing Research
and Development Projects
CenWIT has many on-going
research and development projects that are actively
participated in by faculty and students:
Design and
performance analysis
of the radio
interface for
Beyond 3G (B3G)
systems;
Research and
standardization on
key technologies of
IEEE802.22 (Wireless
Regional Area
Networks, WRAN)
standard;
Research and
standardization on
key technologies of
IEEE802.16m (Mobile
WiMax)
standard;
Algorithm design and
analysis for
Practical MIMO
(P-MIMO)
systems;
Advanced algorithm
and implementation
for MBOA PHY layer
of
Ultra-wide band
(UWB)
systems;
Handset
MIMO antenna
(A-MIMO)
testing and design;
Develop enabling
technologies for
low-cost single-chip
CMOS passive
RFID tags
and readers; and
Re-configurable OFDM
(R-OFDM)
radio baseband VLSI
architecture design.
Abstract:
Cooperative diversity has been recently proposed as a
way to form distributed antenna arrays that improve
error
performance and capacity. In this paper, a bandwidth
efficient cooperative diversity scheme is proposed for
half-duplex amplifyand-forward wireless relay networks.
By employing a signal space diversity technique and
allowing the source node to keep on transmitting over
the whole duration of the cooperation frame, the
proposed cooperative scheme is proved to be able to
achieve both full-rate and full-diversity
simultaneously. Diversity analysis shows that the
achievable diversity gain is M + 1, where M is the
number of relay nodes. Moreover, a power allocation
scheme is proposed to maximize the coding gain under a
total power constraint. Simulation results are shown to
demonstrate the full-rate and full-diversity of the
proposed scheme.
2007 IEEE
International Conference on Communications (ICC):
Best Paper Award
Title:
Cooperative Concatenated Coding for Wireless
Systems
Abstract:
Cooperative transmission has been of growing interest
recently where users take advantage of each other's
resources for better overall performance. In this paper,
coded cooperation for wireless networks is considered
and a novel cooperative concatenated coding strategy is
proposed. In contrast to previous works, this scheme
features additional coding benefits other than spatial
diversity. Specifically, we show that remarkable error
rate reduction can be achieved even when the receive SNR
of all cooperating users is maintained at a specific
level. The idea of interleaver gain of concatenated
codes is exploited and it is shown that the error rate
decreases dramatically with the number of cooperating
nodes. Multiple cooperating users with unequal message
sizes can also be supported easily and a
reduced-complexity cooperative encoding strcuture is
provided for good inter-user channels. Code design
criteria are also investigated, as well as, the
performance under various data-block sizes and number of
cooperating users.
2006 IEEE International Conference on Communications (ICC):
Best Paper Award
Title: A
Cross Layer Method for Interference Cancellation
and Network Coding in Wireless Networks
Abstract:
Multi-hop wireless networks are expected to play
an important role in the next-generation
wireless systems. One of the central problems in
such networks is the network capacity. This
paper presents a novel cross layer method for
interference cancellation and network coding,
which significantly increases the capacity of
multi-hop wireless networks. We decompose the
multi-hop network into a cell-like sub-network,
which we refer to as a wireless switching
network. In the proposed approach, multiple
nodes, each with its self-information, can
communicate via relay nodes. The nodes' self
information can then be utilized to cancel the
multiuser interference and enable network
coding. We shall derive the capacity regions of
two cross layer strategies, and show that they
are larger than that of the traditional
broadcast channel.
2006 IEEE
International Conference on Acoustics, Speech, and
Signal Processing (ICASSP): Best Student Paper Award
Title:
Potential Games: A Framework for Vector Power
Control Problems with Coupled Constraints
Abstract:
In this paper, we propose a unified framework,
based on the emergent potential games to deal
with a variety of network resource allocation
problems. We generalize the existing results on
potential games to the cases where there exists
coupling among the (possibly vector) strategies
of all players. We derive sufficient conditions
for the existence and uniqueness of the Nash
Equilibrium, and provide different distributed
algorithms along their convergence properties.
Using this new framework, we then show that many
power control problems (standard and
non-standard) with coupled constraints among the
users, can be naturally formulated as potential
games, and hence, efficiently solved. Finally,
we point out an interesting interplay existing
between potential games, classical optimization
theory, and Lyapunov stability theory.
2002 SITA
International Symposium on Information Theory and
its Applications (ISITA): Paper Award for Young
Researchers
Title: A
Simple Effective Iterative Detection Scheme for
Bit-Interleaved Coded Modulation
Abstract:
Bit-interleaved coded modulation (BICM) with
iterative detection (ID) is effective for fading
channels because it can simultaneously realize
high diversity and large Euclidean distance. Two
types of iterative detection schemes, based on
hard decision feedback (HDP) and soft decision
feedback (SDF) respectively, have recently been
investigated for BICM. While the HDF/ID scheme
exhibits significant performance degradation
relative to the SDF/ID scheme, it has a much
lower implementation complexity. In this work,
we propose a novel BICM-ID scheme based on the
so-called uniform soft decision feedback (USDF).
Compared with HDF/ID, the USDF/ID scheme is only
slightly more complicated but has a much less
performance degradation relative to SDF/ID.
Thus, the proposed BICM-USDF/ID scheme is rather
attractive for practical wireless applications.
2000 IEEE Vehicular
Technology Conference (VTC) Spring: VTS Japan
Chapter Award
Title:
Adaptive Spatial-Subcarrier Trellis Coded MQAM
and Power Optimization for OFDM Transmission
Abstract:
Recently, space-time coding or coded modulation
has demonstrated that significant increases in
system capacity and performance can be achieved
by incorporating multiple antennas at the
receiver. In this paper, we propose an adaptive
spatial-subcarrier trellis coded modulation
using MQAM for orthogonal frequency division
multiplexing (OFDM) transmission by using
instantaneous channel state information and
employing multiple antennas at both the
transmitter and the receiver. In particular, our
objective is to minimize the total transmit
power required for each OFDM transmission, by
optimizing the power allocation, code rate and
modulation scheme in each spatial-subcarrier
channel, while maintaining a given data rate and
bit error probability. To illustrate the
potential of our proposed system, Monte Carlo
simulation results are provided.
2000 IEEE Antennas
and Propagation Symposium: 2nd Winner Up of the
Student Paper Contest
Title:
A Planar Diversity Antenna for Wireless Handsets
Abstract:
We introduce a compact integrated antenna that
has two feed ports with more than 20dB isolation
between them. The significance of the design is
that it can be utilized in compact wireless
communication handsets to provide diversity
signals or act as a duplexer allowing the
receive and transmit signals to be well
isolated. The antenna design is based on merging
two patch antennas together and experimental
results at 2220MHz include radiation patterns,
S-parameters, and signal correlations between
ports. These demonstrate that the envelope
cross-correlation between ports is less than 0.1
making the antenna suitable for diversity
applications.
