Research Topics
RESEARCH TOPICS of the
COMMUNICATIONS GROUP
Members of the CSL
Communications Group conduct research in the
general areas of communication systems and networks, error-control and
modulation coding, information theory, and source coding. Specific
research topics currently being pursued are listed below.
WIRELESS COMMUNICATION SYSTEMS
Design and analysis of robust communication systems that efficiently
utilize radio bandwidth. Parallel and sequential methods for
acquisition of synchronization, and the use of multiuser detection
methods for interference suppression in direct-sequence code division
multiple access (CDMA) systems. Adaptive interference suppression
methods for acquisition and demodulation in direct-sequence CDMA
systems. Adaptive coding, iterated decoding, and retransmission
techniques in direct-sequence and frequency-hop CDMA systems. Design
and performance analysis of adaptive mechanisms over channels with
fading, multipath, and time-varying interference. Adaptive antenna
arrays for interference suppression.
COMMUNICATION NETWORKS
Investigation of routing, congestion, and transmission control
mechanisms for networks ranging from wireless networks (such as
multihop packet radio networks, wireless local area networks, personal
communications networks and cellular telephony networks) to high-speed
guided media networks (such as fiber-optic ATM networks and multi-
processor computer networks.) Performance of wireless networks under
changes in traffic, interference, and connectivity. Interaction
between channel measurements and network protocols; support for
multimedia traffic. Methods to provide service guarantees for multiple
classes of traffic in guided media networks. Interfaces between
wireless and guided media networks. Tools used include stochastic
modeling and analysis, optimization, computer simulations, estimation
theory, combinatorics, and information theory.
THEORY AND APPLICATIONS OF ERROR-CONTROL CODES
Design of efficient decoding algorithms for error-control codes;
hardware and software implementations of error-control coding systems.
Applications of error-control codes in digital communication and
storage systems. Design of Euclidean-space codes and decoders for these
codes, based on the theory of lattices and sphere packings. Development
of codes and algorithms based on algebraic geometry and commutative
algebra. Block and tree codes for soft-decision channels.
MULTIDIMENSIONAL INFORMATION AND COMMUNICATION THEORY
Design of multidimensional communication waveforms for the two and
three dimensional optical or magnetic recording channels. Capacity of
multidimensional channels, two-dimensional data modulation codes and
data transmission codes.
SOURCE CODING
Investigation of the design and theoretical performance of data
compression algorithms. Study of universal lossy coding (where the
source is unknown a priori), noisy channel quantization, noisy source
quantization, empirical design techniques, and convergence rates of
algorithms. Very low complexity systems for power-constrained real-
time applications such as speech and image coding.