A/Prof. Steve Weller
Research
Current research projects Dynamical systems and iterative decoding of low-density parity-check codes
2007-2009 ARC Discovery Project Grant DP0771131, $210K
Chief Investigator: Dr. Steve Weller
Partner Investigator: Dr. Chris Kellett
Modern communications is based on the premise that information represented digitally can be reliably transmitted, stored and reproduced. After some 50 years of steady progress in designing the error control codes needed to ensure integrity of data transmission and storage, breakthroughs in the late-1990s have used principles of iteration and feedback to push the theoretically achievable performance of low-density parity-check (LDPC) codes close to fundamental limits, though practical codes fall short of these limits. This project aims to apply techniques from the theory of nonlinear dynamical systems to analyse and design practical iterative decoding algorithms for next-generation digital communications based on LDPC codes.
New methods and microelectronics for wireless
communication systems
2005-2009 ARC Linkage Project Grant LP0561092, $970K
Chief Investigators: A/Prof. Brett Ninness and Dr. Steve Weller
Partner Investigators: Dr. Graeme Woodward, Dr. Mark Bickerstaff and Dr.
Adriel Kind
Industry Linkage Partner: Agere Systems Australia
Australian Postgraduate Award Industry (APAI) scholarships: Mr. Ian Griffiths and Mr. Alan Murray
Global demand for high quality wireless communications poses
significant challenges. The so-called "physical layer" is crucial, as
this is where the vagaries of the wireless channel, including
interference and limited bandwidth, are mitigated by sophisticated
signal processing. This project will conduct applied research to meet
these physical layer challenges, providing solutions that feed
directly into next generation wireless communication
systems. Uniquely, this project focuses on the transfer of research
from theoretical genesis, through to realisation of silicon integrated
circuit "chips". This will maximise both the impact of the research
and the potential for significant national economic benefits to
accrue.
Structured low-density parity-check codes for next-generation
communications
2004-2006 ARC Discovery Project Grant DP0449627, $257K
Chief Investigator: Dr. Steven R. Weller
Australian Postdoctoral Fellowship (APD): Dr. Sarah Johnson
The promise of essentially error-free information transmission is a
cornerstone of digital communications. Next-generation applications
demand increasingly effective error correction, yet at the same time
traditional systems fall well short of fundamental capacity limits
established some fifty years ago. Exciting breakthroughs were made in
the mid-1990s, when capacity-approaching low-density parity-check
(LDPC) coding schemes were discovered, along with other codes on
graphs with iterative decoding algorithms. This project aims to apply
techniques from discrete mathematics to design new LDPC codes. The
outcomes of this research will be new LDPC codes, encoding algorithms
and analysis techniques for next-generation communications.
2002-2004 ARC Linkage Project Grant LP0211210, $269K
Chief Investigators: Dr. Brett Ninness and Dr. Steve Weller
Partner Investigators: Dr. Chris Nicol and Dr. Linda Davis
Industry Linkage Partner: Bell Labs (Lucent Technologies)
Meeting the global demand for mobile and wireless communications depends critically on reliable and high rate data transfer. Unfortunately, communications medium idiosyncrasies pose formidable challenges. Very recently, in combatting this, major breakthroughs have been achieved whereby the use of multiple antennas allows for drastic data-rate increases. These advances use sophisticated Space-Time coding methods, and while they are causing great excitement in terms of their simulation performance, it is not clear how they will perform in practice, or in fact how they are to be realistically implemented. This project will address this issue by building a testbed that implements a high rate wireless communications system using space-time and other coding methods.
Structural issues in control and state estimation for linear multivariable systems
1996-1998 ARC Large Research Grant A49601311, $165K
Chief Investigator: Dr. Steve Weller
Administering Institution: The University of Melbourne
The achievable performance of all control systems is
necessarily constrained by the dynamics of the system being
controlled. For multivariable (or multi-input, multi-output (MIMO))
systems, the nature of these constraints is considerably more complex
than for scalar (or single-input, single-output (SISO)) systems, and
present understanding is far from complete. The aim of this project is
to investigate the role of the underlying zero structure of
multivariable systems in delineating the achievable performance of
feedback control and state estimation schemes. The expected outcomes
of this project are control and estimation algorithms which exploit
the underlying structure, and which give quantitative results on the
achievable performance for both continuous-time and sampled-data model
formats.
Current postgraduate students
- Ray Brown
- John Dalton
- Alan Murray
- Ian Griffiths (with A/Prof. Brett Ninness)
- Geoff Knagge (with A/Prof. Brett Ninness)
Previous postgraduate students
- Sarah Johnson
- Daniel Hall (with Dr. Jamil Khan)
- Research overview talk at the Australian Communications Theory Workshop (AusCTW'05), 2-4 February 2005, Brisbane, Australia:
- Presentations for the Centre for Integrated Dynamics and Control (CIDAC) Kalman Filter short course, 8-9 November, 2001, Newcastle, Australia:
- Workshop presentation at 33rd IEEE Conference on Decision and Control (CDC'94) on Logic-based Switching Strategies for Self-adjusting Control, jointly presented with A.S. Morse (Yale University) and F.M. Pait (Universidade de Sao Paulo), 14-16 December, 1994, Lake Buena Vista, Florida:
- Structural issues in control design for linear multivariable systems, PhD thesis, December 1993.