Communications Signal Processing Group

Wireless data communications is becoming ubiquitous. To meet the demands of future high-speed wireless applications, systems are approaching fundamental physical limits, where implementation complexity is a major problem. Iterative information processing has emerged as the dominant low-complexity design paradigm.

The aim of this project is the optimization of data communications systems subject to constraints on computational complexity. The project builds on previous research accomplishments in these areas, aiming to formally include complexity constraints into the design of concatenated coding systems, and into the development of low-complexity iterative algorithms. The main research tasks are to formulate a mathematically tractable measure of complexity relevant for concatenated systems and corresponding iterative processing algorithms, and to incorporate this analytical complexity measure into the design of optimal, complexity-constrained code structures.

With higher data rates in wireless communication networks, new broadband services like DVD-quality video and CD-quality audio become relevant for wireless devices. Each application requires the network to deliver a specific Quality-of-Service (QoS) in terms of minimum errors and delay. Performance of broadband wireless communication networks is limited by availability of resources such as frequency bandwidth and transmission power.

A major network design challenge is to provide a wide range of QoS, given the limitations of wireless channels, and the limited available resources. Transmission schemes, adapting to instantaneous channel characteristics can significantly improve performance.

The main objective of this project is to increase the throughput of future wireless communications systems by adopting adaptive principles in the underlying communications protocols. The specific aims are to determine optimal adaptive transmission strategies for delay-limited block-fading channels, minimizing the outage probability; extract design guidelines for adaptive transmission schemes through a thorough theoretical understanding of the outage probability; and develop practical adaptive, low-complexity coding and decoding strategies that can perform arbitrarily close to the outage probability for delay-limited block-fading channels.

Advances in the development of special-purpose wireless ad hoc networks will provide opportunities for emerging wireless applications. Example applications with significant relevance to Australia include public safety and emergency-area communications. Cooperative communications is a new technology specifically targeting performance improvements in wireless ad hoc networks.

The aim of the project is the design, evaluation and implementation of efficient transmission strategies for reliable communication across cooperative wireless ad hoc networks. The project focuses on the innovative use of channel and network coding techniques to increase reliability, throughput, and coverage of cooperative wireless ad hoc networks.

The main task is to devise new transmission strategies for application across all nodes within a cooperative wireless network of arbitrary size and topology. The emphasis will be on efficiency, simplicity, and scalability to allow for practical implementation. Two key concepts are to employ multi-layer transmission schemes for cooperation and to exploit inherent properties of wireless channels for network coding.