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Nonlinear Signal Processing in Feedback Loops for Single Frequency Tracking

Speaker: Dr. Kandeepan Sithamparanathan, National ICT AustraliaAbstract: The problem of single-frequency carrier synchronisation is a well treated issue in the literature over the past several decades. Here, we revisit the problem, to enhance the performance of the synchronisation system, given the requirements, on an application specific basis. A typical example is, synchronising the beacon mode signal received from a LEO (Low Earth Orbital) satellite, transmitting at Ka-band (20Ghz/30Ghz) with heavy Doppler (+/- 600kHz) and very low transmitted EIRP (Effective Isotropically Radiated Power). Carrier synchronisation system requirements for such need to have wider acquisition range with a very low jitter-performance threshold in the order of -5dB of SNR. In order to address the above problems some nonlinear signal processing techniques are adopted to achieve wider acquisition ranges and extended jitter-threshold point in feedback loops. The loops are analysed both in its acquisition and tracking modes and signal processing solutions are proposed to enhance the performances. Another example of such application specific problem is to perform synchronisation for signals received with non-Gaussian additive noise such as impulsive noise. Linear analysis of feedback loops for the above two problems are no longer valid with the presence of the nonlinear elements within the loop, especially at very low signal to noise ratio levels. We use statistical analysis to study the dynamics of the loop and identify the limitations on it prior to addressing the problems on a specific manner to improve the performance.Bio: Kandeepan is with the Wireless Signal Processing group at the National ICT Australia in Canberra. He completed his undergraduate level of studies in Communications and Control systems engineering in Colombo, furthering with a masters in Telecommunications and a PhD in Electrical Engineering, in 1999 and 2003 respectively, at the University of Technology, Sydney (Australia). Prior to joining the National ICT Australia, he has worked with the Australian Cooperative Research Centre for Satellite Systems on the Fedsat project as a researcher and a DSP Engineer. Kandeepan was also involved with teaching and course development at the University of Technology, Sydney in the Telecommunications Engineering group and had developed technical materials for Nokia on 3G wireless systems. His main research interests are synchronisation, parameter estimation, statistical signal processing, and communication theory. Currently he is working on synchronisation techniques for Ultra Wide Band and MIMO based communication systems.Host: Dr. Urbashi Mitra, ubli@usc.edu

Location: Hughes Aircraft Electrical Engineering Center (EEB) - -539

Audiences: Everyone Is Invited

Contact: Mayumi Thrasher