DEPARTMENT OF INFORMATION ENGINEERING

TRANSMISSION SYSTEMS RESEARCH GROUP: EXPERTISE

Via G. Caruso  56122 Pisa  Italy



The Transmission Systems Research Group has high-level expertise in various topics of communication theory, digital receiver design, and simulation of communication systems. In the last few years the group has been involved in the following research areas:

Synchronization methods
The group has developed a variety of synchronization algorithms suitable for traditional modulation schemes (PSK and QAM), multi-carrier transmissions, single-carrier and multi-carrier spread-spectrum systems. Current research projects include: (a) Timing and carrier frequency recovery for filtered multi-tone modulation and orthogonal frequency division multiple access; (b) Synchronization algorithms for carrier frequency/phase offset estimation with turbo-coded signals; (c) Frequency offset estimation for conventional and multi-carrier CDMA systems.

Channel estimation
Channel estimation amounts to measuring the channel impulse response or, alternately, the signal delays and attenuations along the propagation paths. If an antenna array is available at the receiver, the directions of arrival (DOAs) of the incoming rays can be used for ranging and localization purposes. Research projects are under way to estimate the propagation parameters (delays, attenuations, DOAs) in third generation CDMA systems.

Advanced digital modems
New receiver architectures are currently investigated for several applications, including high-speed modems for satellite turbo-coded communications, OFDM transmissions over fast-fading channels, and third generation DS-CDMA cellular systems. Suboptimal multiuser detectors and interference mitigation schemes are investigated that can cope with the near-far problem and still require reasonable computing resources.

Ultra-wideband communications
The Federal Communication Commission has recently permitted the operation of new communication systems incorporating ultra-wideband (UWB) technology. UWB devices operate with very short pulses (of about one nano-second) that result in extremely large transmission bandwidths. The group is currently investigating synchronization and detection issues related to UWB communications. As a typical UWB indoor channel exhibits hundreds of paths, it is crucial to efficiently select the most important ones so as to limit the receiver complexity while still capturing sufficient signal energy.


- Maintained by Filippo Giannetti: f.giannetti@iet.unipi.it - Last updated: July 23, 2004