Receiver Designs for Ultra-Wide Bandwidth Communications

Ultra-wide bandwidth (UWB) communication is a promising candidate for high speed, low power and short range indoor wireless communications and is a technique for spectrum sharing. However, the pulse based UWB technique has been overlooked by the industry due to some implementation issues from its narrow pulse shape and the transmission power limitations put by regulating bodies. This project designs and investigates simple and efficient receiver structures/techniques that have the potential of improving the performance or reducing the receiver complexity to make impulse based UWB techniques more attractive for commercial applications.;The multiuser interference in UWB systems is non-Gaussian distributed. The use of statistical methods for improved multiuser detection for UWB communication is investigated.;An adaptive nonlinear receiver is derived based on a Gaussian-Laplacian mixture model for the ambient noise plus multiple access interference. A simplified version of this receiver is also derived. Receiver parameter estimation techniques are proposed and the receiver performances are studied.;The flexibility of the alpha-stable model for modeling the multiple access interference in varying channel conditions is investigated. Adaptive receiver structures based on a myriad filter are proposed for improved signal detection. This nonlinear signal processing yields a significant level of improvement in the bit error rate. A method to estimate the receiver parameters in actual implementation is proposed. Also, the optimal linear combiner for signal detection in symmetric alpha stable noise is derived.;Transmitted reference UWB systems have been proposed in the literature to simplify UWB receivers. In the first part, this project investigates the performance of transmitted reference UWB systems and develops a generalized method to analyze their performance. In addition, the integrated cross-noise term appearing in correlation receivers and its statistics are also studied.;Another adaptive receiver is also proposed based on using the optimal linear combiner for demodulation and the myriad filter nonlinear detector for detection. Then performances of the proposed receivers are studied in realistic UWB channels with a two dimensional Poisson user spatial distribution model. The effect of the channel characteristics on the the receiver structure is also discussed.