Pulse shape design for ultra wide band communications

Ultra Wideband (UWB) technology is promising for high-speed short-range communication applications due to its large bandwidth, high data rate, low power requirement and short-range characteristics. Instead of exploring new unused frequency band, the UWB communication follows the overlay principle. The great potential of UWB lies in the fact that it can co-exist with the already licensed spectrum users and can still pave the way for a wide range of applications. Pulse shape design is a key technique in the UWB system. This thesis concentrates on pulse shaping techniques for UWB communication system. -- This thesis first summarizes the main pulse shaping schemes, and then describes the design of a pulse shaping method based on combining Gaussian derivative pulses for impulse based UWB systems. New pulse shapes are created to satisfy the Federal Communications Commission (FCC) spectral mask by this method. Since the objective function of the received signal-to-noise ratio (SNR) optimization is affected by different factors, multiple parameters are also designed to try to achieve the best received SNR. The performance of new pulses and other frequently used UWB pulses are compared through theoretical calculations and simulations coded in MATLAB. -- The main contributions of this thesis include the new determined way of combining certain numbers of Gaussian derivative pulses to create a single pulse that not only conforms to the FCC spectral mask, but also effectively exploits the permitted frequency spectrum, as well as the development of an end-to-end UWB signal transmission simulation chain that can use Time Hopping Pulse Position Modulation (TH-PPM) modulation and Time Hopping Binary Phase Shift Keying (TH-BPSK) modulation through an Additive White Gaussian Noise (AWGN) channel and the IEEE 802.15.3a standard channel model. -- Comparisons have been done of the overall performance of the systems using different pulses in various scenarios such as: single link system use AWGN channel and IEEE standard channel and multiuser system using AWGN channel and IEEE standard channel. In order to exploit the temporal diversity of the multi-path IEEE channel to improve performance of the decision process, a perfect RAKE receiver simulation model is used in the simulation chain. The theoretical calculation and simulation results indicate that the proposed pulses outperform other pulses to different extents under different situations. Discussions on the implementation issues of the pulse shaper are also provided in this thesis. -- The work reported here could act as a starting point from which improvements and extensions can be made and incorporated