Pulse shaping in UWB communication systems

Pulse shapes previously proposed for ultrawideband communication systems are studied and compared to determine which provide the best performance. The performance measures considered are the bit error rate in multiple access interference environments and compliance with required spectral emission constraints. The Gaussian monocycles of higher-order and the prolate spheroidal function based pulses are found to meet the spectral emission masks without frequency shifting. Frequency shifting and bandpass filtering must be used for the modified Hermite polynomial based pulses to meet the spectral masks. The multiaccess performance average error rates of time-hopping ultra-wideband systems using the different pulse shapes are examined and compared using an exact performance analysis method newly published. The Gaussian monocycles are shown to achieve performance as good as the prolate spheroidal function based pulses with the same effective bandwidths in numerical examples. The Gaussian monocycles outperform the modified Hermite polynomial based pulses for the system models considered. Some tradeoffs of these pulses are also addressed in terms of the complexity of their implementations and the average bit error probabilities.