Performance Comparison of Pulse Shapes in STDL and IEEE 802.15.3a models of the UWB Channel

Abstract

This paper demonstrates performance comparison of ultra wideband (UWB) systems in the stochastic tapped delay line (STDL) and IEEE 802.15.3a models of the UWB channel with RAKE receiver in presence of multiple user interference (MUI). System models are based on direct sequence code division multiple access (DS-CDMA) principle with bi-phase modulation (BPM). The system has been studied in presence of multiple user interference (MUI) and Gaussian noise. During the analysis, various types of narrow, sub-nanosecond pulses with same power were used and extensive simulations were run. The simulation results show that pulse shape has noticeable impact on the BER performance with the STDL channel model. The performance of the pulse waveform based on third derivative of Gaussian pulse has proved to be better than other pulses that were used with STDL channel model. On the other hand, maintaining the same parameters but by using IEEE 802.15.3a channel model shows that pulse shapes have no effect on BER performance. Spectral behavior of higher order Gaussian pulses has been explained. Finally, it is concluded that for STDL model, the third derivative of Gaussian pulse is the most suitable pulse shape for fulfilling the FCC regulated power spectral density (PSD) requirement and BER performance in multi-user interference environment, whereas using IEEE 802.15.3a channel, at least 4th or 5th derivative of Gaussian pulse should be chosen since increasing derivative order increases the peak emission frequency but decreases signal bandwidth