RAKE reception for IR-UWB systems in high mobile environments

A new method of RAKE reception for Impulse Radio Ultra Wideband (IR-UWB) systems in high mobile environments is described. The conventional multipath diversity reception method for UWB is RAKE receiver, which is usually applied under static environments. In high mobile environments, due to extremely wide bandwidth of UWB signals, frequency components are shifted differently and this makes the pulse-width change in the time domain. Aiming at block-transmission UWB systems, pilot symbols are inserted to estimate the scale change factor. Template signal for RAKE receiver is resampled to compensate the Doppler effect. Simulation results demonstrate that this method could eliminate the Doppler effect and improve the bit error rate (BER) performance. Simulation results also show that the BER performance is not only related to relative velocity, but also related to block length and pilot symbol period. When pilot symbol period increases, the performance degrades. So in the practise block structure should be well designed according to the mobile environments.