On designing the optimal template waveform for UWB impulse radio in the presence of multipath

Using an appropriate template waveform matched to the received signal allows the energy of the received signal to be extracted efficiently. This efficiency becomes vital for ultra wide bandwidth (UWB) impulse radio in the presence of multipath, where each path undergoes a different channel, causing distortion in the received pulse shape due to a variety of factors, such as different amounts of attenuation for different frequencies (see Qui, R.C. and I-Tal Lu, IEEE Trans. on Vehicular Tech., vol.48, no.1, 1999; Qui, R.C., IEEE Vehicular Tech. Conf., 1998). In such a situation, using a clean ideal line of sight path signal as a template may degrade the performance due to the mismatches between the template waveform and the received signal. Furthermore, because of inherent filtering in the RF processing (i.e., antennas, amplifiers, etc.), it is often difficult to determine even such a clean line of sight pulse. Algorithms for designing optimal template waveforms for UWB impulse radio are developed and the improvement over a more traditional template waveform used for this kind of radio is illustrated.