Performance considerations of wireless multiple -access digital impulse radio under realistic multipath channels.

摘要

Ultra Wide Bandwidth (UWB) radio has recently been considered as a candidate for short range, high data rate wireless multiple-access communication systems. UWB radio promises a great multiple-access capacity under ideal propagation conditions. In this thesis, performance of wireless multiple access digital impulse radio under realistic multipath channels is investigated. Both time-hopping and direct-sequence spreading schemes along with pulse position and antipodal data modulations are analyzed.;The optimal template waveform design for use at the receiver correlator in order to capture the most amount of energy out of the multipath received signal with the least number of correlations is studied. Since this template waveform algorithm processes only the received signal, channel characteristics and the effects of the antennas on the received pulse shape are implicitly embedded in the design of the optimal template, which are difficult to account for with mathematical models.;UWB radio performance in the presence of an arbitrary external interference source is evaluated and narrow band interference rejection using doublet pulses is described. Power spectral density of multiple access digital impulse radio for both time-hopping pulse position modulation and direct-sequence bit flipping modulation in the presence of multipath is derived. UWB radio under new spectral masks imposed by regulatory authorities is discussed followed by future research directions of interest.