Energy capture vs. correlator resources in ultra-wide bandwidth indoor wireless communications channels

The results of an ultra-wide bandwidth (UWB) signal propagation experiment performed in a typical modern office building are presented. The bandwidth of the signal used in this experiment is in excess of one GHz, which results in a multipath resolution of less than a nanosecond. The maximum likelihood (ML) detector, based on a specular multipath channel model, is derived to detect multipath components of the measured waveforms. The results show that typical received waveforms consist of a finite number of dominant multipath components. The number of dominant multipath components is equivalent to the number of single-path signal correlators required in a UWB RAKE receiver. The number of single-path signal correlators required to construct a filter matched to the received waveform, so that the constructed waveform adequately captures the average received signal energy, is a useful parameter for UWB RAKE receiver design. The quantity, energy capture, is defined mathematically for use as a performance measure of the ML detector. The energy capture as a function of the number of single-path signal correlators is evaluated for each of the experimentally measured received waveforms, and typical results are presented.