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“Energy Capture vs. Correlator Resources in Ultra-Wide Bandwidth Indoor Wireless Communications Channels”
by Moe Z. Win and Robert A. Scholtz
November 1997
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 the excess of one GHz, which results in the 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 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 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. 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.