The indoor propagation channel appears differently to ultra-wideband (UWB) wireless systems than it does to narrowband (NB) sine wave systems. UWB impulses are short and generally don't overlap like multipath sine waves. This paper presents the results of measurements made on the UWB indoor propagation channel. The channel impulse response (CIR) of the indoor office channel is extracted from the measurements using a variant of the CLEAN algorithm. The UWB propagation channel statistics are calculated from the CIRs. Major results of the analysis are as follows: i) The pathloss versus distance obeys a power law (1/d(N)) curve fit with the peak received power falling off with N=2.9 and the total received power falling off with N=2.1. This suggests that receiver architectures that can take advantage of the total received power can overcome much of the pathloss of the indoor channel. ii) The potential of a 4 element RAKE receiver is explored showing this benefit as the peak power plus RAKE gain falls off with N=2.5, somewhat offsetting the excess pathloss of the channel. iii) The lognormally distributed standard deviation of the mean pathloss versus distance was found to be 4.75 dB, 4.04 dB, and 3.55 dB for the peak, peak plus RAKE, and total power pathloss, respectively. This suggests that a relatively small fading margin is required for UWB systems (compared to NB systems). iv) The rms delay spread of the indoor channel increases with increasing T-R separation and also with increasing path loss. Results presented in this paper can aid in the design of UWB systems to overcome the challenges posed by the indoor channel.
