Abstract-A comprehensive statistical model is described for ultrawideband (UWB) propagation channels that is valid for a frequency range from 3-10 GHz. It is based on measurements and simulations in the following environments: residential indoor, office indoor, builtup outdoor, industrial indoor, farm environments, and body area networks. The model is independent of the used antennas. It includes the frequency dependence of the path gain as well as several generalizations of the Saleh-Valenzuela model, like mixed Poisson times of arrival and delay-dependent cluster decay constants. A separate model is specified for the frequency range below 1 GHz. The model can thus be used for realistic performance assessment of UWB systems. It was accepted by the IEEE 802.15.4a Task Group as standard model for evaluation of UWB system proposals. This paper also presents a critical assessment of the applicability of the model and possible generalizations and improvements.

Abstract-This paper describes a comprehensive statistical model for UWB propagation channels that is valid for a frequency range from 3-10 GHz. It is based on measurements and simulations in the following environments: residential indoor, office indoor, built-up outdoor, industrial indoor, farm environments, and body area networks. The model is independent of the used antennas. [7] developed the concept of time-hopping impulse radio (TH-IR) systems. In 2002, the frequency regulator in the USA allowed unlicensed UWB transmission (subject to the fulfillment of a spectral masks), and other countries are expected to follow suit. One of the most promising applications for UWB are sensor networks, where the good ranging and geolocation capabilities of UWB [8] are particularly useful. The data rates for those applications are typically low (<1 Mbit/s). Recognizing these developments the IEEE has established the standardization group 802.15.4a, which is currently in the process of developing a standard for these applications.The ultimate performance limits of any communications system are determined by the channel it operates in. For a UWB system, this is the UWB propagation channel, which differs from conventional (narrowband) propagation in many respects. The performance of a system thus can only be evaluated when realistic channel models are available. A number of UWB channel models have been proposed in the past: [9] suggested a model for the frequency range below 1 GHz (this model was adopted by the 802.15.4a group for testing of low-frequency UWB systems). The IEEE 802.15.3a group developed a channel model [10] that is valid from 3 − 10 GHz, but is designed only for indoor residential and office environments, and the distance between transmitter and receiver is restricted to < 10 m.

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