UWB radio deployment challenges

The challenges related to the deployment of ultrawideband (UWB) radios are posed in terms of interference issues that UWB radio systems will encounter. The problem of coexistence with a Global Positioning System (GPS) receiver is used as an experimental example. Calculation of an upper bound to UWB transmitter power illustrates the effect of one possible type of regulation for a given UWB antenna system. The inteference environment for a UWB receiver is used to lower bound the UWB transmitter power necessary for a given data rate. Sample measurements are provided. INTRODUCTION Ultrawideband radios often are deÞned to have the property that their 3 dB bandwidth is at least 25% of the center frequency of the radiation. This characteristic means that such radios normally must coexist with many other narrowband signals that occupy their extremely large transmission bandwidth, with none of these systems suffering intolerable interference problems. The rationale for deploying UWB radio systems lies in the beneÞts of exceptionally wide bandwidths at the lowest possible frequencies for those bandwidths: (1) very Þne time resolution for accurate ranging, imaging, and multipath fading mitigation, and (2) the material penetration capability of relatively low frequencies. Tolerance of interference to/from coexisting systems comes at a price. The primary objective of this paper is to lay out this problem and give measured examples of the signal environments which may be encountered.