Time hopping impulse radio commonly encodes data symbols by shifting the position of transmitted pulses over a time gap that is quantized within the inter pulse interval range. In this paper, we adopt a previously investigated coding scheme that considers real-valued codes, and as such introduces time hopping in a "fluid" way. We analyze the application of fluid time hopping to UWB sensor networks. For this purpose we consider a fluid time hopping implementation that is simplified to the maximum extent, in order for it to be appropriate for those networks that need a flexible and easily adjustable multiple access scheme. Fluid time hopping proves in fact to allow fast, detailed, and low-complexity spectrum management, as most suitable in self-organizing networks