With the great expansion of wireless communications, jamming becomes a real threat. We propose a new model to evaluate the robustness of a communication system to jamming. The model results in more scenarios to be considered ranging from the favorable case to the worst case. The model is applied to a TH-UWB radio. The performance of such a radio in presence of the different jamming scenarios is analyzed. We introduce a mitigation solution based on stream cipher that restricts the jamming problem of the TH-UWB communication to the more favorable case while preserving confidentiality.