In an ultra-wideband (UWB) communication network, a controller anchor changes which anchor of a group of anchors serves as initiator for each of multiple ranging rounds. Based on the capabilities of the anchors in the UWB communication network, the controller selects among multiple modes for designating which anchor serves as initiator for each ranging round. In a first mode, the anchors take turns serving as the initiator for successive ranging rounds in round robin fashion. In a second mode, the anchors randomly take turns serving as the initiator for ranging rounds. By dynamically selecting an initiator for each ranging round, launching a successful jamming attack becomes significantly more complicated.