A method performed by a WTRU may comprise receiving PRS configuration information and performing a first set of measurements based on the PRS configuration. The method may further comprise determining whether to trigger an on-demand PRS request based on the first set of measurements and on-demand PRS criteria. On a condition that the determining to trigger is affirmative, transmitting an on-demand PRS request. In embodiments, the on-demand PRS criteria may be based on an RSRP, TDoA, number of multipaths, accuracy and/or latency.