A system, method, and device for ensuring a number of Phase Tracking Reference Signal(s) (PT-RSs) are the same for multiple slots. A wireless transmit/receive unit (WTRU) may receive control information including a number of scheduled resource blocks (RBs) then determine a PT-RS density based on the number of scheduled RBs. The WTRU may determine a RB offset value for the WTRU based on a WTRU-ID modulo the maximum RB offset value, where the maximum value for the RB offset value may be based on at least one of the number of the scheduled RBs and the PT-RS density. The WTRU may then transmit or receive a signal with PT-RS based on the RB offset value.