A method for a UE in a multiple transmission points communication system, mTRP, scheme, is provided. The method includes receiving downlink control information, DCI, indicating at least two transmission points scheme for a scheduled data transmission on physical resource blocks, PRBs. The PRBs includes at least a first subsets of PRBs, associated with a first transmission point, and a second subset of PRBs, associated with a second transmission point. The method further includes determining a first PT-RS frequency density for the first set of PRBs based on the number of PRBs in the first set of PRBs and a second PT-RS frequency density based on the number of PRBs in the second set of PRBs. A UE, methods for a base station and a base station are also provided.