Determining an association between DMRS and PTRS

A method in a user equipment (UE), the method comprising:

• determining a plurality of physical resource blocks having phase tracking reference signals;
• receiving downlink control information (DCI) comprising resource allocation information that indicates a mapping between each physical resource block of the plurality of physical resource blocks and a corresponding demodulation reference signal port index of a plurality of demodulation reference signal port indexes;
• determining the mapping between each physical resource block of the plurality of physical resource blocks and the corresponding demodulation reference signal port index of the plurality of demodulation reference signal port indexes based on the DCI;
• determining a scheduled physical resource block position and bandwidth for a physical resource block of the plurality of physical resource blocks based on the DCI;
• and
• determining, based on the scheduled physical resource block position and bandwidth and the mapping, an associated demodulation reference signal port index of the plurality of demodulation reference signal port indexes within the physical resource block for a phase tracking reference signal.