A method by a base station for receiving power headroom reporting from a user equipment (UE) in a Multi-Radio Access Technology (RAT)-Dual Connectivity (MR-DC) scenario, the method includes receiving a DC Power Headroom Report (PHR) Medium Access Control (MAC) Control Element (CE) from the UE, the DC PHR MAC CE having a fixed number of octets with cell index fields for indicating whether a power headroom (PH) for a serving cell with a corresponding cell index is reported, wherein the fixed number of octets is independent of a highest secondary Cell Index (SCellIndex) for serving cells with configured uplinks.