A method for a User Equipment, UE, operating in a wireless communication system, the method comprising: configuring a first Medium Access Control, MAC, entity corresponding to a first eNodeB, and a second MAC entity corresponding to a second eNodeB; triggering power headroom reporting, PHR, in the first MAC entity and the second MAC entity in response to a first type event occurring in the first MAC entity; and triggering PHR in the first MAC entity only, in response to a second type event occurring in the first MAC entity, characterized in that wherein the first type event comprises: a prohibitPHR-Timer of the first MAC entity has expired when the UE has uplink resources for a new transmission to the first eNodeB, and following conditions are in true in a corresponding Transmission Time Interval, TTI, for a cell of any of activated serving cells belonging to the first MAC entity with configured uplink, wherein the conditions comprise: there are uplink resources allocated for transmission or there is a Physical Uplink Control Channel, PUCCH, transmission on the cell, and a required power backoff due to power management for the cell has changed more than a threshold since a last transmission of a PHR to the first eNodeB when the UE had the uplink resources allocated for the transmission, or the first PUCCH transmission on the cell. configuring a first Medium Access Control, MAC, entity corresponding to a first eNodeB, and a second MAC entity corresponding to a second eNodeB; triggering power headroom reporting, PHR, in the first MAC entity and the second MAC entity in response to a first type event occurring in the first MAC entity; and triggering PHR in the first MAC entity only, in response to a second type event occurring in the first MAC entity, characterized in that wherein the first type event comprises: a prohibitPHR-Timer of the first MAC entity has expired when the UE has uplink resources for a new transmission to the first eNodeB, and following conditions are in true in a corresponding Transmission Time Interval, TTI, for a cell of any of activated serving cells belonging to the first MAC entity with configured uplink, wherein the conditions comprise: there are uplink resources allocated for transmission or there is a Physical Uplink Control Channel, PUCCH, transmission on the cell, and a required power backoff due to power management for the cell has changed more than a threshold since a last transmission of a PHR to the first eNodeB when the UE had the uplink resources allocated for the transmission, or the first PUCCH transmission on the cell. a prohibitPHR-Timer of the first MAC entity has expired when the UE has uplink resources for a new transmission to the first eNodeB, and following conditions are in true in a corresponding Transmission Time Interval, TTI, for a cell of any of activated serving cells belonging to the first MAC entity with configured uplink, wherein the conditions comprise: there are uplink resources allocated for transmission or there is a Physical Uplink Control Channel, PUCCH, transmission on the cell, and a required power backoff due to power management for the cell has changed more than a threshold since a last transmission of a PHR to the first eNodeB when the UE had the uplink resources allocated for the transmission, or the first PUCCH transmission on the cell. there are uplink resources allocated for transmission or there is a Physical Uplink Control Channel, PUCCH, transmission on the cell, and a required power backoff due to power management for the cell has changed more than a threshold since a last transmission of a PHR to the first eNodeB when the UE had the uplink resources allocated for the transmission, or the first PUCCH transmission on the cell.