Methods and apparatuses are disclosed for small cell enhancement in a wireless communication system. The method includes a user equipment (UE) served by a first cell, wherein the first cell is controlled by a first evolved Node B (eNB). The method further includes receiving, by a UE, a Radio Resource Control (RRC) message for adding a second cell controlled by a second eNB to the UE. The method also includes transmitting, by the UE, a first power headroom report (PHR) to the first eNB and a second PHR to the second eNB in which both the first PHR and the second PHR contain power headroom values of both the first cell and the second cell.