A method performed by a network node 110, for improving the performance of a handover of a user equipment (UE) 120, wherein the network node 110 serves a first cell 130 comprising one or more UEs 120. When the network node 110 has detected that a Signaling Radio Bearer (SRB) is determined to be scheduled for a UE 120 in handover from the first cell 130 to a second cell 131, the network node 110 increases the Control Channel Element (CCE) aggregation level in an OFDM-subframe to be sent to the UE 120 in a TTI related to the handover. By increasing the CCE aggregation level during a handover procedure, the effective coding rate of the PDCCH is increased, which leads to a more robust coding and reliability. Thereby the number of unsuccessful handovers and lost service is effectively reduced.