A method and a first network node (800) serving a first cell (800A) in a wireless network, for enabling reduction of interference in a second cell (800B) caused by transmission of reference signals in the first cell (800A). The first network node (800) transmits (8:1) scheduling blocks with said reference signals, using a time offset relative transmission of scheduling blocks in the second cell. A timing advance value is determined (8:3) for a wireless device (802) and the wireless device (802) instructed (8:4) to apply said timing advance value for uplink transmissions. The timing advance value was determined such that uplink symbols transmitted from the wireless device (802) are aligned with uplink symbols received at a second network node (804) of the second cell (804A).