Embodiments herein relate to a method in a radio network node (1) for enabling a user equipment (10) to access a radio communications network. The user equipment (10) is located in an area of the radio communications network. The radio network node (1) retrieves a system signature. The system signature is indicating a set of system information to be used by the user equipment (10) to access the radio network node (1). The radio network node (1) then transmits the system signature within the area. This enables the user equipment (10) to access the radio communications network.