According to a first aspect of embodiments herein, the object is achieved by a method in a method in a network node for handling beacon signal transmission. The beacon signal transmission is for discovering devices for Device to Device, D2D, transmission. The network node is associated with a cellular communications network. The network node obtains (1401) information from a number of master devices within a specific area comprised in the cellular communications network. The respective information comprises information about location and capability of D2D transmission of the respective master devices. The network node then decides (1403) properties for beacon signal transmission from a first master device. The deciding is based on the obtained information, and the number of master devices within the specific area.