Abstract: A method performed by a Network Node (NN) for handling Device to Device (D2D) operation between a first D2D User Equipment (UE) and a second D2D UE in a radio communications network is provided. The NN obtains data related to propagation delay in one or more cells served by the NN. The propagation delay is related to any one or more out of: the first D2D UE, the second D2D UE, other D2D UEs, and cellular UEs. The NN then determines whether or not to configure a number of Guard Period (GP) symbols within a switching time resource, as Sidelink (SL) radio resources for the D2D operation. The determining is based on one or more criteria applied to the obtained data related to the propagation delay.