Systems and methods for switching radio resource allocation for User Equipment (UE) enabled for a device-to-device (D2D) communication. One embodiment is a base station that switches resource allocation between Mode 1, Mode 2, and a transition mode. For the transition mode, one or more parameters have a value in a range between a value specified in Mode 1 and a value specified in Mode 2 for the parameter(s). The base station detects movement of the UE from in-coverage of the base station to edge-of-coverage, and initiates switching of the resource allocation for the UE from Mode 1 to the transition mode. The base station then detects movement of the UE from edge-of-coverage of the base station to out-of-coverage, and initiates switching of the radio resource allocation for the UE from the transition mode to Mode 2.