In a non-limiting and exemplary embodiment, a method is provided for sharing secondary cognitive radio resource user related information. A coexistence node receives information on network properties associated with secondary cognitive radio resource users. An upload message is generated and sent, the upload message comprising for a secondary user database at least information on the received network properties associated with secondary cognitive radio resource users. A location-dependent network map comprising at least information on network properties is generated. The network map is sent to assist one or more secondary cognitive radio resource users.