Patent 8737195 was granted and assigned to NEC Corporation on May, 2014 by the United States Patent and Trademark Office.
A base station outputs first detection information representing a code of a reference signal and representing a mobile device that is determined, on the basis of transition of a status at the time of occurrence of disconnection of the radio link between the mobile device and the base station, to be capable of causing the collision, and second detection information representing a code of a reference signal and representing a mobile device that is determined, on the basis of occurrence of failure of reconnection of the radio link between the mobile device and the base station, to be capable of causing the collision. A collision detection device estimates that, when the code and the mobile device of the first detection information coincide with the code and the mobile device of the second detection information, the collision of the reference signal will be caused.