Abstract: An acquiring unit receives a packet signal of a first type from the other base station apparatus. A measuring unit measures a receipt frequency of the packet signal of the first type which is received. A determining unit determines a timing for broadcasting a packet signal of a second type to inform a terminal apparatus of a presence based on the receipt frequency which is measured and a receipt timing of the packet signal of the first type which is received. A broadcasting unit broadcasts the packet signal of the second type in the determined timing. A communicating unit executes a communication with the terminal apparatus receiving the packet signal of the second type.

Abstract: A positional information acquiring unit acquires positional information of a vehicle. An intersection predicting unit predicts an intersection, which the vehicle will enter, by associating the positional information with map information. An entrance predicting unit acquires the positional information of another vehicle included in a packet signal from a transmitting apparatus mounted on the other vehicle and associates the positional information of the other vehicle with the map information, thereby predicting whether the other vehicle enters the intersection predicted by the intersection predicting unit. When entrance of the other vehicle is predicted, an effect predicting unit predicts whether travel of the other vehicle has an effect on this vehicle based on traveling direction information of the other vehicle acquired from the packet signal. The notifying unit notifies presence of the other vehicle when presence of the effect is predicted.