Patent ID: 8036676

Claim:
A frequency sharing method for a second system using a frequency that a first system uses, comprising: receiving, by a receiving station of the first system, a signal from a transmitting station of the first system at a transmission frequency; transmitting, by the receiving station of the first system, a beacon signal indicating a reception range of the receiving station at the transmission frequency, the beacon signal including beacon information that includes at least one of modulation information, transmission-power information, and priority information related to the first system; detecting, by a transmitting station of the second system, the beacon signal transmitted from the receiving station of the first system; and judging, by the transmitting station of the second system, whether signal transmission from the transmitting station of the second system to a receiving station of the second system, which did not transmit the beacon signal, is possible at the transmission frequency used by the first system without interfering with the first system, based on the beacon information of the first system included in the beacon signal.