Patent ID: 7852821

Claim:
A signaling method which is performed by a cognitive radio (CR) base station in a CR environment, the method comprising: broadcasting an Explicit Outband Signal (EOS) via one or more outband channels, according to a predetermined period; receiving a sensing report signal with respect to a system which utilizes at least one of the one or more outband channels, from a CR terminal which makes a communication via the one or more outband channels; and in response to receiving the sensing report, determining whether the sensed system is an incumbent system; in response to determining the sensed system is an incumbent system, stopping transmission of an EOS on the at least one outband channel, finding an available outband channel, and switching the at least one outband channel of the CR terminal to the available outband channel; and in response to determining the sensed system is not an incumbent system, continuing to transmit the EOS on the at least one outband signal, searching for an available outband channel, and, if there is an available outband channel, switching the at least one outband channel of the CR terminal to the available outband channel.