A method for wireless power transmission, comprising: receiving a first foreign object detection status packet and a second foreign object detection status packet from a wireless power receiver (20, 700); transmitting a foreign object detection indicator indicating that a foreign object is present in a charging area to the wireless power receiver (20, 700) when the foreign object is present in the charging area based on the first foreign object detection status packet or the foreign object is present in the charging area based on the second foreign object detection status packet; proceeding to a first subsequent phase of a charging procedure when the foreign object is not present in the charging area based on the first foreign object detection status packet and the foreign object is not present in the charging area based on the second foreign object detection status packet; or proceeding to a second subsequent phase of the charging procedure requesting an end of the charging procedure or proceeding to a third subsequent phase of the charging procedure different than the end of the charging procedure when the foreign object is present in the charging area based on the first foreign object detection status packet or the foreign object is present in the charging area based on the second foreign object detection status packet, characterized in that: the first foreign object status packet includes a reference quality factor, and the second foreign object status packet includes a reference peak frequency, wherein the foreign object detection indicator is determined using a measured quality factor of a power signal transmitted from the wireless power transmitter (10, 600) and the reference quality factor of the first foreign object detection status packet, or determined using a measured peak frequency of the power signal transmitted from the wireless power transmitter (10, 600) and the reference peak frequency of the second foreign object detection status packet. receiving a first foreign object detection status packet and a second foreign object detection status packet from a wireless power receiver (20, 700); transmitting a foreign object detection indicator indicating that a foreign object is present in a charging area to the wireless power receiver (20, 700) when the foreign object is present in the charging area based on the first foreign object detection status packet or the foreign object is present in the charging area based on the second foreign object detection status packet; proceeding to a first subsequent phase of a charging procedure when the foreign object is not present in the charging area based on the first foreign object detection status packet and the foreign object is not present in the charging area based on the second foreign object detection status packet; or proceeding to a second subsequent phase of the charging procedure requesting an end of the charging procedure or proceeding to a third subsequent phase of the charging procedure different than the end of the charging procedure when the foreign object is present in the charging area based on the first foreign object detection status packet or the foreign object is present in the charging area based on the second foreign object detection status packet, characterized in that: the first foreign object status packet includes a reference quality factor, and the second foreign object status packet includes a reference peak frequency, wherein the foreign object detection indicator is determined using a measured quality factor of a power signal transmitted from the wireless power transmitter (10, 600) and the reference quality factor of the first foreign object detection status packet, or determined using a measured peak frequency of the power signal transmitted from the wireless power transmitter (10, 600) and the reference peak frequency of the second foreign object detection status packet. the first foreign object status packet includes a reference quality factor, and the second foreign object status packet includes a reference peak frequency, wherein the foreign object detection indicator is determined using a measured quality factor of a power signal transmitted from the wireless power transmitter (10, 600) and the reference quality factor of the first foreign object detection status packet, or determined using a measured peak frequency of the power signal transmitted from the wireless power transmitter (10, 600) and the reference peak frequency of the second foreign object detection status packet.