Device and method for performing power allocation and out-band activation by using short-range communication in wireless power transmission system

A wireless power transmitter, comprising:

• a power converter including a plurality of primary coils and configured to transmit wireless power to a wireless power receiver by using at least one primary coil among the plurality of primary coils forming magnetic coupling with the wireless power receiver at an operating frequency;
• and
• a communicator/controller configured to communicate with the wireless power receiver by using the operating frequency based on in-band communication and communicate with the wireless power receiver by using a frequency different from the operating frequency based on out-band communication,
• wherein the wireless power transmitter is configured to:
• transmit, to the wireless power receiver, a message including at least one out-band identifier of at least one different wireless power receiver based on the out-band communication, and
• receive, from the wireless power receiver, information of a negotiation result based on the out-band communication, and
• wherein the information of the negotiation result includes a result of negotiation for power allocation between the wireless power receiver and the at least one different wireless power receiver.