The present disclosure relates to a wireless power transmitter for performing communication with a wireless power receiver using a plurality of slots, and the wireless power transmitter may include a power conversion unit configured to transmit a wireless power signal to the wireless power receiver, and a power transmission control unit configured to perform communication with the wireless power receiver using the wireless power signal, wherein the power transmission control unit performs steps including receiving control information from the wireless power receiver within any one of the plurality of slots, transmitting an ACK signal to the wireless power receiver in response to the control information, and allocating the any one slot to the wireless power receiver to perform communication with the wireless power receiver using the any one slot when the ACK signal is received.