A wireless power transmission apparatus including a controller configured to initiate a digital ping to solicit a response from a wireless power reception apparatus, perform a negotiation for a first available power indicator with the wireless power reception apparatus; and a power converter configured to transmit a wireless power to the wireless power reception apparatus according to the first available power indicator, wherein the controller is configured to transmit, to the wireless power reception apparatus in response to a received power packet, a bit pattern response requesting a communication by the wireless power transmission apparatus to change the first available power indicator, and transmit a packet related to a second available power indicator to the wireless power reception apparatus, and wherein the bit pattern response is defined as a pattern different from a bit pattern for an 8-bit ACK response, a bit pattern for an 8-bit NAK response and a bit pattern for an 8-bit ND response.