A method for receiving a wireless power from a wireless power transmitter , the method performed by a wireless power receiver and comprising: transmitting, to the wireless power transmitter , a configuration packet comprising first information which is composed of 1 bit, wherein the first information related to the wireless power receiver informs whether simultaneous incoming and outgoing data stream are supported or not supported; receiving, from the wireless power transmitter , a capability packet comprising second information which is composed of 1 bit, wherein the second information related to the wireless power transmitter informs whether simultaneous incoming and outgoing data stream are supported or not supported; transmitting, to the wireless power transmitter , a first data stream that includes: (i) an initial auxiliary data control, ADC, data packet opening the first data stream, (ii) a sequence of auxiliary data transport, ADT, data packets including a first actual message, and (iii) a final ADC data packet closing the first data stream; and receiving, from the wireless power transmitter , a second data stream that includes: (i) an initial ADC data packet opening the second data stream, (ii) a sequence of ADT data packets including a second actual message, and (iii) a final ADC data packet closing the second data stream, wherein the wireless power receiver transmits the first data stream and simultaneously receives the second data stream, based on the first information and the second information informing simultaneous support. transmitting, to the wireless power transmitter , a configuration packet comprising first information which is composed of 1 bit, wherein the first information related to the wireless power receiver informs whether simultaneous incoming and outgoing data stream are supported or not supported; receiving, from the wireless power transmitter , a capability packet comprising second information which is composed of 1 bit, wherein the second information related to the wireless power transmitter informs whether simultaneous incoming and outgoing data stream are supported or not supported; transmitting, to the wireless power transmitter , a first data stream that includes: (i) an initial auxiliary data control, ADC, data packet opening the first data stream, (ii) a sequence of auxiliary data transport, ADT, data packets including a first actual message, and (iii) a final ADC data packet closing the first data stream; and (i) an initial auxiliary data control, ADC, data packet opening the first data stream, (ii) a sequence of auxiliary data transport, ADT, data packets including a first actual message, and (iii) a final ADC data packet closing the first data stream; and receiving, from the wireless power transmitter , a second data stream that includes: (i) an initial ADC data packet opening the second data stream, (ii) a sequence of ADT data packets including a second actual message, and (iii) a final ADC data packet closing the second data stream, (i) an initial ADC data packet opening the second data stream, (ii) a sequence of ADT data packets including a second actual message, and (iii) a final ADC data packet closing the second data stream, wherein the wireless power receiver transmits the first data stream and simultaneously receives the second data stream, based on the first information and the second information informing simultaneous support. <EOS>