Patent ID: 8908649

Claim:
A method for selecting a downlink primary carrier for transmitting data, comprising: configuring multiple downlink carriers for a terminal; configuring primary carrier selection information of the terminal, wherein the primary carrier selection information indicates that a downlink carrier corresponding to an uplink carrier of the terminal serves as a downlink primary carrier of the terminal, wherein the uplink carrier is an uplink primary carrier; and notifying the primary carrier selection information to the terminal so that the terminal sends ACKnowledgement (ACK)/Negative ACKnowledgement (NACK) messages in multiplexing mode corresponding to the multiple downlink carriers on the uplink primary carrier; wherein at least part of channel resources of the ACK/NACK messages corresponding to the multiple downlink carriers of the terminal on the uplink primary carrier are obtained according to a rule of mapping between at least one Physical Downlink Control Channel (PDCCH) on the downlink primary carrier and at least one ACK/NACK channel on the uplink primary carrier.