Patent ID: 8031643

Claim:
A method for multiplexing and transmitting an ACKnowledgment/Negative ACKnowledgment (ACK/NACK) as a result of use of a Hybrid Automatic Repeat reQuest (HARQ) scheme by a Node B in an Orthogonal Frequency Division Multiple Access (OFDMA) system, the method comprising the steps of: scheduling User Equipments (UEs); grouping the scheduled UEs so that UEs having ACK/NACK transmitting power within a predetermined range belong to one group, and setting up scheduling channels for each UE group; transmitting scheduling channel signals to the UEs via scheduling channels set up for each UE group; and transmitting ACK/NACKs to respective UEs of a UE group, the ACK/NACKs being transmitted to the UE group, in a frequency band for the UE group among frequency bands differently allocated to respective UE groups, in accordance with a CDM (Code Division Multiplex) scheme, wherein a code index of an ACK/NACK transmitted in the frequency band is set up to be identical to an index of the scheduling channels set up for UEs belonging to the one UE group.