Patent ID: 8295155

Claim:
A method for transmitting ACKnowledgment/Negative ACKnowledgment (ACK/NACK) information at a User Equipment (UE) in a wireless communication system, the method comprising: receiving data from a Base Station (BS); acquiring a cyclic shift value and an orthogonal cover Walsh code that are mapped to an ACK/NACK channel index for the UE based on a mapping relationship between ACK/NACK channel indexes and cyclic shift values and orthogonal cover Walsh codes; and transmitting ACK/NACK information for the received data using the acquired cyclic shift value and the orthogonal cover Walsh codes, wherein according to the mapping relationship, first and third orthogonal cover Walsh codes among the orthogonal cover Walsh codes are mapped respectively to two ACK/NACK channel indexes transmitted using an even-numbered cyclic shift values among the cyclic shift values, and a second orthogonal cover Walsh code is mapped to one ACK/NACK channel index transmitted using an odd-numbered cyclic shift value among the cyclic shift values, and wherein the first orthogonal cover Walsh code is [+1 +1 +1 +1], the second orthogonal cover Walsh code is [+1 −1 +1 −1], and the third orthogonal cover Walsh code is [+1 −1 −1 +1].