Patent ID: 9578627
Date: 2017-02-21
CPC Classifications: H04L,H04W

Claim:
1. A method for transmitting Acknowledgement/Negative Acknowledgement (ACK/NACK) information at a User Equipment (UE) configured to use a Physical Uplink Control Channel (PUCCH) format 3 in a wireless communication system, the method comprising: determining a PUCCH format and a PUCCH resource through which ACK/NACK information for downlink transmission in a downlink frame set including M downlink subframes is to be transmitted, where M≧1; transmitting, without a scheduling request (SR), the ACK/NACK information using the PUCCH format and the PUCCH resource in one uplink subframe, wherein more than one serving cell is configured for the UE and the more than one serving cell includes one Primary Cell (PCell) and at least one Secondary Cell (S Cell), and wherein the UE is using the PUCCH format 3; and changing, by the UE, from using the PUCCH format 3 to a PUCCH format 1a/1b to transmit the ACK/NACK information by using the PUCCH format 1a/1b, when both one Physical Downlink Shared Channel (PDSCH), indicated by a detection of a corresponding Physical Downlink Control Channel (PDCCH), is present only on the PCell in the downlink subframe set, and a Downlink Assignment Index (DAI) value in the PDCCH is equal to 1.