FIG. 14 is a diagram illustrating an assignment of different offsets for determining a PUCCH resource for HARQ-ACK transmission associated with different DMRS antenna ports, according to an embodiment of the present invention.
Referring to FIG. 14, a first LCCE and a DMRS port for a transmission of a first EPDCCH to a first UE are, respectively, nLCCE and NDMRS1 1410, while a first L-CCE and a DMRS port for a transmission of a second EPDCCH to a second UE are, respectively, nLCCE and NDMRS2 1420. Each of the previous two EPDCCHs is associated with a respective PDSCH. The first UE determines a first PUCCH resource for a HARQ-ACK signal transmission in response to the detection of the first EPDCCH as nPUCCH(1)=nLCCE+NPUCCHE,NDMRS1 1430, where NPUCCHE,NDMRS1 is the PUCCH resource offset associated with NDMRS1. The second UE determines a second PUCCH resource for a HARQ-ACK signal transmission in response to the detection of the second EPDCCH as nPUCCH(2)=nLCCE+NPUCCHL,NDMRS2 1440, where NPUCCHL,NDMRS2 is the PUCCH resource offset associated with NDMRS2. Therefore, even though multiple EPDCCHs may have a same LCCE as a first one for their transmissions, a one-to-one mapping exists among EPDCCHs 1450 and respective PUCCH resources 1460, and collisions can be avoided.
