Embodiments of the present invention are described in detail with reference to the accompanying drawings. The same or similar components may be designated by the same or similar reference numerals although they are illustrated in different drawings. Further, various specific definitions found in the following description are provided only to help a general understanding of the present invention, and it is apparent to those skilled in the art that the present invention can be implemented without such definitions. Detailed descriptions of constructions or processes known in the art may be omitted to avoid obscuring the subject matter of the present invention.

Additionally, although the embodiments of the present invention are described below with reference to OFDM and Discrete Fourier Transform Spread OFDM (DFT-S-OFDM), they also are applicable to all Frequency Division Multiplexing (FDM) transmissions in general.

A first embodiment of the present invention considers methods for multiplexing PUCCH resources in response to detections of PDCCHs and EPDCCHs associated with respective PDSCHs. The first embodiment of the invention also considers a UE apparatus for determining a PUCCH resource for a HARQ-ACK signal transmission in response to a detection of an EPDCCH associated with a PDSCH, and for determining whether a PRB is used to transmit EPDCCH or PDSCH in a subframe.

In the following description, an ECCE is categorized as a DCCE if it is allocated to a distributed EPDCCH, and is categorized as an LCCE if it is allocated to a localized EPDCCH. A DCCE may or may not have the same size as an LCCE. Moreover, unless explicitly mentioned, for the embodiments of the present invention an EPDCCH transmission is assumed to always be associated with a respective PDSCH transmission or a release of an SPS PDSCH transmission.