The use of spatial multiplexing for transmissions of EPDCCHs associated with PDSCHs to respective UEs results in PUCCH resource collision for respective HARQ-ACK signal transmissions under the conventional PUCCH resource determination. Denoting the first EPDCCH ECCE as n_ECCE, the PUCCH resource for HARQ-ACK signal transmission is n_PUCCH^E=n_ECCE+N_PUCCH^E, where N_PUCCH^E is an offset a NodeB informed to UEs through higher layer signaling. N_PUCCH^E may be the same as N_PUCCH or it may be separately configured for EPDCCH operation. When n_ECCE is the same for UEs with spatially multiplexed EPDCCH transmissions associated with respective PDSCHs, the PUCCH resource for each respective HARQ-ACK signal transmission is the same.

The previous PUCCH resource collision problem is further exacerbated when a UE is configured antenna transmission diversity for HARQ-ACK signal transmissions and a different PUCCH resource is required for each antenna. For two antennas, a conventional method is to obtain a PUCCH resource for the first antenna as for the case of a single antenna, n_PUCCH=n_ECCE+N_PUCCH, and obtain a PUCCH resource for the second antenna as n_PUCCH=n_ECCE+1+N_PUCCH. Due to the limited number of ECCEs per PRB, such as 4 ECCEs per PRB, the PUCCH resource collision problem for transmitter antenna diversity exists regardless of the use of spatial multiplexing for EPDCCH transmissions.