PUCCH resource determination for HARQ-ACK transmission in response to ePDCCH-scheduled PDSCH or ePDCCH-indicated SPS release in a TDD radio communication system. Downlink control information (DCI) is received in a downlink subframe via an Enhanced Physical Downlink Control Channel (ePDCCH). A resource index for a Physical Uplink Control Channel (PUCCH) resource is determined, based on the lowest enhanced Control Channel Element (eCCE) index of the received DCI, a device-specific offset value, and an index i that identifies the downlink subframe in a pre-determined set of one or more downlink subframes associated with an uplink subframe. The PUCCH resource is determined according to a formula that results in a sequential allocation of PUCCH resources in the uplink subframe with respect to the downlink subframes associated with the uplink subframe, for each of a plurality of sets of ePDCCH resources. HARQ feedback is transmitted in the uplink subframe, in the indexed PUCCH resource.