A user equipment (UE) receives a first dynamic resource allocation on a first channel (PDCCH), then sends data according to the first resource allocation. During a time at which an ACK/NACK for the sent data is scheduled to occur on a second channel (PHICH), the UE is engaging in an activity that takes priority over the ACK/NACK. The UE then receives a second dynamic resource allocation on the first channel and determines the ACK/NACK for the sent data from the second dynamic resource allocation. The determining can be direct, as in receiving a zero-valued resource allocation; or it may be indirect as in mapping the second dynamic resource allocation to the second channel and receiving the acknowledgement on the second channel after that mapping. Also detailed are similar mirror actions from the Node B's perspective, as well as apparatus, methods, and embodied computer programs.