Apparatuses, methods, and systems are disclosed for transmission repetition reduction. One apparatus includes a transmitter that transmits a Physical Downlink Shared Channel ("PDSCH" ) transport block ( "TB" ) in a first set of subframes to a device. In such an embodiment, a second set of subframes may be a proper subset of the first set of subframes. In various embodiments, the apparatus includes a receiver that receives a positive acknowledgement from the device using a first hybrid automatic repeat request acknowledgement ( "HARQ-ACK" ) resource. In such embodiments, the positive acknowledgement may indicate that the PDSCH TB is correctly decoded from the second set of subframes. In certain embodiments, the apparatus includes a processor that determines a correspondence between the first HARQ-ACK resource and the second set of subframes.