Devices, methods, computer-readable media, and systems configurations for determining a hybrid automatic repeat request (HARQ)-acknowledgment (ACK) codebook in wireless communication networks. A user equipment (UE) may communicate with a plurality of serving cells, wherein at least two of the serving cells include different time division duplexing (TDD) uplink-downlink (UL-DL) configurations. The UE may determine a value based on a downlink assignment index (DAI), and determine a number of downlink subframes or special subframes that are included in a bundling window associated with an uplink subframe. Further, the UE may select the lesser of the determined value or the determined number of downlink subframes or special subframes included in the bundling window to correspond to a number of subframes for which the UE needs to feedback HARQ-ACK bits for the first serving cell.