A user equipment (UE) is described. The UE includes a processor and memory in electronic communication with the processor. The UE receives a configuration message of processing time reduction from an evolved node B (eNB). The UE also receives a physical downlink control channel (PDCCH) downlink control information (DCI) for a physical downlink shared channel (PDSCH) with reduced processing time in subframe n−k, where k is smaller than 4. The UE further determines a physical uplink control channel (PUCCH) resource for hybrid automatic repeat request-acknowledgement (HARQ-ACK) reporting. The UE additionally determines HARQ-ACK bits to be reported in subframe n. The UE also transmits the HARQ-ACK in subframe n on the determined PUCCH resource.