Disclosed are a user equipment unit, and a low-delay communication method and device for use in a terminal. First, a UE unit receives K wireless signal sets, and K is a positive integer greater than 1. Next, an uplink signaling is transmitted, and the uplink signaling includes HARQ-ACK information. Lengths of eTTIs corresponding to the K wireless signal sets correspond to K time lengths, respectively. Any two of the K time lengths are not equal. The HARQ-ACK information indicates whether encoding blocks in the K wireless signal sets are correctly encoded. The number of wireless signals contained in the K wireless signal sets are Q1, …, and QK, respectively. Q1, …, and QK are positive integers. The invention prevents a UE unit from transmitting multiple unlink signaling simultaneously, thereby enhancing robustness of HARQ-ACK at limited power. Moreover, the invention reduces air interface overheads, thereby increasing transmission efficiency.