A user equipment (UE) for transmitting signals in a Licensed-Assisted Access (LAA) serving cell is described. The UE includes a processor and memory in electronic communication with the processor. Instructions stored in the memory are executable to receive an uplink (UL) grant from a downlink control information. The instructions are also executable to determine a UL contention access region based on the UL grant. The instructions are further executable to determine clear channel assessment (CCA) timeslots in the UL contention access region. The instructions are additionally executable to perform UL contention access in the UL contention access region with a backoff process.