A data transmission method, device, and system are provided. The method includes: sending, by a base station, an NPSS to UE by using a first subframe in a first radio frame and a first subframe in a second radio frame, where the first radio frame and the second radio frame are consecutive, and both the first radio frame and the second radio frame use a TDD uplink-downlink subframe configuration; sending, by the base station, an NPBCH to the UE by using a second subframe in the first radio frame and a second subframe in the second radio frame; sending, by the base station, an NSSS to the UE by using a third subframe in the first radio frame; and sending, by the base station, a SIB1-NB to the UE by using a third subframe in the second radio frame.