A data transmission apparatus, applicable to a UE, the apparatus includes a receiver configured to receive configuration information about data radio bearers (DRBs), the configuration information indicating TTI length to which each DRBs for the UE corresponds, the DRBs being configured by radio resource control (RRC), and receive one or more uplink grant, each of the uplink grants of the one or more uplink grants corresponding to a TTI length different from another TTI length of another uplink grant, a transmitted configured to transmit data using an uplink shared channel corresponding to each TTI length according to an uplink grant in the one or more uplink grants.