Data transmission method, apparatus and system for

Embodiment discloses a data transmission method, apparatus and system of the present invention, the data transmission method comprising: determining data to be transmitted associated with the user equipment resides in a relay station on the control plane signaling; by the relay station and the first user data bearer established between the donor base station transmitting the data to be transmitted, the first user data bearer provides integrity protection for the data to be transmitted. Embodiment implements control plane signaling associated with the user equipment resides in a relay station between the relay station and transmission of the donor base station, integrity protection can be obtained, denial of service attacks can be avoided by the present invention.