A user equipment receives first signaling from a base station through a physical downlink shared channel (PDSCH), and receives second signaling from the base station through a physical downlink control channel (PDCCH) or an enhanced physical downlink control channel (ePDCCH), where the first signaling includes a first time division duplexing TDD uplink-downlink configuration, and the second signaling includes a second TDD uplink-downlink configuration; the user equipment determines, according to the first TDD uplink-downlink configuration, an uplink subframe for sending a random access message; and the user equipment sends the random access message to the base station in the determined uplink subframe.