User equipment , comprising: a processor , configured to determine a frame structure of a serving cell of a Time Division Duplexing, TDD, system according to an uplink-to-downlink ratio of the serving cell, wherein different uplink-to-downlink ratios are corresponding to different frame structures, and frames corresponding to different frame structures have different composition, each radio frame corresponding to one of the different frame structures comprises at least one downlink subframe, at least one uplink subframe, and at least one special subframe, the special subframe is a first special subframe or a second special subframe, the at least one downlink subframe comprises a subframe l , the at least one uplink subframe comprises a subframe 1+4, the at least one special subframe comprises a subframe l +5, and the subframe l +5 is the first special subframe, wherein l is a positive integer, l is an odd multiple of 5, and l is a subframe number; and a transceiver , configured to send or receive information in the serving cell based on the frame structure determined by the processor , wherein the special subframe comprises a time domain symbol used for downlink transmission, a guard period, and a time domain symbol used for uplink transmission, a quantity of time domain symbols used for downlink transmission is greater than a quantity of time domain symbols used for uplink transmission in the first special subframe, a quantity of time domain symbols used for downlink transmission is less than a quantity of time domain symbols used for uplink transmission in the second special subframe, the time domain symbol used for downlink transmission comprises physical downlink control channel transmission, and the time domain symbol used for uplink transmission comprises hybrid automatic repeat request-acknowledgment, HARQ-ACK, transmission. a processor , configured to determine a frame structure of a serving cell of a Time Division Duplexing, TDD, system according to an uplink-to-downlink ratio of the serving cell, wherein different uplink-to-downlink ratios are corresponding to different frame structures, and frames corresponding to different frame structures have different composition, each radio frame corresponding to one of the different frame structures comprises at least one downlink subframe, at least one uplink subframe, and at least one special subframe, the special subframe is a first special subframe or a second special subframe, the at least one downlink subframe comprises a subframe l , the at least one uplink subframe comprises a subframe 1+4, the at least one special subframe comprises a subframe l +5, and the subframe l +5 is the first special subframe, wherein l is a positive integer, l is an odd multiple of 5, and l is a subframe number; and a transceiver , configured to send or receive information in the serving cell based on the frame structure determined by the processor , wherein the special subframe comprises a time domain symbol used for downlink transmission, a guard period, and a time domain symbol used for uplink transmission, a quantity of time domain symbols used for downlink transmission is greater than a quantity of time domain symbols used for uplink transmission in the first special subframe, a quantity of time domain symbols used for downlink transmission is less than a quantity of time domain symbols used for uplink transmission in the second special subframe, the time domain symbol used for downlink transmission comprises physical downlink control channel transmission, and the time domain symbol used for uplink transmission comprises hybrid automatic repeat request-acknowledgment, HARQ-ACK, transmission. <EOS>