This disclosure relates to the field of wireless communications technologies, and in particular, to an information transmission apparatus, method, and system. In a communications apparatus provided in an embodiment, a processing module is configured to determine a frame structure of a serving cell. In the determined frame structure, one radio frame includes at least one first subframe. The first subframe includes: a first part that includes a symbol used for downlink transmission; a second part that includes a guard period GP; and a third part that includes a symbol used for uplink transmission, and the uplink transmission includes uplink control information transmission; and a transceiver module is configured to send and receive information in the serving cell. The third part is used for uplink control information transmission.