An information processing apparatus, comprising an inverse fast Fourier transform IFFT module, a precoding module, and a determining module, wherein the IFFT module is configured to separately perform IFFT processing on N frequency-domain data streams to acquire N time-domain data streams, wherein N is a positive integer; the precoding module is configured to perform precoding processing on the N time-domain data streams to acquire a precoding processing result; and the determining module is configured to determine, according to the precoding processing result, an orthogonal frequency division multiplexing OFDM symbol that needs to be sent over each antenna of M antennas, so that an information transmission apparatus sends, by using each antenna of the M antennas, the OFDM symbol that needs to be sent over each antenna, wherein M is a positive integer greater than N; and characterized in that: the N time-domain data streams are carried over S subbands, wherein S is a positive integer greater than or equal to 2, N is a positive integer greater than or equal to 2, and the subbands are configured to carry one or more time-domain data streams; the precoding module is specifically configured to: separately perform precoding processing on a time-domain data stream carried over each subband of the S subbands by using a 2-dimensional precoding matrix, to acquire the precoding processing result, wherein the precoding processing result comprises a useful part, which is obtained by using the time-domain data stream carried over each subband, of the OFDM symbol that needs to be sent over each antenna; and the determining module is specifically configured to: perform addition processing on useful parts, which are obtained by using the time-domain data streams carried over the S subbands, of OFDM symbols that need to be sent over a same antenna, to obtain an addition processing result corresponding to each antenna, and perform cyclic shift processing on the addition processing result corresponding to each antenna, to obtain the OFDM symbol that needs to be sent over each antenna. the N time-domain data streams are carried over S subbands, wherein S is a positive integer greater than or equal to 2, N is a positive integer greater than or equal to 2, and the subbands are configured to carry one or more time-domain data streams; the precoding module is specifically configured to: separately perform precoding processing on a time-domain data stream carried over each subband of the S subbands by using a 2-dimensional precoding matrix, to acquire the precoding processing result, wherein the precoding processing result comprises a useful part, which is obtained by using the time-domain data stream carried over each subband, of the OFDM symbol that needs to be sent over each antenna; and the determining module is specifically configured to: perform addition processing on useful parts, which are obtained by using the time-domain data streams carried over the S subbands, of OFDM symbols that need to be sent over a same antenna, to obtain an addition processing result corresponding to each antenna, and perform cyclic shift processing on the addition processing result corresponding to each antenna, to obtain the OFDM symbol that needs to be sent over each antenna.