A communication device, comprising: a transceiver , configured to send a transmission frame to a second communication device, wherein the transmission frame comprises a first part and a second part, wherein the first part of the transmission frame comprises a preamble part of the transmission frame, the second part of the transmission frame comprises a data part of the transmission frame, and the data part of the transmission frame includes data information; and the preamble part of the transmission frame carries information required for the second communication device to demodulate the second part of the transmission frame; wherein the preamble part of the transmission frame comprises a legacy short training field, L-STF, a legacy long training field, L-LTF, legacy signaling, L-SIG, and a high efficiency wireless local area network signaling, HEW-SIG, wherein the HEW-SIG carries the information required for the second communication device to demodulate the second part of the transmission frame; the transceiver sends the first part of the transmission frame by using a first quantity of subcarriers, the transceiver sends the second part of the transmission frame by using a second quantity of subcarriers, and the first quantity is not equal to the second quantity; wherein the transmission bandwidths used by the first part and the second part of the transmission frame are equal, and a spacing of the first quantity of subcarriers is not equal to a spacing of the second quantity of subcarriers, the spacing of the first quantity of subcarriers being 312.5kHz; wherein the spacing of the first quantity of subcarriers is greater than the spacing of the second quantity of subcarriers. a transceiver , configured to send a transmission frame to a second communication device, wherein the transmission frame comprises a first part and a second part, wherein the first part of the transmission frame comprises a preamble part of the transmission frame, the second part of the transmission frame comprises a data part of the transmission frame, and the data part of the transmission frame includes data information; and the preamble part of the transmission frame carries information required for the second communication device to demodulate the second part of the transmission frame; wherein the preamble part of the transmission frame comprises a legacy short training field, L-STF, a legacy long training field, L-LTF, legacy signaling, L-SIG, and a high efficiency wireless local area network signaling, HEW-SIG, wherein the HEW-SIG carries the information required for the second communication device to demodulate the second part of the transmission frame; the transceiver sends the first part of the transmission frame by using a first quantity of subcarriers, the transceiver sends the second part of the transmission frame by using a second quantity of subcarriers, and the first quantity is not equal to the second quantity; wherein the transmission bandwidths used by the first part and the second part of the transmission frame are equal, and a spacing of the first quantity of subcarriers is not equal to a spacing of the second quantity of subcarriers, the spacing of the first quantity of subcarriers being 312.5kHz; wherein the spacing of the first quantity of subcarriers is greater than the spacing of the second quantity of subcarriers. <EOS>