What technique does the transmitter use to realize ofdm

The transmitter uses FFT technology to realize ofdm.

OFDM (Orthogonal Frequency Division Multiplexing) that is, Orthogonal Frequency Division Multiplexing (OFDM), in fact, OFDM is a kind of MCM (Multi Carrier Modulation), Multi-Carrier Modulation.

OFDM technology is developed from MCM (Multi-Carrier Modulation).OFDM technology is one of the realization of multi-carrier transmission scheme, its modulation and demodulation are based on the IFFT and FFT to realize respectively, is the realization of the lowest complexity and the most widely used one of the multi-carrier transmission scheme.

In a communication system, the bandwidth that a channel can provide is usually much wider than the bandwidth required to transmit a one-way signal. It is wasteful to transmit only one signal over a channel, and in order to fully utilize the channel's bandwidth, frequency-division multiplexing (FDM) can be used.

The main idea of OFDM is to divide the channel into a number of orthogonal subchannels, convert the high-speed data signals into parallel low-speed sub-streams, and modulate them for transmission on each subchannel. The orthogonal signals can be separated by employing a correlation technique at the receiving end, which reduces the mutual interference (ISI) between the sub-channels. The signal bandwidth on each sub-channel is less than the correlation bandwidth of the channel, so flat fading can be viewed on each sub-channel, which eliminates inter-code crosstalk, and channel equalization is made relatively easy because the bandwidth of each sub-channel is only a small fraction of the original channel bandwidth.

OFDM technology, which is the basis of the HPA Alliance (HomePlug Powerline Alliance) industry specification, uses a discontinuous multi-tone technique to accomplish signaling by combining a large number of signals in different frequencies called carriers into a single signal. Because of its ability to transmit signals in the presence of spurious interference, this technology is often utilized in transmission media that are susceptible to or less resistant to outside interference.