OFDM Modulation what's the output of the FFT?

1. What does FFT do in OFDM?
2. What is FFT size in OFDM?
3. Why IFFT and FFT is used in OFDM?
4. How does OFDM provide high data rate?

What does FFT do in OFDM?

Implementation of OFDM deals with application of Fast Fourier Transform (FFT) to modulation and demodulation processes to generate carriers orthogonal to each other. In conventional system, IFFT (Inverse Fast Fourier Transform) is used at transmitter side and FFT is used in receiver side.

What is FFT size in OFDM?

For this version the FFT size is fixed at 256, which 192 subcarriers used for carrying data, 8 used as pilot subcarriers for channel estimation and synchronization purposes, and the rest used as guard band subcarriers.

Why IFFT and FFT is used in OFDM?

The OFDM signal is generated by implementing the Inverse Fast Fourier Transform (IFFT) at the transmitter which is used to convert frequency domain to time domain and Fast Fourier Transform (FFT) which is used to convert time domain to frequency domain at the receiver side is implemented.

How does OFDM provide high data rate?

By transmitting a large number of separate carriers, each conveying a low data rate stream, OFDM can attain high data rates. By properly choosing the symbol duration and carrier spacing, efficient modulation and demodulation of the signal is possible.