First element of the complex input array for the IFFT with OFDM

1. What is the use of Ifft in OFDM?
2. Why the system implementation of OFDM uses IFFT and FFT in its processing?

What is the use of Ifft in OFDM?

Thus, the IFFT block provides a simple way to modulate data onto N orthogonal subcarriers. The block of N output samples from the IFFT make up a single OFDM symbol. After some additional processing, the time-domain signal that results from the IFFT is transmitted across the radio channel.

Why the system implementation of OFDM uses IFFT and FFT in its processing?

The complexity of the oscillators and demodulator increases as the number of sub-carriers increase. The implementation of OFDM through the use of IFFT/FFT algorithm greatly reduces the cost, size of the system and complexity; the IFFT/FFT has the computational capability to handle as many sub-carriers as possible.