IFFT Concept in OFDM

1. What is IFFT in OFDM?
2. What is the purpose of IFFT?
3. Why IFFT and FFT is used in OFDM?
4. What is the need for using FFT in OFDM?

What is IFFT in OFDM?

The IFFT output is the summation of all N sinusoids. 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.

What is the purpose of IFFT?

IFFT stands for Inverse Fast Fourier Transform. IFFT converts frequency domain vector signal to time domain vector signal. It is used after the modulator block in the OFDM Transmitter.

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.

What is the need for using FFT in OFDM?

Using FFT algorithms provides speed enhancements for data processing for OFDM systems. This technique is being used for Digital Audio Broadcasting (DAB), Digital Video Broadcasting (DVB), Wireless Local Area Network (WLAN), Wireless Metropolitan Area Network (WMAN), Multi Band-OFDM Ultra Wide Band (MB-OFDM-UWB) etc.