Orthogonal frequency-division multiplexing (OFDM) is a digital multi-carrier modulation technique that partitions the available bandwidth into multiple orthogonal sub-carriers. Each sub-carrier is modulated with a conventional modulation scheme at a low symbol rate and maintains similar data rates as single-carrier modulation in the same bandwidth. OFDM provides advantages like easy adaptation to severe channel conditions, robustness against interference and fading, and high spectral efficiency through FFT implementation. Some disadvantages include sensitivity to Doppler shift and frequency synchronization errors. OFDM has been used in various wireless and wired communication systems.