Date Added: Jun 2012
OFDM is a multicarrier modulation technique in which a high rate bitstream is split into N parallel bitstreams of lower rate and each of these are modulated using one of N orthogonal sub-carriers. In a basic communication system, the date is modulated onto a single carrier frequency. The available bandwidth is then totally occupied by each symbol. This kind of system can lead to InterSymbol-Interference (ISI) in case of frequency selective channel. The basic idea of OFDM is to divide the available spectrum into several orthogonal sub channels so that each narrowband subchannels experiences almost flat fading. Orthogonal Frequency Division Multiplexing (OFDM) is becoming the chosen modulation technique for wireless communications.