Developments in orthogonal frequency division multiplexing (OFDM) system-a survey

In today's communication scenario, high data rate single-carrier transmission may not be feasible due to too much complexity of the equalizer in the receiver. To overcome the frequency selectivity of the wideband channel experienced by single-carrier transmission, multiple carriers can be used for high rate data transmission. Orthogonal frequency division multiplexing (OFDM), is multicarrier system which has become a modulation in physical layer of next generation WiMAX, LTE system. In this paper effort is made to present challenges in OFDM and work done so far in channel equalisation and different transforms used in OFDM system.