Embodiments herein provide an OFDMA method for performing OFDM based communication in a wireless communication system. The OFDMA method includes splitting a carrier bandwidth into a number of subbands and modulating resource units in each of the subbands with data symbols in a parallel manner. Further, multiplexing the resource units by transforming each of the modulated resource units through a plurality of unitary transformations at a stage. Further, generating an output by performing a parallel to serial conversion of the transformed resource units. Further, the OFDMA method includes generating an OFDM signal by multiplexing an output from at least one of the previous stage to another stage by transforming the output through a unitary transformation for a defined number of times. Furthermore, the OFDMA method includes transmitting the OFDM signal over a wireless channel in the wireless network system.