Comparisons of low complexity transforms for multi carrier schemes

Multi carrier modulation (MCM) transmits the data by dividing the data streams into several bit streams, and these sub streams are used to modulate several carriers. MCM is highly useful in high data rate wireless communication system. Orthogonal frequency division multiplexing is the widely implemented MCM technique for current wireless systems. All system faces the complexity reduction issues, as the number of sub carrier increases and also in high peak to average power ratio (PAPR) & bit error rate (BER) performance. In this paper, we present the comparisons of different low complexity transforms which includes direct computation of discrete Fourier transform (DFT), radix 2 Fast Fourier transform (FFT), divide and conquer algorithm, WHT-DFT transform and combined T-transform. This comparison includes the multiplication and addition complexity values for given transforms with their methodologies and comparing it with the simulation results.