The Effect of Coding on OFDM and Single Carrier Transmission with Decision Feedback Equalizer

Single carrier transmission (SCT) is a competing technique for orthogonal frequency division multiplexing (OFDM) in broadband wireless systems (BWS). Recent developments in frequency domain equalization (FDE) using decision feedback equalization (DFE) have greatly improved the system based on the single carrier (SC) technique. This paper presents the comparison of the effect of coding on OFDM and SCT with DFE. SC-linear equalizer (SC-LE) and SC-DFE techniques are compared with OFDM-cyclic prefix (OFDM-CP), OFDM-zero padding (OFDM-ZP). BER performance of these four techniques are compared with the coded version of the each. 1/2 rate conventional code and Viterbi decoding are used to simulate the coding gain. A wireless local area network (WLAN) system was simulated for frequency selective fading channel model with and without Inter symbol interference (ISI) encounter. Moreover CP and ZP variants of both OFDM and SC-DFE are simulated to compare the coding gains. More coding gain is comparatively achieved by the SC-DFE when ISI is encountered and by the OFDM when ISI is not encountered.