Design and Implementation of OFDM System and Reduction of Inter-Carrier Interference at Different Variance

Orthogonal frequency division multiplexing (OFDM) is one of the multi-carrier modulation (MCM) techniques that transmit signals through multiple carriers. These carriers (subcarriers) have different frequencies and they are orthogonal to each other. Orthogonal frequency division multiplexing techniques have been applied in both wired and wireless communications, such as the asymmetric digital subscriber line (ADSL) and the IEEE 802.11 standard. ICI reduction techniques achieve a better SNR and BER in OFDM at zero phase noise variance. This technique will use a large number of closely spaced orthogonal subcarriers to avoid phase noise. It provides high data rates with sufficient robustness to radio channel damages. A major problem in OFDM is carrier frequency offset error between the transmitted and received signals. Due to this the orthogonality of the subcarriers is no longer maintained which results in ICI (Inter carrier Interference). In this paper, we used the ICI self-cancellation technique and reduced the ici (show the precentage improvement graph) and calculate the SNR=15db and 20db at different phase noise variance.