DFT based Channel Estimation in OFDM System

Abstract

Multi carrier modulation is Orthogonal Frequency Division Multiplexing (OFDM), dividing the large band spectrum into small (narrow) band spectrum. OFDM offers flexibility in adaptation to time varying channel condition by adopting the parameters at each subcarrier accurately. Due to the multipath effect the OFDM system suffers Inter Symbol Interference (ISI).ISI can be reduced by introducing the guard band (cyclic prefix).Time-varying channel estimation is an important activity in next generation wireless communication. Channel estimation is required mainly for the significant signal processing operation in multiple input multiple output MIMO- OFDM systems. In this project DFT – based channel estimation based on block type arrangement is implemented in MAT Lab. The bit error rate (BER) of DFT (Discrete Fourier Transform)based channel estimation is less than the BER of LS (Least Square) and MMSE (Minimum Mean Square Error) based channel estimation with same signal to noise ratio (SNR).