OFDM Channel Estimation Enhancement using Null Subcarriers

Abstract

Orthogonal frequency division multiplexing (OFDM) is one of the popular techniques for high data rates nowadays. However, the channel transfer function estimation for OFDM based systems is essential, to increase the bit rate with low bit error rate (BER) degradation. Numerous algorithms are provided in the literature such as the pilot assisted channel estimation methods. This paper suggests to making use of the null subcarriers, such as the cyclic prefix interval, to make more occupation of the pilot subcarriers. Least squares estimator has been employed to estimate the channel frequency response. However, simulation results, using MATLAB programming, show that the BER performance has been improved, where the required signal to noise ratio (SNR) has been reduced by approximately 4dB, for different baseband mapping.