Low complexity MMSE estimator for OFDM systems over slow fading Rayleigh channels

Orthogonal Frequency Division Multiplexing (OFDM) is adopted widespread for wireless and wired communication systems because of its inherent feature of the spectral efficiency and robustness to channel impairments. The throughput deterioration of the OFDM system due to pilots can be reduced by minimizing the density of pilots. A novel Low Overhead Pilot Insertion (LPI) scheme is proposed for OFDM system over slow fading channels without compromising on the Bit Error Rate (BER) performance. Modified Minimum Mean Square Error (M-MMSE) estimator with low computational complexity based on LPI scheme is also proposed. The pilot overhead in LPI scheme is reduced to 51.56% as compared to block-type channel estimation for the same BER performance. The simulation time taken for computing the channel frequency response by M-MMSE estimator with the proposed LPI scheme is reduced to approximately 14.28 % as compared to MMSE estimator for block-type pilot arrangement.