A low-complexity SNR estimation algorithm and channel estimation method for OFDM systems

Abstract

This paper proposes a novel signal-to-noise ratio (SNR) estimation algorithm for orthogonal frequency division multiplexing (OFDM) systems in the doubly selective channels by inserting special preambles. The noise variance is estimated by one preamble symbol in time domain. Besides, the estimated noise variance can be utilized as initial noise power for iterative linear minimum mean square error (LMMSE) channel estimation. Simulation results show that this new algorithm is insensitive to the Doppler frequency and is robust in large Doppler frequency environments, and has a lower computational complexity than other methods.