A fast fading channel estimation scheme for OFDM with sparse and scattered pilot symbols

Abstract

OFDM (orthogonal frequency division multiplexing) can utilize one-tap equalization for multipath (frequency selective) fading and is widely used in many wireless systems today. However, according to the demand for high-mobility communication and the use of higher carrier frequency, the influence of time selectivity of fading is increasing. Therefore, an accurate channel estimation of time and frequency selective fading is important for OFDM systems. To achieve this requirement, we have proposed a fading estimation scheme FFT to scattered pilot symbols in OFDM. However, the estimation accuracy of this scheme changes by the estimation order of the time and frequency direction, maximum Doppler frequency, and delay spread of fading. Therefore, in this paper, we propose an efficient fast fading channel estimation scheme for OFDM with an adaptive order switching. The performances of the proposed scheme are evaluated by computer simulations.