Low-complexity channel estimation for LTE-based systems in time-varying channels

Abstract

For its key role in achieving high data rates, the need to develop a low-complexity channel estimator is one of the main targets in the Long-Term Evolution (LTE) research development. With high-mobility users in LTE-Orthogonal Frequency Division Multiplexing (LTE-OFDM) systems, channel estimator design becomes a challenging problem, since the estimator needs to estimate more channel parameters than in slow fading channels, which may make the channel estimation impractical. A low-complexity channel estimator is developed for LTE high-mobility systems based on the Piecewise Linear (PWL) model and the channel time-frequency correlation relationships. The channel estimator and interpolator is tested under different LTE channel models for various mobile velocities and showed an improvement in the Bit Error Rate (BER) performance from 6% to 2% compared to the conventional linear interpolation technique with only 33.2% increase in the required processing time for a doppler frequency of 300 Hz. The proposed interpolation technique is insensitive to the change in the mobile velocity to some extent; this makes the channel estimator more practical and robust to any change in the channel statistics.