Low-complexity channel estimation for OFDM systems in high-mobility fading channels

Abstract

Nowadays, multicarrier transmission is very popular because of the high data rate requirement of wireless systems. Orthogonal frequency-division multiplexing (OFDA) is a special case of multicarrier transmission. It is considered an effective technique for frequency-selective channels because of its spectral efficiency, its robustness in different multipath propagation environments, and its ability of combating intersymbol interference. Losing subchannel orthogonality causes interchannel interference, but, many conventional channel estimators assume that the channel is time-invariant during one OFDM symbol. This assumption causes error floors along the OFDM symbol for high-mobility cases. In this paper, we propose 2-dimensional pilot symbol-assisted channel estimation for wireless OFDM systems by using frequency and tune-domain interpolation. This method has the advantage of minimizing the system, complexity and processing delay while closely approximating the actual mobile channel. The performance of our proposed method is compared to coherent modulation with perfect channel estimation as well as other conventional channel estimation methods. Different detection techniques were used to test our proposed channel estimation algorithm.