A Novel Adaptive Pilot Placement Algorithm for Channel Estimation in OFDM Based Systems

Abstract

The orthogonal frequency division multiplexing (OFDM) system, which is one of the multicarrier communication systems, has been widely used due to its ability to provide high-speed data communication using bandwidth effectively and its resistance to echo delays. In OFDM system, the disturbing effects of the wireless communication channel can be reduced by estimating the channel in the receiver. In this study, a novel channel estimation method with a pilot placement algorithm which can adaptively change according to the structure of the channel is proposed for the OFDM system. The proposed algorithm is based on placing the pilot signals more frequently in the regions with deep fading of the channel. From the simulation results, it is seen that the proposed adaptive channel estimation algorithm gives better results than the classical channel estimation algorithms, and provides an improvement of up to 11.6 dB in bit error rate (BHO) performance. In addition, unlike the studies in the literature, a new mathematical expression is proposed in the last part of the study to determine the threshold level of the regions where the pilot frequency will be increased in the frequency domain of channel.