Pilot design for channel estimation in Doubly Selective Channel

We consider pilot sequence designs for channel estimation in doubly-selective channels (DSC) which are modeled using the basis expansion model (BEM) approach. We propose to use pilot sequences (instead of impulse pilots) to reduce the peak-to-average power ratio (PAPR) of the transmitted signal. Specifically, by analysing the mean square error (MSE) metric of the BEM channel coefficients, we propose the use of Huffman sequences to reduce the PAPR during channel estimation. Furthermore, we show that a systematic re-arrangement of the pilot sequence within the transmission frame can significantly improve the channel estimation performance of the system, as compared to the conventional periodic pilot placement.