Channel Estimation Strategy for LPWA Transmission at Low SNR: Application to Turbo-FSK

Turbo Frequency Shift Keying has been considered as a promising physical layer for low power wide- area network connectivity. Because of its constant envelope amplitude and the efficiency of its iterative receiver performance close to Shannon’s limit can be achieved. However, results published so far in the literature for the waveform have assumed perfect channel estimation or Signal-to- noise (SNR) levels that are higher than the SNR levels considered for these applications. This paper analyzes a channel estimation strategy based on a specifically adapted pilot sequence. Simulations have been performed to evaluate the performance of the proposed approach. Performance loss induced by imperfect channel estimation algorithms is estimated.