  The Tunka Radio Extension (Tunka-Rex) is a digital antenna array (63 antennas
distributed over 1km^2) co-located with the TAIGA observatory in Eastern
Siberia. Tunka-Rex measures radio emission of air-showers induced by ultra-high
energy cosmic rays in the frequency band of 30-80 MHz. Air-shower signal is a
short (tens of nanoseconds) broadband pulse. Using time positions and
amplitudes of these pulses, we reconstruct parameters of air showers and
primary cosmic rays. The amplitudes of low-energy event (E<10^17 eV) cannot be
used for successful reconstruction due to the domination of background. To
lower the energy threshold of the detection and increase the efficiency, we use
autoencoder neural network which removes noise from the measured data. This
work describes our approach to denoising raw data and further reconstruction of
air-shower parameters. We also present results of the low-energy events
reconstruction with autoencoder.
