Simple Doppler Spread Compensator for Future Railway Mobile Communication Systems (FRMCS)

Abstract

The high speed railway technology is one of the important part of future railway system such as future railway mobile communication systems (FRMCS) that is based on the fifth telecommunication generation new radio (5G NR). FRMCS is suffering from the Doppler effect that causes random frequency in the received signal. Doppler effect damages the symbol orthogonality due to the change of channels within the duration of one orthogonal frequency division multiplexing (OFDM) symbol in high speed transceiver. In this paper, the Doppler Spread Compensator (DSC) technology is proposed for FRMCS, where interpolator based on Minimum Mean Square Error (MMSE) and array antenna are used to assist the DSC. This DSC technique plays an important role in the high speed railway technology to compensate the Doppler effect. We evaluate performance of the system in terms of bit-error-rate (BER) using a series of computer simulations. We also evaluate the performance of DSC assisted by array antenna elements. We confirmed from simulations that the proposed simple DSC works well even though the railway is accommodating objects with high speed of 500 km/h. The results confirmed that the array antenna helps to improve the performance of FRMCS and as a reference for the developments and implementations of antenna arrays and DSC for FRMCS.