An approach for 5G implementation in railways based on orthogonal time frequency space

Fifth Generation for Railways (5G-R) is a promising technology that seeks to improve safety, efficiency, and passenger experience by supporting a variety of services, such as real-time monitoring, predictive maintenance, autonomous operation, and passenger entertainment by accessing the Internet during trips, thus starting a new era of smart and efficient railway transportations. However, 5G-R suffers from the termed inter-carrier interference (ICI) problem due to the Doppler shift phenomenon especially when operating in high-mobility environments, such as high-speed railway (HSR) as it depends on orthogonal frequency division multiplexing (OFDM) technology. Our aim in this paper is to reduce the Doppler shift effect in the 5G-R system environment by incorporating the orthogonal time frequency space (OTFS) technology. Recently, OTFS was introduced as an effective ICI canceler. We referred to this solution as the OTFS-based 5G-R system. In order to verify the effectiveness of the proposed solution, we compare its performance with that based on OFDM in different HSR environments using quadrature amplitude modulation (QAM) schemes. Further performance evaluation process was conducted including the use of two different equalization techniques at the receiving side. Matlab was used to implement the aforementioned solution. Results confirmed the superiority of the proposed solution since it shows lower BER values. Results also confirmed the effectiveness of the proposed solution in reducing the Doppler effect because it almost shows identical performance regardless the difference in speeds.