Downlink data transmission for high‐speed trains in 5G communication systems

Abstract

In this study, a new transmitter–receiver approach for high-speed train (HST) downlink orthogonal frequency division multiplexing (OFDM) data transmission and detection in fifth generation (5G) communication systems is proposed. The proposed method uses a new Doppler shift frequency (DSF) estimation method, proposed in this study, to calculate the channel tap DSFs at the HST receiver. These estimated DSFs are used to calculate the channel taps’ angle of departure (AoD). Using the projected AoDs, the transmitter beamformer adjusts its coefficients to suppress the non-line-of-sight (NLoS) channel taps and a DSF compensation block is used to mitigate the line-of-sight channel tap DSF. Simulation results indicate the fidelity of the proposed DSF estimation method and the proposed transmitter–receiver approach. Due to the accuracy of the proposed DSF estimation method and the effectiveness of the beamformer in suppressing the NLoS channel taps, the approach of using a classic digital modulation and demodulation method instead of the OFDM scheme is appraised. Simulation results indicate that this shift from the OFDM modulation to the classic modulation results in a data detection approach which has acceptable accuracy, low computational complexity, and high spectral efficiency.