Performance Analysis of Train-to-Train Emergency communication in Tunnel Based on Double hop Relaying

As for the high bit error rate (BER) problem of train-to-train (T2T) communication system caused by multipath effects under high-speed railway (HSR) tunnel scenario, we designed a T2T emergency communication physical layer model based on double hop relaying. To meet the needs of emergency communication, we planned a 3D space trajectory of relaying through the interval tracking analysis of train operation states. To reduce the effect of multipath on the performance of wireless transmission links, we established a multi-antenna transmission model which was composed of frequency shift key control modulation (FSK), space-time block coding (STBC), pilot estimation. According to the multipath delay power distribution obtained by deterministic model of the tunnel, we derived the expression of average BER and outage probability in double hop relaying. The simulation results show that the BER and outage probability of the link are in line with the safety business requirement for train control, which are obtained by setting the number of antennas and channel attenuation parameters. The research result of this paper provides a certain theoretical basis for the high reliability transmission of T2T communication.