Wireless communication for heavy haul railway tunnels based on directional antenna radiating same direction

Radio-over-fiber (RoF) technology is a comparatively mature technology which can effectively improve the reliability and quality of service (QoS) in railway communication systems. As a coverage strategy of RoF in long heavy haul railway tunnels (more than 1 km), directional antenna radiating same direction is highly valued. Due to the handover mechanism changed, handover trigger probability and outage probability will be adopted to investigate its performance. Compared with the traditional model, this strategy, which deployed by a number of RAUs (remote antenna unit) using directional antenna in long tunnels, has its own advantages. It can be concluded that when using directional antenna radiating same direction, the trigger probability can almost reach 100% when entering the overlapping area and the outage probability is lower.