Optically Backhauled Moving Network for Local Trains

The concept of moving cell in cellular systems has been discussed for 5G group mobility where rapidly moving platforms such as trains carry a large number of user terminals. It has been considered to employ wireless backhaul for moving cell, the problem of which is its limited and unstable bandwidth. To realize high bandwidth with wireless backhaul, a large number of base stations (BSs) are required along the railway. Therefore, this paper proposes the concept of optically backhauled moving network (OBMN) for local trains to efficiently provide backhaul links for local trains. In the OBMN, an autonomous BS (ABS) is set on the top of a train, and is connected to a gateway via optical backhaul. To follow the movement of the train, the length of optical fiber is adequately adjusted with a high-speed reel, which is located along the railway and spins to reel up and send out the fiber. When the train arrives at a transfer point, another ABS is set on the train and the demand is handovered to the newly set ABS. The number of required BSs and deployment cost will be drastically reduced with the proposed OBMN compared with the existing static deployment.