The TD-LTE private network for Hefei Metro Line 2 has been completed as Anhui's first train-to-ground TD-LTE private network, indicating that the rail transit application in Anhui has been ushered into a new era. This exemplary case facilitates Caltta's development in wireless communications dedicated for rail transit.
Hefei Metro Line 2 was constructed along the Changjiang Road, including the Changjiang West Road, Changjiang Middle Road, and Changjiang East Road. Line 2 starts from the Nangang Station and ends at the Sanshibu Station along the Changjiang West Road, Changjiang Middle Road, and Changjiang East Road. With a length of about 27.76 km, Line 2 has a total of 24 underground stations. Line 2 passes six transfer stations so that passengers can easily transfer to other lines.
Hefei Metro Line 2 uses the type-B trainsets in six-car formations operating at a maximum speed of 80 km/h.
As a multi-service bearer system, the train-to-ground wireless network of Hefei Metro Line 2 provides the following services:
1. Passenger Information System (PIS) service
The PIS service includes the emergency text service and on-board live PIS service.
This system uses multicast technology based on shared channels to provide the live PIS service, greatly saving air interface resources.
2. On-board video surveillance (CCTV) service
The CCTV service uses on-board cameras for real-time video surveillance of the locomotive and carriages. This system allows video inspection of compartments to locate potential risks and take prevention and emergency response measures.
3. On-board security inspection service
4. On-board FAS information feedback service
Based on advanced LTE technologies and B-TrunC standards, Caltta's solutions provided a unified dedicated wireless communications platform to transmit PIS, CCTV video surveillance, and other service data and enabled a reliable QoS guarantee based on service priorities. This dedicated communications system, which was used on trains moving at a speed of up to 350 km/h, provided a variety of wireless coverage solutions in different scenarios and business models to ensure network stability and reliability.
The TD-LTE system architecture of this project is shown as follows:
Hefei Metro Line 2 uses Caltta's sophisticated train-to-ground wireless communications system dedicated for rail transit to carry a variety of services in the TD-LTE private network. To guarantee high reliability and stability of the services, Caltta has fully considered the system architecture and designed a complete set of solutions.
These solutions incorporated the PIS, CCTV video surveillance, on-board FAS information feedback, and on-board security inspection services in a transmission network, achieving efficient use of system and frequency resource. PIS video streams were transmitted by using the TD-LTE multicast technology, greatly saving wireless air interface and transmission bandwidth. In addition, business demand can be flexibly fulfilled in the logical transmission network.