Tunnels are critical components of transport infrastructure and highly reliable and available radio coverage in tunnels is essential for tunnel management, mission critical (Tetra / GSM-Rail / signaling / track- to-train radio / PMR / DMR / AM / FM) and commercial (2G, 3G, 4G and future 5G) wireless services in various frequency bands. Especially in train and metro tunnels, leaky cables seem to be the only solution because of the masking effects of the trains.

So, leaky cable, which is the key factor to radio communication system in tunnel, how to monitoring and fast & accurate fault locating are critical issues to tunnel management, telecom operator, system owner or maintenance team, due to the difficulty in making repair works in the tunnel while the train is in operation.

Based upon Software Define Radio (SDR) technique, HELIOS^® DTFMS™ Radiating Cable Distance-to-Fault Measure System is a powerful leaky cable performance monitoring platform, it is designed to be easily integrated into existing or new radiating cable system in tunnel by compact size and low power consumption, and enable keeping precisely measures parameters of the leaky feeder such as VSWR, Return-Loss etc., and conduct real-time verification, monitoring and fault locating for the radiating cable system

HELIOS^® DTFMS™ Radiating Cable Distance-to-Fault Measure System mainly consists of four parts as below:

• DTFMS™ Fiber Converter Rack-mount Chassis (FCRMC): The DTFMS™ Fiber Converter Rack-mount Chassis is specially designed to accommodate optical converter for central power supply, saving space and power cables. Up to 16 slots Fiber Converter support
• DTFMS™ Rack-mount Switch: The DTFMS™ Rack-mount switch provide an easy way to collect all the Measure Node data by Console Unit
• DTFMS™ Console Unit (CU): Generally will be deployed on radio BTS room and be in charge to centrally monitor and manage all DTFMS™ Measure Node (MN) in network through fiber link, it will receive data (such as operation status of device, alarm message, operation performance of leaky cable, distance to fault, timestamp etc.) from MNs
• DTFMS™ Measure Node (MN): it will be connected to the leaky cable via a customized Combiner and it will keep monitoring and measuring the performance of leaky cable and regularly send measurement result and alarm message to CU via fiber link

The DTFMS utilizes an embedded WEB management system for system configuration and network monitoring. The embedded WEB management system collects key performance and alarm information from leaky cable and send back alarm information to Helios^® Network Monitoring System through fiber link (Cat 5e Cable) or directly integrated into customer's existing NMS through SNMP V2&V3 trap with a MIB file

Typical mounting options for the DTFMS include pole-mount and wall-mount. And the enclosure of the DTFMS is fully sealed IP-67 rated with compact design, which minimizes maintenance and is ideal for harsh environments