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Bridging the Arctic with GSM-R Solution

9/04/2013 9:23:00 AM

Background

The Hada High-Speed Railway (HHSR) is the world’s first above the Arctic Circle. It connects Harbin, China’s Heilongjiang province and Dalian in Liaoning province. Trains travel 572 miles (921 km) through rugged terrain at speeds up to 217 mph (350 km/h).

HHSR chose Huawei, which controls more than 48% of the Chinese railway communications market, to provide a field-proven GSM-R solution similar to ones provided for several other high-speed railways.

Challenges

HHSR chose Chinese Train Control System Level 3 (CTCS L3) specifications — CTCS L3 is the equivalent of European Train Control System Level 2 (ETCS L2) — and GSM-R technologies for communications between trains and stations. To be successful, the project had to overcome several serious challenges.

Extreme weather

China’s northeast region is cold, with long winters and temperatures as low as -40ºF (-40ºC). The extreme cold requires devices specially designed for the tough conditions.

High-speed coverage

Communications between stations and trains traveling at such high speeds present unique challenges to wireless stability and quality due to Doppler frequency shift and trains running through tunnels.

Limited number of frequencies

Radio frequency choices were limited, making planning and design to avoid poor quality and signal interruptions difficult.

Solution

Huawei provided an end-to-end GSM-R solution already used on several other high-speed passenger and freight lines.

Hot Standby (HSB) disaster recovery

The solution provides features and algorithms specifically designed for high-speed railways to ensure service continuity and hot backup for all network elements and core networks using:   

  • The core network provides real time HSB based on Mobile Switching Center (MSC), dual homing, and Mini-A-Flex technology
  • The access network is equipped with a Base Transceiver Station (BTS) ring network, carrier frequency redundancy backup, and wireless redundancy carrier technology
  • Automatic Frequency Control (AFC) and fast switching algorithms ensure continuity

High-speed cell coverage

To simplify frequency design and reduce cell hand-offs, Huawei provided modular DBS3900 Distributed Base Stations (DBS) with multi-site technology and Remote Radio Units (RRU) that combine multiple cells from different physical addresses into one site with a single logical cell. They also:

  • Reduce the number of repeaters, lowering costs and speeding construction
  • Expand cell coverage
  • Offer greater capacity
  • Ensure smooth network switching
  • Provide security for train control signals
  • Operate at extreme temperatures as low as -40ºF (-40ºC)

Interoperability

Huawei and signal system provider Bombardier completed a series of Interoperability Tests (IOT) to ensure full device and system interoperability.

Benefits

  • Increased reliability in extreme weather conditions
  • Reduced maintenance and spare parts costs
  • Extended cell coverage and increased capacity
  • Better signal security
  • Fully tested device and system interoperability