Olympic train system keeps passengers in touch

Andrew and Siemens have jointly designed a wireless communications system for the CRH3 Harmony multiple unit trains, which were developed specifically for the Olympics and have maximum speeds of 350 km/h.

The trains began running on the Beijing–Tianjin high-speed railway line on 1 August, helping bring guests from all corners of the world to Beijing for the 2008 Summer Olympics.

Andrew installed and deployed MIR-T in-train repeaters in some compartments, which transmit and receive wireless signals to passenger handheld devices from existing base stations near the railways, providing passengers with high-quality and high-reliability mobile phone signals while they travel.

The company also conducted extensive on-site testing and radiofrequency measurements to confirm the system will meet passenger expectations. All those travelling the 120 km between Beijing and Tianjin can now pass the time on activities such as talking to friends or checking business email.

The dynamic gain control of  the train repeater series automatically adjusts the upstream and downstream gains, preventing excessive upstream noise from decreasing the reception sensitivity near the base station.

On high-speed trains, the upstream and downstream gains must be adjusted rapidly to maintain the relative stability of the wireless signals for passengers onboard.

The repeaters, which are mounted using a standard 19" cabinet, have low power consumption and wide feed voltages.