Shenzhen Subway Suffers Signal Interference Because it Uses 2.4GHz Public Wifi Channel


Concern is mounting over frequent incidents of train line signal interference on the Shenzhen subway system in southern China, caused by riders using portable wifi hotspots. Chinese business paper Caijing notes that two lines on the Shenzhen Metro Group network “employ communications based train control (CBTC) systems that transmit wireless data on the common 2.4GHz band, a free band open to the public and used by subway communications systems in most Chinese cities.”

The Shenzhen subway has 3G coverage, and the rise in popularity of wifi hotspot devices (for sharing out one 3G data source via wifi for multiple devices) is causing this potentially dangerous wifi interference.

Caijing also warns that China’s breakneck speed in building new metro systems in numerous cities is causing a lack of extensive testing of subway communication systems.