Moscow Metro, probably a biggest free Wi-Fi-network in the world
Today passengers of the Moscow Subway can't imagine their trip without a free Wi-Fi-network. The number of daily users of Wi-Fi in the Subway has exceeded 2.5 million users, up to 120 users have simultaneous access in each train carriage (each train have 6-8 carriages).
As of today, the Moscow Metro has 12 lines and 223 stations and its route length is 381 km (236 mi). The system has an average daily ridership of 6.73 million passengers with a peak of 9.28 million.
September 2013 one private company has provided free Wi-Fi access on 2 lines. Therefore the city authorities have opted for the creation of a wireless network in the subway.
The investments in the project amounted 56,25 million US dollars, with a seven years payback period. The provider doesn't open the sources of funding and underlines that the project was not involved by a government or municipal funds.
On the outer carriages, routers with antennas are mounted, it's slowly switched from one base station to another, which allows having the network with no gaps. Between outer carriages the cable laid along the entire train length, and each carriage has its own access point, combining into single "MosMetro_Free" network.
Each train car have 19,2 meters long; so a train has 154 meters maximum overall length. Two moving Routers at the outer cars are always located between two nearest static tunnel Access points. It provides constant no gap wireless network. Inside the train we have an Ethernet wired network, it provides the signal from two Routers to 8 Repeaters located in each car. Each Repeater provides up to 120 simultaneous WiFi connections with user devices on ~10 meters distance. So it's doesn't matter how many people in the cars, they have no interfere with tunnel network signal.
As of today, the Moscow Metro has 12 lines and 223 stations and its route length is 381 km (236 mi). The system has an average daily ridership of 6.73 million passengers with a peak of 9.28 million.
September 2013 one private company has provided free Wi-Fi access on 2 lines. Therefore the city authorities have opted for the creation of a wireless network in the subway.
The investments in the project amounted 56,25 million US dollars, with a seven years payback period. The provider doesn't open the sources of funding and underlines that the project was not involved by a government or municipal funds.
How does it work?
The most difficult part of the project was the creation of its own signal coverage technology. The provider design it by laying fiber-optic cables in subway tunnels. On each station is a server rack has been installed, from which the fiber-optic cables laid to base stations in the tunnel, located in distance of 450 m from each other. Parallel to the fiber optic cable the power cable is laid.On the outer carriages, routers with antennas are mounted, it's slowly switched from one base station to another, which allows having the network with no gaps. Between outer carriages the cable laid along the entire train length, and each carriage has its own access point, combining into single "MosMetro_Free" network.
Each train car have 19,2 meters long; so a train has 154 meters maximum overall length. Two moving Routers at the outer cars are always located between two nearest static tunnel Access points. It provides constant no gap wireless network. Inside the train we have an Ethernet wired network, it provides the signal from two Routers to 8 Repeaters located in each car. Each Repeater provides up to 120 simultaneous WiFi connections with user devices on ~10 meters distance. So it's doesn't matter how many people in the cars, they have no interfere with tunnel network signal.
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