Transit Wireless, the company that is installing wireless network infrastructure throughout the New York City subway system, said it believes it has come up with a way to better serve the customers of AT&T (NYSE: T), Verizon (NYSE: VZ), T-Mobile US (NYSE:TMUS) and Sprint (NYSE: S) when they catch their trains.
As Nathan Cornish, director of RF engineering at Transit Wireless, describes it, the subway is like a coffin. That's good for wireless communications in the sense there's no interference from macro cells, but there's also no coverage. That means distributing antennas throughout the entire station -- and accommodating all the technologies, from GSM to LTE, that carriers are using.
The stairwells serve as the handing-off place, designed to provide enough coverage so that the above-ground macro cells can hand off into the below-ground system. "There's no point having a system underground if you can't make a call and walk in and out of the subway without dropping, so that's a very big challenge," Cornish told FierceWirelessTech.
Of course, the first major challenge in any subway deployment is the fact that it's underground, but it's actually considered an above-ground deployment in the sense that all the equipment has to be able to withstand elements like water; maintenance workers routinely hose down the stations to keep them clean. Add to that the fact that this subway runs 24 hours a day, seven days a week, and you see how the environment is more than a little challenging.
Last week, Transit celebrated the completion of Phase 4 of the deployment, which added 37 stations to the network, including some marquee stations in the upper Manhattan and Bronx areas. The tally of currently live stations is 146.
In the long-running project, Transit Wireless is bringing cellular and Wi-Fi service to underground Metropolitan Transportation Authority (MTA) subway stations in New York City. Work is expected to be completed in 2017.
"This is an extremely complicated and complex environment in which to enable cellular or wireless connectivity and at this point, I would peg it as one of the world's largest DAS networks," said Mike Collado, vice president of marketing at SOLiD, which is supplying the DAS technology for the network.
"The RF signal is actually superior below ground compared to above ground because literally, you have no interference with the macro network so you get a really great performance and clarity with the signal underground," he said.
It's not just about coverage. In subway stations, passengers congregate on a platform for a certain amount of time and then they leave, so the network needs to be capable of handling those spikes. "You've got to engineer the system in such a way that it can meet the ebb and flow of capacity requirements as well as coverage," Collado said. Plus, the New York City subway was not designed with cellular in mind, so that means there's not a lot of space to put equipment.
That's where the base station hotels come in. Transit Wireless set up five of them in centralized locations around New York where the operators' high-dollar, large-sized equipment is located and protected. The advantage for the carriers is they don't need to send their technicians anywhere near the subway stations.
While base station hoteling isn't new, Collado said Transit's build is informing how other work gets done, including how large carrier equipment is housed and moved from what he calls high-rent districts to lower-rent districts where rents are more affordable. "This model is being adopted in other sectors," he added.
The wireless carriers contribute capital and ongoing fees for the New York transit system but the system, from an up-front build standpoint, is funded by Transit Wireless. The next phase is already under construction and involves another 37 stations, 31 of which are in downtown Manhattan and others are in Brooklyn. Phases 6 and 7 will cover the remaining 87 Brooklyn stations and a few stations scattered throughout.
By this time, Transit and SOLiD aren't running into too many surprises. "This is a very well-oiled machine at this point," Collado said.
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