The Metropolitan Transportation Authority (MTA) has made a significant milestone in its multi-year effort to deploy a wireless network in the New York City subway system that combines DAS, Wi-Fi and 4.9-GHz public safety communications.
Thirty subway stations in Midtown Manhattan, including Times Square, Rockefeller Center, Lincoln Center and Columbus Circle are now online, in addition to the initial six in Chelsea, which went online in September 2011. Work on the first of seven phases was delayed by Superstorm Sandy.
“For the past three years, the MTA has been on a clearly defined mission to bring our mass transit system into the 21st century with upgrades to the station environment through several ambitious new-technology communications projects like this one, aimed at improving the travel experiences of our customers while offering another level of security,” said MTA Interim Executive Director Thomas Prendergast.
In a press conference, MTA officials joined with executives from Transit Wireless, Solid North America, AT&T, T-Mobile USA and Boingo Wireless to demonstrate the service April 25 at the Times Square Station.
Transit Wireless, owner, operator and prime integrator of the DAS network, plans to outfit the remaining 241 underground stations within four years and has already begun work on the next 40 stations, which include Grand Central Station, 34th St. Herald Square and Bryant Park in Midtown Manhattan, and stations throughout the Borough of Queens.
Solid’s DAS equipment was selected by Transit Wireless in 2012 for the project. Phase one is using a single head end located near Madison Square Garden, with fiber connectivity to each station. Rack configurations at the head end that connect to the signal source were performed by the manufacturer.
Building a wireless network for a transit system that ranks seventh largest in the world with 1.7 billion riders annually is a daunting task, according to Seth Buechley, president, Solid North America.
“It is like the Super Bowl but it’s not a one and done. It might be a little more daunting. It has to work every day with the metrics and the performance stats matching the SLAs [service level agreements] between Transit Wireless and their carrier partners,” Buechley told DAS Bulletin.
Solid deployed its Alliance multi-carrier product, which serves carriers and public safety, operating at 1 watt. “We were able to modify our Alliance platform to meet some of the unique requirements of Transit Wireless,” Buechley said. “We offered a beefed-up version of the product that was fully tested in our research and development facilities.” The system’s power may be increased to 5 watts in the future to provide coverage for the tunnels.
The subway system also required a wireless system that could be cooled using convection cooling only. The systems in a subway cannot use fans to cool the electronics because of the dust in the air. So Solid provided completely sealed units with cooling fins.
Going in side-by-side with the DAS system is an advertiser-supported Wi-Fi system, managed and operated by Boingo Wireless through an agreement with Transit Wireless. The Wi-Fi system shares Pctel antenna arrays with the DAS but not much else. The system uses Motorola access points (2.4 GHz and 5.8 GHz) and Alcatel-Lucent switches in each station, according to Nathan Cornish, Transit Wireless RF engineering manager.
“In the base station hotel there is a massive Cisco switching system that provides an interface between us and the Internet. In the [subway] station we typically have an average of up to seven Wi-Fi access points. Each one is connected to a central switch in the station via fiber optics. We have a one gig connection from the train station to the base station hotel, and inside the station we have a one gig connection to every access point,” Cornish told DAS Bulletin.
Laptopmag.com tested Boingo’s Wi-Fi service at the Times Square 42nd Street station and found download speeds of 21.9 Mbps and average upload speeds of 33.3 Mbps, while AT&T’s 4G LTE network averaged 20.4 Mbps and uploads averaging 8.9 Mbps.
Cornish reported numbers that were different. He reported LTE data speeds of 35 Mbps down and 15 Mbps up, with Wi-Fi coming in at 10-15 Mbps up and down.
Although many predict a rise in carrier-owned Wi-Fi, Buechley said that growth of combined DAS/Wi-Fi deployments comes in cycles. “Most carriers tell me that if they are deploying a DAS that is scaled for their needs, they don’t need to own the Wi-Fi offload,” Buechley said. Transit Wireless owns the MTA Wi-Fi system.