Subway Transit Tunnel Cell Phone Signal Service Booster Installation Service

Subway Tunnel Cell Phone Signal Service Booster Installation.

Whether cellular, wi-fi or public safety radio signal reception improvement, SignalBooster.com has capability to enhance all types of wireless signals in transit systems.

Boston Subway.

One of the oldest subway systems in the US is in Boston, with tunnels and stations that have been used continuously for longer than a hundred years. The Massachusetts Bay Transportation Authority (MBTA) made a decision in 2005 to provide Boston subway riders with continuous cell phone coverage from end to end. This wireless network makes connectivity available to more than 20 miles of underwater and underground tunnels, and 40 stations. The network provides signal past flood-gates, into stations that are at least a century old and through curving tunnels.

The project was implemented in 5 phases over a 10 year period, and consisted of 4 phases:

Phase 1: Analysis. In this phase, the technical team walked the complete length of tunnels during nighttime while trains were not operating. The layout was studied and mapped, and any obstructions that could potentially block signals identified, including big conduits and pipes that cross the tunnel or run along the walls. This design had to cater for infrastructure in platforms and tunnels that are decades old. Trains nearly fill the MBTA tunnels completely, unlike new subways with more clearances, allowing for minimal space where radio signal can propagate or where antennas and cable could be installed.

Phase 2: Gathering Signal Data and Testing. RF signals from outside antennas are able to penetrate into platforms and tunnels in different degrees. Some of the track runs above ground, and the signal from cell towers in those areas are strong enough to supply commuters with wireless service. To evaluate signal strengths all over the system, the technical team measured pre-existing signals in stations and on trains to determine how strong the signals were. This was done as signal booster systems work by picking up where outdoor signals attenuate. Test antennas were installed and the team took train trips with dedicated test equipment to record actual signal levels. By doing a detailed empirical study of RF signal strength throughout the subway system, the technical team was able to identify the exact locations where remote antennas and amplifiers had to be placed.

Phase 3: Design. A multi-disciplined team collaborated on the various aspects of fiber optic DAS distribution and RF system design. To solve the problem of difficult installation areas and challenges presented by longer curves, the team recommended using radio frequency systems' radiating cable rather than antennas. Radiating cable is normal antenna cable, but slots in the outer conductor allows it to work like a sprinkler system, "spraying" low signal levels along the entire length. Jumper cables in cable sleeves were used at the flood-gates close to South Station. These cables connected sections of radiating cable to provide wireless service continuously, while at the same time keeping these clear of the flood-gates should they have to be used in future.

DAS equipment was selected from several vendors at varying times during the initial phase, depending on how equipment evolved over time. The DAS solution implemented requires a single fiber to support up to 8 remote units. The design is also modular to make it easy to upgrade as new frequencies are added by carriers.

Phase 4: Buildout. Wireless network expansion took place in 5 construction of from 2007 to 2015. By 2015, commuters were able to use wireless services anywhere on the Boston subway. Included in the network are 454 DAS antennas, 107 remote equipment locations, 82,535 ft. of radiating cable, 642 remote amplifiers and more than 21 miles of fiber optic cable.

Currently, 5 carriers use the system to provide their subscribers with service. The MBTA wireless network is one of only a few systems in America with a neutral host. It provides commuters with coverage right through the underground tunnels and platforms, enabling them to use uninterrupted service everywhere. As passenger service start daily at 5 am and continues until 1 am, there was a small window of 2 hours per night during which tunnels were not used and wireless equipment could be installed safely.

Lincoln Tunnel.

The Lincoln Tunnel connects Manhattan to New Jersey. At any given point along its 1.5-mile length, a train is submerged about 100 feet below the Hudson River and enclosed by rings of iron that weigh 21 tons. To get wireless signal into this environment was challenging to say the least, but it was done.

As with the Boston subway, there was not enough space in the tunnels to install equipment. The solution was to use radiating cable, also known as leaky coax.

Although the implementation process used in the Lincoln tunnel was essentially the same as that of the Boston subway project, there are minor differences. While the work in Boston was carried out at night while no trains were running, the Lincoln tunnel experienced a lengthy series of overnight tunnel closures. The system is broken up into four quadrants within the tunnel itself. While the wireless network in Boston is carrier agnostic, the Lincoln tunnel project was executed by AT&T some 20 years ago.

NYC.

The New York City underground subway stations received their cellular coverage much later than the other two subways mentioned and the work was only completed last year. All active stations have service from AT&T, T-Mobile, Sprint and Verizon, together with WiFi, which went live shortly before that.

Toronto.

All TTC subway stations are equipped for cellphone service, enabling commuters to text and chat while waiting for the next train. Although the TTC hails this as a milestone, and expects the travel experience of millions of customers to be improved significantly, Canada's three major cell service providers have not yet joined the project. This unfortunately means that currently, most commuters will not be able to use the underground cell network.

Installation of cellular connectivity infrastructure has been completed at all of Toronto's 75 subway stops, including the 6 new stations on the Yonge-University-Spadina line extension recently opened.

Tips for a Successful Wireless Network Underground.

SignalBooster.com has done many massive wireless network installations of this size and scope, and over the years we have learned what works best:

1. Design for numerous carriers and be a strong referee. We cannot stress this point enough and it did not land on the list at number 1 accidentally. As multiple mobile carriers are used in virtually all markets, the transit authorities' goal is wireless connectivity for as many of its customers as possible. This means that for the project to be truly successful, multiple carriers need to sign up, including AT&T, T-Mobile, Sprint and Verizon. A strong referee (neutral host) really simplifies the complexities by working with carriers directly when they add services to this network and will also handle all logistics, technical and otherwise, for establishing network connections. If this is not done, the transit could end up as Toronto did, spending a massive amount of money without giving all their customers the full benefit.

2. End-to-end wireless service. In today's connected world, people use mobile phones all the time and everywhere, and expect to be connected to the carrier's wireless network continuously. Poor call quality and dropped connections between stations will lead to customer complaints and frustration. When SignalBooster.com designs a network, we plan for end-to-end service above ground, through tunnels and on platforms. Although this could be a massive challenge in subways that have 24-hour service, the network can be extended through tunnels in many cities during hours that the trains don't run.

3. Hostile environment. Subways are one of the most hostile environments for electronic equipment. All components of the system, including DAS equipment, fiber enclosures and cabling must be designed to endure extreme temperature variations, ambient brake dust, moisture and vibrations from passing trains, year in, year out, 24x7, without any special maintenance. Equipment to be used in these extreme conditions needs to be selected carefully and only be of the highest possible quality.

4. The head end must be above ground. Tunnels and stations have extremely limited space, as well as limited access and safety concerns. These factors make it logical, if not mandatory to locate the head-end, where carriers make their connections to the wireless network, at a location above ground that offers both unfettered access for carrier personnel and direct connection to the subway.

5. Future-proofing. With subway installations, a "good enough" approach to capacity is never good enough. The network will inevitably experience traffic that keeps on increasing from commuters as they browse the Internet, call friends, watch videos and use social media. From the start of the project, think ahead to support all spectrum and all carriers. Many subway networks are currently designed for 4G, but should have been planned to cater for 5G, with greater demands from an ever increasing number of commuters, and higher frequencies.

How We Can Help.

In conclusion, whether you’re working on improving cellular and public safety bands (including FirstNET) reception in a long underground tunnel or a long stretch above ground but under a mountain - We have the expertise to select the most suitable equipment and install it in a manner that provides good service perpetually. Submit your details for a transit tunnel signal booster installation quote, today.