Home North AmericaNorth America 2012 Solving the latest broadband challenge: offering connectivity to trains, subways, and beyond

Solving the latest broadband challenge: offering connectivity to trains, subways, and beyond

by david.nunes
Cosimo Malesci Issue:North America 2012
Article no.:13
Topic:Solving the latest broadband challenge: offering connectivity to trains, subways, and beyond
Author:Cosimo Malesci
Title:VP Sales and Marketing
Organisation:Fluidmesh Networks LLC
PDF size:464KB

About author

Cosimo Malesci has been a forerunner in using wireless networks for security and industrial applications, providing new and cutting edge services. He holds both a bachelor and master degree in Ocean Engineering from MIT. After working in the marine engineering field, he co-founded Fluidmesh in late 2004 with offices in Boston, MA and Milan, Italy. This new venture has allowed him to apply his fine understanding of engineering to the wireless world. Fluidmesh has been a pioneer in the development of wireless technology by focusing on top-quality products for large areas at risk such as municipalities, industrial plants, seaports and marinas, archaeological sites, resorts, theme parks and racing tracks. In less than five years, Fluidmesh has positioned itself has a leading manufacturer in the market by focusing on thorough and practical solutions in a world increasingly preoccupied by connectivity and security matters

Article abstract

We all spend long time travelling – time that could be more enjoyable or more productive if access to broadband is made available. Currently 3G and Satellite provide connectivity while travelling, but the service is limited and fails in tunnels and subways. A new age WLAN is now available for the transport industry. A Train based WLAN is delivered via three mechanisms: Trackside nodes (backbone), Inter-Train (forward and backward cart based nodes) and the revolutionary Train-to-Ground which facilitates fast hand-off at high speeds. This fast WLAN is based on superior protocols that deliver fast hand-off and still enable large capacity. Costs of installing fast WLAN on trains can soon be recovered with the wealth of new services that they can open up, including remote management, surveillance and automatic control as well as consumers’ services.

Full Article

Like it or not, traveling is becoming a pervasive part of our lives. The amount of hours we spend on airplanes, trains, subways, and buses is increasing and is most likely not going to decrease in the near future. At the same time, our agendas are getting fuller and fuller and everyone is trying to be more efficient, more on time, more productive. Broadband connectivity is clearly one of the tools that has helped us to get there and do more in less time together with the Internet. Although in the past decade connectivity made great steps forward, we are still lacking reliable and high-speed broadband when we are traveling. However, things are about to change, as smarter wireless systems have been developed and are being deployed.

Trains and subways represent a very common means of transportation for many of us and have, at the moment, a major broadband connectivity issue. In both scenarios, the most common solution that is currently offered is based on 3G. So if you have a Smartphone, you are most likely going to stick to your wireless carrier and use it as your gateway to the Internet while on the road. Alternatively, a certain number of high-speed trains now offer Wi-Fi connectivity. Although this sounds like a great idea, it usually ends up offering a service that is worse than the one you get on your Smartphone.

The reason is that most trains provide Wi-Fi using a 3G backbone. A 3G Modem or a combination of 3G Modems from different providers connect to the backbone and then broadcast connectivity to passengers by using a series of Wi-Fi Access Points mounted on each cart. Overall, you have the same limitations of your Smartphone in terms of connectivity and performances. In most rural areas, you will be limited in bandwidth or have no service at all, you will be limited to few megabits of throughput at the most, and you will be required to download all your large files when you get back at the office. In addition, most of the time the on-board Access Point gets overwhelmed by too many people trying to connect to them, leaving you with little hope to download that major presentation you wanted to work on.

Were you thinking of streaming the latest episode of Man vs. Wild? Forget it. Doing a conference call with your kids on Skype? Nope. And how about downloading that GoToMeeting Webinar you didn’t have a chance to attend last week? Not possible. You will be stuck with your emails on the condition that they don’t have any large attachments. In addition, 3G-based solutions are expensive to maintain as the monthly subscription and usage charging add up pretty quickly without any guarantee about the quality of the service provided by the carriers.

A solution that has been deployed successfully as an alternative to 3G is satellite connectivity. The backhaul is created by a sophisticated tracking antenna mounted on the roof of the train. The advantage is that it is twice as fast as 3G in terms of throughput available and that it doesn’t require any roaming, making it a very reliable solution for vehicles travelling faster than 100 mph. The downside is cost: both installation cost and service charges make it the most expensive solution out there, limiting its success. In addition, it requires clear line of sight with the satellites, so it will not work in tunnels, another major limitation of this technology.

WLAN is offering a viable alternative to 3G and Satellite and it is on the rise in the transportation market as the solution that offers the best trade off in terms of cost and reliability. This WLAN solution uses unlicensed bands in the 2.4 GHz and 5.1 to 5.8 GHz space and can offer up to 100 Mbps of usable throughput over few miles of distance.

For mobility applications on trains and subways, the WLAN system can be divided in three parts: the Trackside Network, the Intra-Train Network, and the Train-to-Ground Network. The Trackside Network is the backbone of the infrastructure and is usually composed by numerous trackside cabinets, each with a wireless node that will then be used for Train-to-Ground communication. Each trackside wireless node is then connected to a fiber or wireless backbone, depending on the environment back to the main network router.

Then there is the Intra-Train Network which is the equivalent of the Track-side Network but between train carts: it allows the sending of data back and forth between train carts. This is built by a series of WLAN nodes, usually two per cart, pointing forward and backwards along the direction of traveling. This network has a dual purpose: it is able to create a connection between train carts as well as provide the connectivity with the track-side nodes. Just as a side note to underline the effectiveness of wireless solutions, WLAN has provided such an effective connection for intra-train communication that it has been also used to replace many wired couplers that were used for intra-train communication in the past. The main reason for this change is the fact that wired couplers tend to wear out due to the motion of the carriages. They also have a fixed bandwidth and limited data rate which place severe constraints on the upgradeability of an intra-train network.

Where WLAN technology truly shines is in the Train-to-Ground network which is the most revolutionary piece of the network. Traditional WLAN solutions have had limited use in mobile applications in the past due to their hands-off time in high-speed roaming. For example, an off-the-shelf 802.11 solution provides an average hands-off time of 700 ms. Although this might work for some semi-mobile applications, it will not be reliable when used at high speeds such as on trains, subways or buses. Through new routing algorithms and more powerful hardware, the performance of WLAN solutions has significantly increased and can now offer hands-off times of less than 2 ms and can cope with fast roaming up to 150 mph, yet still transfer up to 100 Mbps of usable throughput. This new technology, if implemented correctly, opens up a whole new world of features and entertainment to customers and train personnel alike, which would help recover the cost of setting up the WLAN infrastructure and generate an additional revenue stream for transportation authorities.

Moreover, with so much bandwidth available, the same network could be used to increase the safety on board by having live video surveillance monitoring as well as Automatic Train Operations (ATO) through CBTC (Communications Based Train Control). ATO, for example, coordinates trains to increase service efficiency and frequency and maximize track utilization using a central control. In order to do this, a large amount of data including train and passenger status, video-surveillance and emergency controls needs to travel back and forth between the train and the central control, which is beyond the capabilities of the radio technology currently in use on trains.

WLAN offers a few more advantages over 3G and satellite communication, such as flexibility and reliability. For example, in a tunnel where both 3G and satellite fail, WLAN can be deployed as the Train-to-Ground communication and can operate also in few feet of space. In addition, in case the track goes through sharp twists and turns, increasing the density of the trackside wireless nodes will ensure continued wireless coverage in the environment. WLAN solutions also work well in congested environments such as urban areas, thanks to a number of strategies to offer reliable connectivity in these conditions, such as the use of highly directional 2×2 MIMO antennas as well as narrow RF channels.

If you look at the cost of installing a WLAN solution for Train-to-Ground communication, things look promising. The cost of the hardware has been decreasing substantially in recent years passing the US$1,000 per node threshold. In addition, given the good penetration of WLAN, you would need a wireless node every half-mile on average. This brings the cost of the turn-key solution within reach of many transportation authorities and could be recovered in two to five years, due to the many services that can be provided on top of the network.

Getting out of the train and subway space, the same concept can be applied to many other vehicles including buses, trucks, passenger ferries, and possibly even airplanes opening up a world of new opportunities and extending the limits of WLAN technologies to well beyond what was considered possible just a few years ago.


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