Articles

Wireless Crossing

The Washington State Ferries system is testing a way to provide wireless Internet access from the dock to the ship and over the water.

by / January 20, 2005
Serving more than eight counties in Washington state and the province of British Columbia, Canada, the Washington State Ferries (WSF) system includes 10 routes and 20 terminals served by 29 vessels.

To improve the ride for the more than 75,000 Puget Sound residents commuting to work or school via ferries during the week, the WSF worked with Mobilisa and Chantry Networks to implement and test the Wireless Over Water (WOW) system, said Jim Long, director of information technology for the WSF.

"Our riders are, for lack of a better term, basically captive -- at least while they're on the vessel," he said. "Many of our passengers arrive 20 to 30 minutes before the vessel sails. On our San Juan Islands route, our international route, some people arrive two hours early, so this would be a way for them to surf the Web and do their e-mails."

In the Central Sound, Long said some vessels transport 2,600 people, many of whom are professionals, and wireless access would help them with productivity during their commute. Many professionals also live in the West Sound and commute to Seattle.

"In their cases, some are billable hours, so they can extend their hours -- I say they can make partner faster -- things like that," Long said. "Or people like me, running an IT department here, I can take my laptop home with me, and on the boat I can deal with the administrative e-mails -- the ones I never get to."

The wireless network has gone live on the M/V Klickitat, which serves the Port Townsend to Keystone route. The network will eventually be installed on three major ferry routes and is expected to serve 300 to 400 simultaneous users.


Nest Egg
U.S. Senator Patty Murray, D-Wash., and Mobilisa helped the WSF secure an $800,000 research and development grant. Murray serves as the highest-ranking Democrat (and is the former chair) of the Senate transportation appropriations subcommittee.

Long said the grant contains two main provisos: First, the wireless network must maintain continuous connectivity shore-to-shore. Second, it must improve the ridership experience.

"In that little egg are things like performance, being able to prioritize, types of traffic, limiting 'hogs,' if you will -- people who try to download a 300 MB file while other people are trying to answer a 20-byte e-mail," Long said.

"If all this comes together and works, which it will -- which it does -- then we float an RFP out to the private sector to outfit all of our vessels, all of our terminals, all of our decks."

Long said a private company will run the service, and the WSF would collect a royalty, similar to how onboard food concessions are handled.


Sign Me Up
The WSF wants to offer a wireless experience ubiquitous to the user to eliminate worries about which wireless ISP to subscribe to.

WOW users can log on to the network so long as their PDA or laptop is outfitted with a wireless card or antenna, and they have an account with a third-party provider, such as AT&T, Verizon or T-Mobile, Long said. Subscriptions to such services are readily available and typically can be paid for on a per-day or per-month basis.

"Cost is totally independent of the infrastructure," said Luc Roy, Chantry Networks' senior director of product management. "Mobilisa can create a unique service set identifier [SSID] for every service provider -- T-Mobile, AT&T Wireless, Verizon.

"It also has unique administrative domains for each of these SSIDs," he continued. "We can actually work with T-Mobile's Web site where, if you were a wired user, you just enter your name and password; and if you don't [have an account], you can sign up for one."

Actual cost also boils down to the ISPs and the payment method the person chooses, Long said.

"If they choose a monthly thing, maybe it's $19 a month; if they choose a daily thing, maybe it's $3 a day or $5 a day," he said. "That's really up to the private sector to provide."

An online customer survey received 2,000 responses, Long said, and other than those who said it should be free or who would pay quite a lot, most responses indicated a willingness to pay between $19 and $39 for monthly service.


How It's Done
There were two primary challenges, Long said -- the distance the signals would have to travel over water and maintaining signal connectivity.

The system uses 802.11 radios from Proxim, and BeaconWorks routers and BeaconPoint access points from Chantry Networks, which partnered with Mobilisa and improved its software to perform a dynamic handoff from one signal to another, Long said.

Imagine two overlapping circles radiating out over the water from two shore positions. A vessel on a route to a port moves between those circles as it chugs across the overlapping area.

"As the vessel goes across, it's talking to A," Long said. "As it goes across [the overlapping area], it's talking to A and B, and then it's talking to just B. It's been a challenge, but it works. The one that had a stronger signal -- so shore position A and shore position B -- could do [the handoff] in a matter of milliseconds versus a matter of minutes.

"That's what gives the semblance of continuous connectivity."

Through tuning and proper antenna selection, Long said Mobilisa has essentially gone seven to eight miles out in one direction over water. On another project for the Navy, he said, the signal has been sent out 13 to 20 miles over water.

"The Navy's got more money than we've got," he said. "But other than our international run, which is from Anacortes [in the San Juan Islands] to Sidney [on Vancouver Island, British Columbia], there is no single run longer than 12 miles. So if you go seven and seven, you've got it covered."

Long also said each antenna on shore directly connects to the Internet, meaning the load of wireless users is split between them. "Virtually every run is two vessels, so vessels A and B cross in the middle of the sound, so both terminals are always live."


The Nitty-Gritty
Thanks to the WOW network, people with a regular Wi-Fi card can walk around on the ferry and be connected to the Internet, said Mobilisa CEO Nelson Ludlow.

"There are two parts to the technology," he said. "One is the shore to boat -- the ship is moving, so our shore system connects to a moving boat. Once we capture that signal on the boat, we redistribute it on the boat using Wi-Fi."

Getting Wi-Fi to work on runs as long as almost 20 miles was a challenge, especially when compared with a Wi-Fi setup at home that works for just a few hundred feet, Ludlow said.

"In this case, we had to get it to go out dozens of miles. To do that, we used some of our technology called Wireless Over Water. WOW includes keeping a constant connection to a bunch of focused antennas all the way out to a moving ferry," Ludlow continued. "The other big deal about wireless -- and this is important to a layman, but I don't think a layman understands it -- is that roaming is not part of the typical Wi-Fi environment."

Wi-Fi is fine for sitting in a coffeehouse or at home, but when trying to roam between different access points -- as one would do driving in a car with a cell phone and using different cellular systems -- users expect to switch seamlessly between the different systems and stay connected.

To achieve that level of connectivity with Wi-Fi, the WOW network uses two technologies. One is advanced switching algorithms from Mobilisa so the ship stays connected during the trip's duration. The other is from Chantry, and it allows users to seamlessly roam from one terminal to the other.

"A person could literally park in the parking lot, get connected, drive onto the ferry, use the system the whole time the ship is moving, and even drive off onto the dock on the other side and still stay connected," Ludlow said. "That's a big deal in Wi-Fi."

Chantry's Roy describes the technology as consisting of different layers -- the infrastructure layer that allows communication from a boat back to the main shore, and the communications layer that offers the service to the client.

"We basically allow you to manage different administrative demands, for example, one could be for T-Mobile where Mobilisa would wholesale T-Mobile's services," he said. "We would create a different logical network for AT&T Wireless, who then can offer their own wholesale service on top of Mobilisa's infrastructure."

Chantry Networks handles all remote management and segregation of users, all policies for users and all administrative domains. Mobilisa works with a wireless ISP to offer the ISP a place from which to send their signals.


Proof of Concept
Any problems, issues, opportunities or challenges to the WOW network would arise in the Port Townsend to Keystone route, Long said, which is why the area was perfect for a proof of concept test.

"It gave us the chance to test the two distinct frequency ranges -- 802.11b and 802.11g -- and we went with 802.11g for the backhaul," he said. "The real problem is the backhaul, getting it from the vessel to shore, because that's the part that's open. But on the vessel, your laptop can be 802.11a, b or g."

Because of shipping in the region, the ferryboat's path has an "s" curve. The route also crosses the shipping channel, which is regularly traveled by nuclear submarines, aircraft carriers and ocean-going vessels. Ferries must yield right of way to larger ships.

"You don't want to run into an aircraft carrier, so [the ferry's] path changes even more," Long said. "It's not like a railroad track going point A to point B all the time -- it's all over. And then with tides and currents, that can also make the route change."

To resolve the "s" curve situation, multiple shore stations were installed, so this route has four shore stations versus two like the other runs. Big vessels are also blockage points if they get in the way of the antenna to the shore, so it's important to reacquire the signal as rapidly as possible.

Fog on the Port Townsend and Keystone route is another problem.

"High-bandwidth wireless is wonderful ... except when you have a lot of moisture in the air," Long said. "We had a wonderful success up in Port Townsend, and now we're outfitting a couple larger vessels to get a better feel for the customer experience where we have a lot of users trying to access it."

Despite the WOW network's success, Long said the No. 1 priority is to keep the boats moving.

"Anything that precludes the boat from moving takes priority over throwing in a wireless system," he said.


What's Next?
A sister wireless system that will handle WSF network traffic is in the works, Long said, explaining that the WSF system will run ship maintenance off the vessels and many other technology applications that are shore/server-based.

That flow of information must be treated differently.

"We do not want to commingle customer Internet use, which is basically uncontrolled," he said, adding that the system will be 802.11i. "Given some of the things going on with homeland security, we'll have cameras on board we'll be monitoring, so we need a dedicated pipe."

Long also said incorporating wireless into WSF vessels will most likely generate more revenue for concessionaires. Food can be purchased aboard most vessels, and the WSF is working to get food services on all of its boats.

"If vendors could take a credit card and get it authorized, they know their sales would rise," he said. "The one vendor we currently have, they're going to have wine tastings with premium Washington wines. We'll get 'boutiquey' kind of stuff on board -- kiosks."

There may also be cell phone possibilities on a pay-per-use basis aboard the vessels.

"Believe it or not, a lot of people don't have cell phones," Long said. "We are always looking for new ways to generate revenue where we end up being the landlord, if you will, and not the provider."

Under these sorts of partnerships, the WSF provides floor space, electricity, lights and whatever else is necessary; the vendors run their for-profit businesses, and the WSF gets a royalty.

"We really think this is a good, viable project," Long said. "We had the Small Business Administration here -- they're touting the project as a major success for small business dealing with a state agency, which isn't the easiest thing in the world."
Jessica Jones Managing Editor