To the American eye, double-decker vehicles are quaint -- even a tourist attraction. But to British freight company Pallet-Track, the double-decker trucks that roll within its warehouse walls are nothing more than moving solid masses, seemingly designed to absorb wireless signal.
Yet these trucks were only one of Pallet-Track's concerns when it came to implementing a new wireless LAN (WLAN).
More pressing was the company's rapid physical growth and growing RF tracking system. Last October, Pallet-Track moved from a 120,000-square-foot facility that could process hundreds of overnight packages daily to a 267,000-square-foot warehouse that processes about 5,000 pallets a day.
"One of our benefits is our IT. We provide transparency so we can track and trace all pallets from the customer through the hub and into every delivery destination," said Chris Comerford, corporate sales manager for Pallet-Track.
Pallet-Track had been providing that transparency with barcodes and Motorola RF scanners. The data ran on a small Cisco Systems 802.11b WLAN.
But in the new warehouse, that tracking proved to be trickier. First of all, in the old building, trucks remained outside and packages were brought inside to be scanned and then returned to vehicles. In the new setting, trucks packed with pallets roll in and out all day long, potentially blocking wireless signals. The company needed an innovative WLAN design that would work around these moving obstacles.
What's more, running an RF system with the ability to track between 5,000 and 10,000 pallets through a multi-stage process every day meant that the WLAN had to handle massive amounts of dynamically changing dataflow at all times.
"In the old warehouse, we had wireless access points, but it was on a much smaller scale and it took a lot longer to scan everything," said Mac Babb, Pallet-Track's IT manager.
So when the company moved warehouses, Babb turned to integrator Worldwide Solutions for a new strategy.
"The warehouse itself has very high ceiling spaces, steel cut walls, thick concrete walls into the office space, and an RF footprint throughout," said Simon Burgess, technical manager for Worldwide Solutions.
The Cisco network installed in the old building wouldn't have been sufficient in the new space even if more access points were added to the mix, Burgess said, adding that an entirely new system was warranted.
Since Worldwide was a Trapeze Networks partner, Burgess pushed for a change in technology brand. He also promised that Trapeze equipment would cost about 30% less than equipment from Cisco and other competitors.
When Pallet-Track agreed, Worldwide first set out to deal with the trucks.
"We couldn't have [equipment] in any space where it could get hit [by the double-decker buses]," Burgess said.
In all, Worldwide implemented 14 Trapeze 802.11g MP422a dual radio mobility points in the warehouse and another two in the offices. The APs were placed above the height of the trucks; but then came the issue of signal control. Worldwide addressed the signaling problem with creative antenna design.
"The way the APs and antennas are formed, they are designed to spread the signal horizontally," Burgess said, adding that other systems send signals vertically, which would have been useless in this scenario. "[In other systems] you have to imagine an AP meeting a signal in a spherical pattern. Here, instead of the sphere, you have a donut-shaped pattern that spread the signal out wider."
The 'g' technology was used specifically to support the Motorola scanners.
Burgess also pointed to Trapeze's "lightweight controller architecture," the MX200r mobility exchange controller, which he described as "one piece of tin looking after all of the APs." He said Pallet-Track was impressed that each AP was individually managed by the controller.
Ahmet Tuncay, Trapeze's chief technology officer, said it was the RingMaster management suite that made the AP layout possible. RingMaster can import three-dimensional models of buildings and consider RF characteristics for various types of building structures to determine how many APs are needed and where they should be installed.
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