Case Study: Blending Wi-Fi and Bluetooth for a tracking system
Right tech for the right job.
Last month, delivery company UPS leapt to the forefront of wireless users, with a plan to equip 55,000 of its staff with wearable devices for both Wi-Fi and Bluetooth. The devices will be used to scan barcode labels on packages continually, and pass information to a tracking system which UPS' customers can use on the Web.
It's one of the most ambitious enterprise wireless installations we know of, and one where technologies have been selected carefully according to their strengths and the way they match requirements - leading the company to mix two wireless technologies, Bluetooth and Wi-Fi.
However, it gives little comfort to the vendors pushing Wi-Fi for office systems, as UPS has no plans to use wireless LANs for office work. It is also a blow to RFID systems currently being promoted for tracking objects.
"Barcodes aren't broken, so why should we replace them?" said Graham Nugent, European strategic IS manager at UPS. Currently RFID tags are too expensive to use on UPS' packages, he says, and clearly does not expect that situation to change before this huge roll-out is finished (not till 2006). "If RFID tags cost less than a cent, then we would be interested."
UPS is not ignorant of RFID. "We have an RFID pilot, and we are sitting on a couple of international standards bodies," he says. The company wants to make sure that when RFID is more widespread, the standards behind it are truly global. This is not so much for UPS' own scanners - as a global company it could make sure it had the same scanners in every sorting office, but to allow RFID tags to be readable by third parties, say by airport baggage handlers.
At its annual Technology Summit, in Germany last month, UPS presented a likely cost-curve for RFID which suggested tags would still cost about five cents in 2006, cheap enough for "postal services" to appear on the list of applications, but not yet cheap enough for UPS to roll out RFID.
What does the system do?
UPS wants to scan its parcels every single step of their journey and to make those scans quick and cheap. "It will allow our staff to scan sixty packages a minute," says Nugent.
The staff at UPS' hubs and package centres will all wear scanner rings which have a barcode reader and a Bluetooth connection. "Actually, it's more of a knuckle duster," says Nugent, as the scanner goes over two fingers. Specially designed in partnership with Symbol, the system is developed from existing wearable scanners , which have a wired connection.
A wireless scanner ring is safer, as the wires can snag and cause injury, explains Nugent. A wireless system is also more robust, so the company expects to save money on spares and repairs. Specifically, UPS expects a 30 percent reduction in equipment and repair costs, as well as a 35 percent reduction in downtime and a 35 percent reduction in the amount of spare equipment needed.
The scanner connects by Bluetooth, to give the right range and battery life (more detail on Bluetooth), linking to a PDA-like device worn on the belt. This then links on to an 802.11b Wi-Fi network in the building, to transmit the data, to the tracking system. Wi-Fi was chosen for its range and the fact that the WLAN has to be shared by many users with scanner rings (Wi-Fi, Bluetooth and GPRS compared).
The belt-mounted device, again, is purpose built. It runs Windows CE, and supports some local applications, but does not have a colour screen or other PDA functions. Obviously, it supports both Bluetooth and Wi-Fi, and this caused some development issues.
"Wi-Fi and Bluetooth share the same band," says Nugent. Early fears that the two would conflict have been largely satisfied, but UPS found that in this dense wireless environment it had to work to make sure the two did not snarl each other up.
"We worked with the IEEE and came up with an implementation," says Nugent. "We had to experiment with how often Bluetooth can send." In the end, it turned out that - despite the higher bandwidth of Wi-Fi - the PDA should spend 80 percent of its time talking to 802.11b, and only 20 percent talking Bluetooth.
In consultation with the eventual users, UPS had a visible signal put into the device to show a successful scan. Most scanners bleep, but this sound can be lost in a noisy warehouse, causing the user to rescan the label. That's not much of an issue with a wired scanner, but it could cause the Bluetooth device to flood the network. "We came up with that at a users' focus group," explains Nugent.
At the same time as these devices come into use, UPS is giving its drivers a new tool: the Diad 4, the latest generation of the mobile devices that UPS drivers have had since 1990, to collect signatures and track deliveries. The latest version is also by Symbol, while the first Diads were made to order by Motorola.
The company expects to have the whole system running in 118 countries by 2007, with something like 12,000 access points in 2000 offices. The project began with tests in Munich, and will be rolled out in earnest now, with 73 sites in operation by the end of 2005.
The installation is almost as interesting for the thigns it leaves out as for the things it puts in. RFID has had a lot of publicity, but UPs still feels the barcode has a few years' life in it, for assets as valuable as the packages it tracks.