A status report on wireless standards: Wi-Fi, Bluetooth and ZigBeedifferent standards set to meet different application needs – Mobile/Wireless
The primary difference among the major open wireless standards is definition–definition of the technical specification, definition of actual products and definition of applications. For many, Wi-Fi, Bluetooth and ZigBee are all lumped into the same category, when in fact they represent very different stages of development and offer varying degrees of potential. The trick is to adjust your expectations according to the level of definition and then determine how each fits into the polyglot of the wireless infrastructure.
Wi-Fi, or 802.11b, is a mature, well-established standard that continues to grow and evolve. This year the Wi-Fi Alliance began certifying the two newest versions of the specification–802.11a and 802.11g–and saw a dramatic increase in shipments of 802.11g products.
“One of the advantages of 802.11g technology is that it is backward compatible with products based on the earlier version, 802.11b, which are already on the market,” says Brian Grimm, communications director of the Wi-Fi Alliance. “And soon that backward compatibility will include 802.11a systems. So if you have an 802.11g infrastructure, it will support all of your old and newer equipment.”
In this case, backward compatibility is important because so many older wireless systems are still in use on factory floors and in warehouses.
“Those are the companies that purchased the systems years before 802.11b ever came into existence, before that standard was effectively completed, which means that those legacy systems have now reached the end of their operational life and need to be updated to 802.11b or g or a,” says Sarah Kim, a wireless and mobile technologies analyst with the Yankee Group.
With the newest iterations of the specification come enhancements in performance. “We are seeing both faster and more secure technology that will enable people to share various types of information and help them serve their customers better,” says Grimm. “What we have now is an infrastructure technology that will allow us not only to show a signature or a data stream of text, but now because of higher data rates, we can actually have pictures or a video of the production stream running over the same Wi-Fi bandwidth to monitor various points in the distribution assembly and at the dock for security and other applications.”
And because most of these applications will require protection, there is a new open enterprise-class security solution called Wi-Fi Protected Access (WPA). Products with this feature began shipping in April, and there are now over 70 WPAenabled-products on the market.
Quality of service (higher data rates) to enhance voice/video transmissions and improved security look good on paper, but what value will companies place on these new features?
“I think next year’s technology is going to change in one area: quality of service–better support for voice and video streams. To the extent that is applicable in supply chain management, that would be good,” says Grimm. “But my perception is that it will be less important than the availability of applications that use wireless to improve efficiency. I think we’re going to begin seeing applications emerge that are less dependent on wired networks and more dependent on wireless networks to gain those efficiencies. And I don’t think that is necessarily going to depend on the evolution of the technology.”
Whatever the added features, whether video or new applications, vendors must remember the legacy systems that are already in place and from which companies must migrate.
“You can get into the alphabet soup of everything–you know factor speed, quality of service and everything else that we are so mired in,” says Kim. “But the people that are using this for real applications, who have hundreds or thousands of access points, don’t really care about quality of service and all of this other stuff. It’s the basics. They have a whole bunch of readers, scanners, printers and devices of all sorts that they’ve put significant investment into, and they can’t afford to change their entire infrastructure overnight.
“Until now, though, most of those organizations really didn’t want to change because they had put so much money into it and it was working fine,” Kim continues. “It’s only now that they’re beginning to see that these products are inexpensive, their suppliers are no longer going to support what they have, and there is an opportunity to shift into something that’s better and easier to manage and can offer them future functionality as they need it. I don’t think they’ve necessarily thought of the applications that will take advantage of these new features, but they know they have to move.”
Bluetooth is behind Wi-Fi in the evolutionary process, but it’s just now breaking stride. The specification is complete, enhancements have been made and products are available on the market.
While devices based on the original specification experienced problems involving interference, poor voice transmissions and slow connection times, the newest version of Bluetooth aims to correct these shortcomings. “The idea behind Bluetooth 1.2 is to clean up version 1.1–to improve features and solve problems identified during the deployment of 1.1 devices,” says Stephen Shellhammer, senior director of technology development for Symbol Technologies Inc.
First on the list of improvements is adaptive frequency hopping. This feature minimizes mutual interference between Bluetooth and frequency-static systems (802.11 networks) and makes it possible for different wireless implementations to coexist in the same environment. This ensures that a company can integrate its wireless networks into a reliable supply chain management infrastructure.
Adaptive frequency hopping will “allow Bluetooth devices to operate more effectively in settings where wireless LANs are also installed, such as most large retail stores and many warehouses,” says Barry Issberner, vice president of vertical marketing at Symbol.
Version 1.2 has also corrected the problems associated with voice transmissions, and it now better supports cordless voice headsets for applications such as voice-directed picking systems in a warehouse.
And with the new version, connecting multiple Bluetooth devices can be accomplished much faster. These improvements have made Bluetooth-enabled devices more appealing to companies and reduced their reluctance to adopt the technology.
“This is the first year that Bluetooth has shipped in big numbers,” says Kim. “If you go to their Web site, there are several hundred devices or actual products that have made it to the market–as products rather than chip sets and components, as it was in years past.”
These products are being used more for things like scanners and near-field communications, and they are achieving more traction in specific verticals (e.g., health care).
“On the enterprise side, it’s a lot more hopeful [than the consumer market] in that you have companies that have specific needs, who have big budgets–like UPS–and are taking the lead in testing the technology for very specific applications,” says Kim. “But really, it’s a very niche technology at this point.”
ZigBee is not a standard yet, but the alliance was scheduled to release version 0.75 to its members last December. “That’s the first time we’ve had a complete framework,” says Barry Rudolph, a prominent participant in the ZigBee Alliance. “Over the next nine months, we will be making comments and minor revisions to the specification. But we won’t be seeing real product implementations of ZigBee until the second half of the year.”
“ZigBee is the least mature of the three standards,” says Yankee’s Kim. “Most people haven’t distinguished the difference between 802.15.4 and ZigBee. The first is actually a radio standard under the wireless personal area network (WPAN) family, and ZigBee is the specification defining the networking applications layer needed to support that caliber of ability in those kinds of devices.”
While this specification may not be ready for prime time, it does hold out the promise of some interesting features. ZigBee is designed for low-power operation. “You could leave a ZigBee device out in the field for an extended time and not have to worry about it. This eliminates the necessity for operators to go out and recharge or change the battery often. That would let companies reduce their labor costs,” says Rudolph.
ZigBee also offers greater range than Bluetooth. “You can pass data via mesh. ZigBee is the first time the mesh network is standardized within a specification. So the ability to create a network without hooking up lots of infrastructure in between is unique,” says Rudolf.
ZigBee is also designed to service simple devices with low data transmissions. According to Rudolph, “ZigBee is not going after segments that require the exchange of high-bandwidth data, such as graphics and video. It’s really going after the industrial supply chain market, where you don’t need a lot of bandwidth.” In addition to still being in the process of defining its specification, products and applications, the ZigBee Alliance is also working to acquire credibility.
“There are members of that organization who are not necessarily using ZigBee, but who are using the ZigBee organization as a way to gain traction for their own technology (i.e., proprietary systems),” says Kim. “There are members of that organization who have products, who are using proprietary systems and who have other members with that organization that are purchasing and using these proprietary technologies. What is the commitment of these big players to ZigBee as a technology?”
A Mixed Bag
All of the standards are developing simultaneously and will be vying for the same IT budgets. But most companies don’t think that one technology can meet all their needs.
“Vendors will have to be smarter,” says Yankee’s Kim. “They can’t just walk in and expect to sell the technology. They have to be able to solve the problem using a multitude of technologies, and they all have to work together.”
Mountain View, Calif.
The Yankee Group
San Ramon, Calif.
For further reading on this and related topics, see these articles, available at www.frontlinetoday.com/102003links:
“Achieving Interoperability in WLANs” December 2003
“Wireless LAN Security” October 2003
“New WLAN Standard Nears Completion” April 2003
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