Electronic Design

Short-Range Wireless Needs Long-Range Plans

Try to remember what the booming short-range wireless technologies were 10 years ago. Nothing comes to mind except for garage-door openers, CB, and a few ISM (industrial-scientific-medical) radios. Since then, a deluge of short-range wireless technologies has descended on the masses.

Developments went from a yawn to hyperfrantic information overload. And there’s no stopping them, with short-range wireless devices now embedded in almost every electronic product. Bluetooth and Wi-Fi dominate such connectivity, but standards like Ultra-Wideband (UWB) and WiMAX are making progress.

Bluetooth
Bluetooth stands tall among the wireless standards simply because it leads the pack in worldwide device deployment. With chip shipments exceeding 1 billion, no other wireless technology comes close.

Half of today’s cell phones—which have the highest volume sales of any consumer product on the planet—contain Bluetooth for hands-free cordless connectivity to handsets. Bluetooth also is popular for other wireless connections in the automotive, consumer, PC, and PDA markets.

CSR is the leading Bluetooth chip provider, taking 60% market share. Its fifth-generation technology packs Bluetooth connectivity into a single chip. CSR offers versions with a multimedia processor for noise-cancellation software and various voice-processing applications. Other versions include a built-in FM radio.

The forthcoming 3.0 version of the standard will feature a UWB physical layer (PHY). These Bluetooth radios, which use the WiMedia orthogonal frequency-division multiplexing (OFDM) standard, should work in the 5-GHz range rather than the 3.1- to 4.9-GHz range of wireless USB UWB radios. The complete standard won’t be ratified until December, but expect some new Bluetooth applications that require data rates in excess of 100 Mbits/s, like video.

Ultra-Wideband
The first UWB products are a far cry from what was originally imagined. But the result is a new wireless technology with a solid niche, in this case wireless USB. Most companies that make UWB chips follow the WiMedia Alliance standard based on OFDM. Their products address the wireless USB applications of PC and laptop connectivity to peripherals, digital cameras, and other high-data-rate extensions (Fig. 1 and 2).

Since UWB has the potential to achieve 480 Mbits/s, it’s seriously being considered by companies seeking to integrate wireless video connectivity in consumer electronics. Despite its limited range, UWB certainly can support video. But can it deliver the required performance?

Nonetheless, UWB is a winner, and future developments will further broaden its usage. In fact, the Bluetooth Special Interest Group has made UWB its next PHY of choice. Future versions of UWB will exploit bands beyond 4.9 GHz, opening new possibilities and providing versions that are more compatible with the spectrum and regulatory limitations of other countries. What once was considered an exotic wireless technology is turning into one of the most flexible.

Wi-Fi
Next to Bluetooth, Wi-Fi is by far the most successful and widely deployed short-range wireless technology. What laptop doesn’t contain an 802.11b/g transceiver that lets you get online via the hundreds of thousands of hot spots worldwide or through your own wireless home network?

Research firm ABI indicates that at the end of 2006, there were 147,300 Wi-Fi hot spots worldwide. Europe leads the way—and that doesn’t include the hundreds of thousands of regular local-area-network (LAN) access points.

Work continues on the next version of Wi-Fi, designated by the IEEE as 802.11n. It promises better than 100-Mbit/s service with greater reliability thanks to its multiple-input multiple-output (MIMO) antenna technology. A first draft of the standard is complete, but final details are being ironed out by the IEEE Task Group.

In the meantime, chip and wireless LAN equipment companies are going ahead with pre-n or draft-n versions of their products. The Wi-Fi Alliance also initiated a testing and certification procedure of the draft-n products that will begin in July this year. Final ratification isn’t expected until early 2008.

The big news surrounding Wi-Fi is the rapid build-out of municipal mesh networks. Cities across the U.S. have installed mesh Wi-Fi networks open to citizens, travelers, and city employees. Mesh topology lets individual nodes, with their usual restricted range of about 300 feet, talk to one another and relay data from one to another.

As a result, super-low-cost nodes can cover many square miles. Over 350 new mesh Wi-Fi networks were installed in the past 30 months, according to Karen Hanley of the Wi-Fi Alliance. Expect that number to grow.

Dual-mode cell phones have taken to Wi-Fi too, providing Voice over Internet Protocol (VoIP) calling using the Session Initiation Protocol. They’re available now, and cell-phone network providers are testing out the service. Problems such as handoffs between cell and Wi-Fi, high handset power consumption, and using one rather than two phone numbers still must be resolved. Still, it could be another profitable niche for Wi-Fi.

WiMAX
WiMAX, a broadband wireless technology, is based on the IEEE 802.16 standard. The 802.16-2004 standard is for fixed and nomadic operation, while the 802.16e-2005 version targets mobile use. There’s still considerable interest in the fixed version for broadband wireless services as a competitor to cable TV and DSL.

But now with the mobile version approved, the application possibilities expand dramatically. Some experts even say WiMAX using VoIP will be the basis of fourth-generation (4G) cell-phone systems. That remains to be seen, but WiMAX probably will get a piece of the VoIP business. It will become part of the bundled services offered by major WiMAX adopters such as Clearwire and Sprint Nextel.

One likely application will be Internet access via mobile laptops using embedded WiMAX chip sets. WiMAX will deliver higher speeds over longer distances than Wi-Fi, which is currently built into every laptop. Also, WiMAX will do so in a mobile environment, which isn’t possible with Wi-Fi. Look for WiMAX in laptops as carrier services build out in the future. You’ll see some dual-mode WiMAX/Wi-Fi capability as well. Expect WiMAX rollouts late this year and throughout 2008.

The New Kids On The Block
With all of the available standards, there’s significant overlap in coverage. Thus, almost any new application becomes a target for any given standard. But each technology has been more or less finely tuned to specific needs, so we continue to see new technologies emerge, like Wibree and Wireless HD.

Wibree is a radio technology with super-ultra-low power consumption. It’s designed for connectivity between PCs, cell phones, and other mobile devices, as well as button-battery-powered devices like watches, wireless keyboards, toys, sports sensors, and some medical devices. Developed by Nokia, Wibree operates in the 2.4-GHz ISM band with a 1-Mbit/s data rate and a range from 5 to 10 m.

Final details of the specifications have yet to be decided. Low power and automatic linkup hold the keys to it all. Wibree devices are expected to operate either in standalone or dual mode along with Bluetooth. Since the standard is still being developed, it’s unclear when the first silicon will be available or when the first products might emerge.

Wireless HD (WiHD) targets consumer electronics, and the HD probably means high-definition TV. Despite the potential of 802.11n Wi-Fi and UWB for video transfer, some experts say neither can deliver the kind of performance required by a home network that includes TV sets, DVD players, DVRs, games, cameras, and the computers that work with these products.

The goal is to stream uncompressed HD video as well as audio over short distances. The WiHD standard is expected to use the unlicensed millimeter wave band at 60 GHz. At this frequency, data rates of 2 to 5 Gbits/s are realistic, with a potential of up to 20 Gbits/s.

At 60 GHz, the range will be pretty short. But smart antenna technology can be brought to bear to make solid point-to-point links over a line-of-sight (LOS) path. Non-LOS also should be possible. WiHD is still in definition, so look for more information later in the year.

For more, see “What’s Happening With ZigBee.”

TAGS: Automotive
Hide comments

Comments

  • Allowed HTML tags: <em> <strong> <blockquote> <br> <p>

Plain text

  • No HTML tags allowed.
  • Web page addresses and e-mail addresses turn into links automatically.
  • Lines and paragraphs break automatically.
Publish