From Bluetooth To 4G: What All Those Wireless Terms Really Mean

Wireless technology is evolving in ways we once only dreamed about, giving us fast connectivity from almost anywhere. But it is also devolving into a stew of acronyms and arcane trade names that sometimes confuse even those in the know.

"If this alphabet soup of names is confusing for industry people like me, I can't imagine what it's like for consumers," said Derek Kerton, principal of The Kerton Group, a wireless and mobile telecommunications consulting firm.

Kerton said it's helpful for users to understand the trade names and acronyms so they know what they're buying. But, he stressed, it's much more important -- and difficult -- to understand the risks, rewards and limitations of the various wireless technologies.

Since you won't always get straight answers to those questions from the vendors, here's a rundown of the most widely discussed wireless technologies and how they may -- or may not -- benefit you.

Short-Range Wireless

Short-range wireless simplifies the task of connecting one device to another, eliminating the tangle of cords and enabling you to roam away from those devices while you use them. While distances may vary based on different chipsets and impediments such as walls, these short-range wireless technologies typically have an optimal maximum range of 30 meters or less.

Bluetooth
Named after a 10th-century Danish king who united warring factions in Scandanavia, Bluetooth is a classic case of an overnight success that took years to occur. The first products with built-in Bluetooth came to market with great fanfare in 2000. From the start, lots of devices like cell phones were Bluetooth-equipped.Bluetooth devices multiplied rapidly, but most observers agree that Bluetooth has started being widely used only in the last year or so. Shipments of Bluetooth-enabled devices doubled in 2005, and an estimated half-billion such devices will be shipped this year. Among the more common applications for Bluetooth are wireless headsets for cell phones and portable music players.

The advantages of Bluetooth include low power consumption and the fact that, unlike the older IrDA technology used in PDAs and other devices before it, it uses omnidirectional radio waves. That means you don't have to point one Bluetooth device at another for a connection to occur, and it can be transmitted through non-metal barriers like walls. One big disadvantage is its speed -- the most recent version of the Bluetooth spec supports speeds of only about 2.1 Mbps. That compares poorly to old-fashioned Ethernet networks, which operate at about 100 Mbps.

Another problem can be that different Bluetooth applications require different so-called profiles, or set of behaviors that define how they communicate, and the devices at both ends of the connection must support the same profile. Usually this isn't a problem, but it can be if you're mixing and matching Bluetooth equipment. Practically speaking, if you are buying a Bluetooth-enabled phone, for example, make sure its profile matches the one used by your Bluetooth headset.

Ultra-Wideband (UWB)
The future of Bluetooth is tightly connected to that of ultra-wideband (UWB). Once thought to be competing technologies, the Bluetooth Special Interest Group (SIG), which represents Bluetooth vendors, says it will harmonize the technologies so that they work together.

UWB is a high-bandwidth technology with speeds well in excess of 100 Mbps, which is roughly 50 times faster than Bluetooth. That makes UWB a good choice for applications such as streaming multimedia from, say, a PC to a television. Some vendors are about to start shipping UWB gadgets -- the first should be those that distribute high-definition television (HDTV) signals.The problem that UWB has faced is that there are two competing UWB standards, which were developed by two separate organizations -- the WiMedia Alliance, which has the backing of such big-name vendors as Intel, and the UWB Forum, which is primarily backed by Motorola. The IEEE standard-setting body has given up trying to settle on a single standard. Instead, both are in the process of being released into the marketplace, although Motorola and Freescale have decided to focus on one permutation of their standard called Cable Free USB.

Also, the UWB standard developed by the WiMedia Alliance will be the basis of the Bluetooth SIG's efforts to harmonize the two technologies.

Kerton believes the Bluetooth SIG's decision settles the matter. "The UWB standards battle is over," he said. "The support from the Bluetooth Special Interest Group puts too much momentum behind the WiMedia Alliance, so that will be the standard that eventually succeeds."

Bluetooth and UWB won't be working together for at least a couple of years. In the meantime, UWB products from both camps will be available, which some fear will lead to a VHS/Betamax situation in which there is a risk of buying equipment that will soon be obsolete.

Other Short-Range Technologies

Two other short-range technologies you may hear about are near-field communications (NFC) and ZigBee. There's very little overlap between those technologies and Bluetooth and UWB.NFC has the shortest range of all -- it is designed to be embedded in mobile devices such as cell phones and even in credit cards. Using NFC, you can swipe your device within a few centimeters of point-of-sale terminals to pay for things. This technology is starting to spread in Korea and Japan and is being tested in the United States. Since it provides a fast, secure way of making payments, many industry analysts expect it to catch on quickly.

ZigBee is aimed at applications like wireless sensors that can be used for security and for in-building applications such as controlling heating and cooling systems. It, too, is widely expected to be a successful technology, although it will be a quiet success since it is built into machinery and other items that work in the background.

Medium-Range Wireless

While short-range wireless technologies connect one device to another, medium-range wireless technology is more commonly used to create local area networks of computers. This technology has been widely adopted both by enterprises and consumers, who continue to buy products at a rapid rate, according to most research studies.

Wi-Fi
If there's one wireless technology that most of us know about, it's Wi-Fi, which is a trade name for products that adhere to the IEEE 802.11 wireless networking standard.

Sales of Wi-Fi equipment for the home, small office, and large enterprise have been mushrooming for the last couple of years. In addition, the vast majority of laptops now come with built-in Wi-Fi, so road warriors have become accustomed to using wireless hotspots in coffee shops, bookstores, airports, hotels, and other common venues to connect to the Internet.

That's not to say that people understand Wi-Fi. Behind that trade name is a confusing plethora of standards and substandards. Networking Pipeline's "10-Minute Guide To Wi-Fi Standards" provides an in-depth look, but for now, here are the most important things to know about Wi-Fi.

As with all wireless technologies, Wi-Fi's range, or the distance signals can carry, varies widely depending on conditions such as how many walls are between the source of the signal and the device receiving the signal. With no impediments in the way, equipment based on the current 802.11g Wi-Fi standard has a theoretical range of about 100 meters. In practice, though, that range is typically less.

Similarly, the current 802.11g standard calls for speeds as high as 54 Mbps, but actual throughput typically is far less, usually about 20 Mbps. That's more than fast enough for most traditional networking applications, but it's arguably not fast enough for advanced applications like streaming multimedia. Various vendors have schemes, such as increasing the power used by the wireless transmitter and adding antennas, to add speed and range to 802.11g equipment.

The forthcoming 802.11n standard, which could receive final ratification late this year or early next, should boast real-world throughput of 100 Mbps or more. And because it will use multiple-input, multiple output (MIMO) smart antenna technology, its range should be much farther than 802.11g's, although it remains to be seen how far.

Most vendors of Wi-Fi equipment aimed at the home and small office are selling "pre-N" equipment that is based on the draft 802.11n specification. Based on reviews of this equipment, the jury is still out about whether it is as fast as advertised and whether it works with pre-standard equipment from other vendors. Nor is it guaranteed to be upgradeable when the official 802.11n standard is fully ratified. Even some Wi-Fi equipment vendors have doubts, delaying release of their products until these questions are resolved. In other words, when it comes to pre-standard equipment, buyer beware.

Wireless Mesh
Wireless mesh technology uses multiple Wi-Fi access points to create a wide-area network that can be as large, for instance, as the 135-square-mile network being developed in Philadelphia. Besides citywide networks, wireless mesh can also be used for campus-like situations. In either case, users only need devices that support Wi-Fi to be able to log on.

Because they cover a lot of territory, mesh networks could be considered wide-area networks (WANs), which are discussed in the next section. They're also sometimes referred to as metropolitan-area networks (MANs). However, we put mesh networks in this section because they really are a series of interconnected local area networks.

Some believe large mesh networks won't work well because the portion of the wireless spectrum those networks typically use -- the 2.4 Ghz portion -- is unlicensed and unregulated by the government. That means there are many potential sources of interference, such as personal Wi-Fi networks, that operate in the same 2.4 Ghz band of the wireless spectrum. By contrast, use of the licensed spectrum, such as that used by cellular operators, is tightly controlled and is far less susceptible to interference.

"Say I have my own wireless network and I live in Philadelphia," Kerton explained. "If I use a [wireless] channel and the city's network uses the same channel, what will happen to the network inside my house? Or, for that matter, people who deploy Wi-Fi in their home or business could interfere with the city's mesh network."

Proponents of mesh networks say their technology can deal with such interference. That may be true, Kerton said, but he stressed there just isn't enough experience with large mesh networks to know the answer -- yet. While a few small networks already are in place and the results have for the most part been favorable, large networks such as Philadelphia's won't be fully deployed for about a year.

Wide-Area Wireless Networks

Nowhere is the acronym stew more confusing than it is with wireless networks that cover wide areas. There are several basic types of technologies used for this sort of connectivity, each of which has its own series of acronyms. Worse, each of those technologies is evolving, with future generations having different names (and acronyms) than the current generation.

The similarity among all these different types of networks is that they connect you to the Internet without wires over wide swatches of territory. One more thing to understand is that these networks typically operate over licensed spectrum. That is, they use portions of the wireless spectrum that are regulated by the government. By contrast, technologies like Wi-Fi and Bluetooth operate over the unlicensed spectrum and are more prone to interference and security problems.3G Service
Cellular operators have been touting third-generation, or 3G, cellular data service since well before the turn of the century, and in the last year, it has finally arrived. This service provides decent data throughput speeds -- currently about 500 Kbps, give or take -- over the networks run by cellular operators.

While not as fast as most wired broadband connections, 3G offers one tremendous benefit: Like cellular voice service, it is readily available throughout a cellular operator's service area. All you need is a card for your laptop or a mobile device that supports the service.

But here the acronym soup starts to boil furiously. Some of the confusion is created by the fact that, in North America, there are two separate core technologies used by cellular operators. Some operators, such as Verizon Wireless and Sprint, use CDMA (Code Division Multiple Access) technology. Others, such as Cingular, use GSM (Global System for Mobile Communications) technology.

Cellular operators that employ CDMA technology currently are using 1xEV-DO (Evolution-Data Only) 3G service, which is sometimes called CDMA2000. That will migrate to EV-DO Revision A starting in a year or two, which will provide speeds of roughly 1 Mbps. GSM operators use UMTS (Universal Mobile Telecommunications System), which is sometimes confusingly called WCDMA (Wideband CDMA). That technology already is evolving into HSDPA (High-Speed Downlink Packet Access), which eventually will evolve into HSUPA (High-Speed Uplink Packet Access).

Adding even more confusion is the fact that these technologies have both theoretical speeds and real-world speeds. For instance, HSDPA has a theoretical maximum throughput speed of more than 3 Mbps. Current real-world speeds, however, are in the 500 Kbps to 700 Kbps range. When considering 3G, make sure you are clear whether the speeds the vendors are promising are theoretical or actual speeds you can expect.

Another caveat is price -- this stuff is expensive. The going rate for 3G service in the U.S. is $60 a month on top of a voice plan and a two-year contract, more if you don't have a voice plan with a specific carrier. You'll also need a 3G card for your computer or a mobile device, such as a smartphone, that supports your cellular operator's flavor of 3G. You get those from the cellular operator, and prices vary widely depending on your service plan and contract length.

Yet another gotcha relates to the fact that some carriers call their 3G service "unlimited." However, if you read the fine print, you'll find that it's anything but unlimited. Most carriers limit how much you can download and what the service can be used for. For instance, some carriers prohibit use of this service for downloading or streaming audio or video. If you go beyond the limits, the carriers reserve the right to cut your service.

4G And Wireless Broadband
These wireless wide-area technologies promise soul-stirring connection speeds no matter where you are -- some day. That, in turn, according to the promises of equipment vendors, will open the way to all manner of new mobile technologies such as television and movies on the go.

While nobody doubts these technologies are coming -- and some already are starting to be available -- the Acronym-Annoyance Meter starts going off the charts when talking about 4G and wireless broadband.

In general, these future technologies fall into two categories. Fourth-generation, or 4G, refers to fast wireless data access that will eventually be provided by cellular operators to replace 3G technologies. "Wireless broadband" is fast wireless technology that is starting to be offered by so-called wireless ISPs but that also could be offered by cellular and traditional telecom operators.

The best-known brand of wireless broadband is WiMAX, which is based on the IEEE 802.16 standard and has been championed by Intel, among other industry heavyweights. However, other brands of wireless broadband are also currently available, most notably FLASH-OFDM, which is being championed by Qualcomm, and UMTS TDD, which is from a smaller company called IPWireless.

Unlike its wireless broadband competitors, WiMAX is not yet mobile. Rather, it currently is only a point-to-point technology, like a wireless version of your existing DSL or cable connection. The mobile version of WiMAX could start becoming available in pre-standard form later this year or early next year. Official approval of the mobile WiMAX standard isn't expected, however, until at least the end of this year or early next year. By contrast, FLASH-OFDM and UMTS TDD are mobile technologies; they are also available now but have not been as widely deployed as WiMAX.

Here's the tricky part: 4G and wireless broadband networks may turn out to be the same thing in the end.

Wireless broadband networks currently are based on a technology called Orthogonal Frequency Division Multiplexing (OFDM). While OFDM technology such as WiMAX is starting to be available from wireless ISPs, many believe that some future form of OFDM will be used by the cellular operators for 4G access. In particular, Qualcomm is laying its bets that Orthogonal Frequency Division Multiple Access (OFDMA) will be adopted by cellular operators in the future.

Currently, Sprint in the U.S. is furthest down the wireless broadband/4G path. It is evaluating WiMAX, FLASH-OFDM and UMTS TDD and says it will pick one of those technologies this year and start deploying it next year. In its literature, Sprint sometimes refers to this technology as 4G technology, even though wireless ISPs will be offering the same technology. It isn't saying, however, what it will do with this technology once it is deployed.

In other words, the crystal ball is hazy, to say the least, about the future of wireless and mobile access. The good news, according to Kerton, is that we don't have to worry about what's in the future. Nor do we have to worry about all the acronyms and funny names."The most important thing about wireless technology isn't the alphabet soup [of acronyms], but how fast it is, how much can I use, what does it cost, and where does it work," Kerton said. "If you ask those questions, it doesn't matter what the acronym is."