When smartphones came into wide use for Internet access and data transmission, consumers and carriers quickly recognized the need for faster, more reliable wireless data networks with broader geographical coverage. The current mobile telecommunications technologies, collectively known as 3G, for third generation, emerged about 10 years ago. At long last, successor technologies are now entering commercial service. The whole idea behind 4G is that it will offer very fast, widely available broadband.
4G, the fourth generation of cellular wireless standards, will provide high-speed transmission that supports high-quality streaming video. 4G technologies include mobile WiMax and Long Term Evolution (LTE). 4G isn't backward-compatible with 3G, but it uses spectrum more efficiently.
The two main 4G technologies are WiMax and Long Term Evolution. WiMax is a wide-area standard from the IEEE. LTE is the latest standard from 3GPP, an industry group that brought out the earlier 3G networking technologies.
Both WiMax and LTE use advanced antenna technology to improve reception and performance, but each uses different parts of the wireless spectrum. Neither will operate at current cell phone frequencies, and neither natively supports voice transmission. Therefore, today's 4G phones must include a 3G chip to handle voice calls and enable roaming between carriers and geographic areas.
As of last month, Sprint Nextel Corp. was the only carrier offering 4G service in the U.S. To deliver that service, Sprint uses WiMax technology on the Android-based HTC EVO 4G and Samsung Epic 4G phones. Verizon Wireless has said that it expects to ship LTE phones by mid-2011.
Different providers can choose different 4G technologies, but their offerings typically provide four to 10 times the throughput of 3G networks. The faster downloads and better streaming of 4G accommodate the quality-of-service and rate requirements for existing 3G applications and will significantly improve the performance of demanding applications such as video, chat, videoconferencing, multimedia messaging, networked gaming and HDTV.
In the future, users may be able to replace their home broadband service with a 4G service that could also be used on the road. It might be cheaper to have WiMax 4G service rather than home service plus a 3G wireless plan. Developers are aiming for download speeds of 100Mbit/sec. with 4G, but products capable of that level of performance probably won't appear for a few years.
One eventual goal is for 4G to enable pervasive computing -- currently a hypothetical concept -- where multiple simultaneous high-speed network connections will provide users with seamless handoffs throughout a geographic area.
Kay is a Computerworld contributing writer in Worcester, Mass. Contact him at firstname.lastname@example.org.
4G: Who's Got What?
4G service is currently available in several countries. Japan, Korea and Russia have WiMax networks, and a commercial LTE network is running in Sweden. Here's a rundown of 4G plans in the U.S.
* AT&T Inc. plans to use LTE when it eventually upgrades to 4G in 2011, but for now it's sticking with its current 3G network.
* Verizon Wireless is testing LTE equipment from several vendors, and it plans to begin rolling out 4G this year and to cover most of the country by 2012. The company hasn't announced LTE pricing.
* Sprint is partnering with Clearwire Corp. to offer WiMax-based 4G service in nearly 50 major U.S. markets. Clearwire/Sprint's 4G plans typically include unlimited data access, whereas most 3G plans charge extra for downloading more than 5GB per month. Clearwire-based plans are commonly $10 to $20 per month cheaper than 3G data plans. Clearwire recently announced an effort to roll out and test systems that incorporate both LTE and WiMax technologies.
* T-Mobile USA is launching a 3G variant (sometimes called 3.5G) in 100 U.S. cities. The carrier is expected to offer LTE services sometime in the future, but it has not set a specific date for doing so.
* MetroPCS Communications Inc. plans to introduce LTE in Las Vegas before 2011 using a dual-mode 3G/LTE phone by Samsung.
* U.S. Cellular will probably use LTE when it offers 4G service, but it hasn't announced a schedule for doing so.
Sources: News reports, GigaOm.com and PC World
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This story, "QuickStudy: 4G Wireless" was originally published by Computerworld.