Tuesday, June 23, 2009

4G Wireless Quietly Encroaching on 3G

To hear the cellular carriers describe it, the mobile world is going 3G wireless as the defined cutting edge technology available today. Meanwhile, a competing and faster technology is being slowly deployed, city by city, across the country. What's really going on?

It's actually little more than the usual pattern of technological improvement. It starts with an invention, in this case wireless data service, followed by steady improvements as time goes on. We saw this with the personal computer. Today's PC shares a lot of commonality with the one's of decades ago. You still have a CPU, disk drive, RAM, ROM, monitor, keyboard and mouse. But the speed and capacity of today's machines are orders of magnitude above the best you could buy years ago.

Mobile data is on a similar growth curve. WiFi hotspots are something of a unique product with a very limited coverage area, which is unlikely to change. Wide area mobile service is really the domain of the cellular carriers. By building an extensive network of towers and transmitting stations, they have wide footprint of wireless coverage for telephone calls. Piggybacking a data service on this same infrastructure is a logical and cost effective move.

What started as dial-up speed data service for mobile phones has been steadily improved down two paralleled paths, mirroring the two most popular types of cellular service. CDMA, used by Verizon Wireless, Sprint and Alltel, offers EV-DO and EV-DO Rev. A cellular broadband. GSM, used by AT&T and T-Mobile, offers EDGE and HSPA broadband. The latest incarnations are considered third generation or 3G. Access is now available through many if not most cell phones, wireless aircards used as adaptors for laptop computers, and built into the latest netbook computers.

The 3G services aren't done evolving, but they soon will be. AT&T wants to double it's current 3 Mbps peak speed over the next couple of years. Verizon and Sprint are on a similar upgrade path, perhaps a little faster at deployment.

But one carrier isn't waiting for the 3G marketplace to mature. They're already moving ahead to 4G. That carrier is Sprint, in combination with Clearwire. Since the company carries the Clearwire name, those not watching this closely might not realize that it's related to the competitive cellular business.

The 4G technology is WiMAX, which stands for Worldwide Interoperability for Microwave Access. It doesn't interfere with current cellular operations or use the same transmission frequencies. It's being launched in parallel with today's 3G networks. In a few cities you can have your choice of 3G or 4G. Download speeds for the 4G WiMAX service are typically 4 to 6 Mbps with bursts beyond 15 Mbps.

WiMAX also isn't being touted as a cellular technology. There's no cellphone service or handsets. Instead, WiMAX is being offered as a broadband Internet service for home or business, with a mobile service available through plug-in aircards like those used for 3G cellular. You can also get VoIP telephone service bundled, similar to what is offered by cable and telephone companies.

Where is WiMAX 4G service available? It's been deployed in Baltimore, Portland OR, and just recently Atlanta. The plan is also to launch service in Chicago, Charlotte, Dallas / Ft. Worth, Honolulu, Philadelphia and Seattle this year. By the end of 2010, Clearwire expects to be service 80 major cities in the U.S.

AT&T's 4G service will be based on LTE or Long Term Evolution technology. Verizon is planning a similar approach. LTE won't get started for a year or so, but it will follow a similar approach to WiMAX in that it will use different channels than those in use for 3G, so that both 3G and 4G services can exist simultaneously.

There is some thought that once 4G technologies mature, 3G will be phased out. Perhaps the current cell phone technologies will follow suit. The trend is toward converged IP networks for everything. That suggests that VoIP running on 4G networks along with data service on the same channels will be the new wireless communications technology.

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