Clearwire LTE wireless passes 90 Mbit/sec in Phoenix test

Says that the LTE speeds were 10 times faster than Clearwire's Wimax network

CHICAGO -- Clearwire's trial LTE network exceeded 90 MBit/sec in specialized tests in Phoenix, running more than 10 times faster than what the company says is the average speed of the WiMax downlink it operates in 55 U.S. markets.

The vastly higher speeds could prove a boon for future applications such as high quality wireless videoconferencing, augmented reality and others not yet envisioned, Clearwire officials said at the 4G World conference here.

Clearwire officials said the test, which was described in a video presentation, showed that the LTE technology could produce average speeds of 20 to 70 Mbit/sec for real world applications, depending on the number of users connected wireless to a single base station or cell tower and how far away they are. The technology should allow for average speeds of 50 Mbit/sec, the company added.

By comparison, a 3G smartphone on the market today generally downloads files at 300 Kbit/sec.

The trial speed of 91.3 Mbit/sec in the Phoenix trial was conducted in what Clearwire called a special way of using LTE, or 2xLTE, running in two parallel channels of 20 MHz each over the 2.5 GHz band. It has also conducted tests with what it calls 1xLTE, using two 10 MHz channels running in parallel.

While the downlink over 2xLTE exceeded 90 Mbit/sec, the uplink in the tests exceeded 30 Mbit/sec, Clearwire said.

The trial used client radio cards sold commercially by Samsung and used in Norway today for speeds of 50 to 70 Mbit/sec., said Mike Sievert, Clearwire's chief commercial officer. Devices that can handle such speeds are rare in the U.S. today.

Still, the trial speeds are "exciting news," Sievert said. "What you have here is something massively different than anything that's come before."

Clearwire announced plans for the LTE trials in August, saying then that the company is technology agnostic and is still committed to WiMax technology.

The company noted that other carriers such as Verizon Wireless were advertising that average speeds of their LTE technologies would be in the 5 to 12 MBit/sec range. Verizon has recently said it will have 38 U.S. markets on LTE by the end of 2010.

WiMax and LTE have been seen in the U.S. as competing technologies. Clearwire and its majority owner, Sprint Nextel, have committed to rolling out WiMax networks nationwide to 55 markets serving 63 million people. Clearwire announced this week that New York City's WiMax network will come online on Nov. 1, while Los Angeles will get Wimax on Dec. 1 and San Francisco in late December.

The trial speed of 91.3 Mbit/sec in the Phoenix tests was conducted by Clearwire engineers, who used some Wimax gear, including the cabinets holding modular Wimax gear that are already atop some buildings in Phoenix.

"Our goal is to see WiMax continue to grow, so it's not a question of whether will it stay," Sievert said in an interview. "We are a company actively investing in [WiMax] technology and rolling it out in one of the biggest network buildouts in wireless history, so obviously we're believers."

But Sievert added that he could not predict when or how Clearwire's support for LTE will evolve, though in August the company made it clear that it recgnized there will be many smartphones, tablets and other devices running on LTE, devices that Clearwire wants to be able to connect to its network.

Sievert noted that Clearwire already sells mobile hotspots that connect to Wi-Fi and WiMax as well as Wimax USB dongles. Sprint sells two 4G smartphones that run over WiMax, including the HTC Evo 4G and the Samsung Epic 4G, and Best Buy has committed to sell more than 20 laptops with WiMax access embedded.

AT&T, which will offer LTE in 2011, reacted to the Clearwire Phoenix test, with AT&T spokesman Mark Siegel saying, "This is an example of the over-hyping of 4G. If you're the only car on the road, it's not hard to go fast."

Matt Hamblen covers mobile and wireless, smartphones and other handhelds, and wireless networking for Computerworld. Follow Matt on Twitter at @matthamblen, or subscribe to Matt's RSS feed . His e-mail address is

Copyright © 2010 IDG Communications, Inc.

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