Starting today, there’s a new, faster breed of cell phone Web access out there. HTC’s EVO 4G, available on Sprint, is the first phone that uses WiMAX, a technology that allows fast wireless Internet over long distances. This week, Technology Review previewed this new era of mobile connectivity.

The EVO is the most powerful phone running the Android operating system on the U.S. market. With the Qualcomm 1GHz Snapdragon processor (also found in Google’s Nexus One) and 512 megabytes of random-access memory, it packs more punch than both the Nexus and the latest iPhone. The EVO is also a physically bigger beast, with a chunky, cuboid shape and 4.3-inch LCD touch screen, compared to the Nexus One’s 3.7-inch window and the 3.5 inches of the iPhone 3GS.

But the real news here is the EVO’s WiMAX chops, which have never been seen before in the cell-phone market. Sprint says its “4G” service–as it brands its WiMAX network–makes the EVO capable of downloading up to 10 times faster than today’s 3G network.

Until today, only modems for full-size computers could use the newer network which has so far only rolled out in 33 cities, covering an estimated 41 million people. The nearest coverage to this San Francisco-based reporter is 500 miles away, in Las Vegas, but I took the EVO south to Palo Alto, where wireless Internet service provider Clearwire runs a 20-square-mile WiMAX network to encourage Silicon Valley developers to build apps for the new technology.

Although this Clearwire “sandbox” network doesn’t offer as polished a service as a full consumer WiMAX installation would, when the EVO locked on to a WiMAX signal, the difference was obvious. Web browsing became smoother, videos loaded more quickly and skipped less often, and streaming video live to the Web via Qik was much improved. The Android app provided by Speedtest.net reported download rates consistently over four megabits per second, compared to the consistent one megabit per second I saw using 3G on the same device in the same spot. (WiMAX seems to consume the phone battery faster, too, alas.) With the EVO’s hot spot feature, I got it to function like a pocket-size wireless router so that my laptop could share the connection.

WiMAX isn’t really 4G in the eyes of the International Telecommunication Union (ITU), a U.N. body that defines wireless “generations” and formalizes their technical specifications. To be 4G, a mobile device like a cell phone must offer a connection of at least 100 megabits per second. WiMAX’s speeds can peak over 100 megabits per second, but it can’t reliably reach 4G-grade delivery, and Sprint’s network currently offers six megabits per second at most. For now, though, “WiMAX provides data service at the highest available rate,” says Zhi Ding, an electrical engineering professor at University of California, Davis, who leads a research group working on improving wireless communications.

The feature of WiMAX most responsible for its speed, says Ding, is something called OFDMA, or orthogonal frequency-division multiple access. It’s a way of transmitting digital wireless signals that allows a base station to split a chunk of radio spectrum into multiple subchannels. By varying the number of channels assigned to each user and the power of those channels, OFDMA ensures a good connection everywhere, regardless of where the nearest base station is or how many buildings are nearby reflecting signals. “This dynamic quality of service is much less sensitive to overload and cell size,” says Ding.

Sprint’s competition, however, will catch up soon enough. Last year, Verizon and AT&T announced plans to upgrade existing 3G networks to an enhanced version of today’s 3G technology called LTE, or long-term evolution, and this technology is already being tested in selected cities. Ding says that Verizon estimates that LTE will be in service by the first half of 2011.

Operators face some tough decisions about how much to invest in building up new networks, since it’s hard to know how many new subscribers will be drawn in by the new technology to pay for the capital costs of infrastructure. “The iPhone phenomenon may be a good hint,” Ding says. Giving access to highly desirable mobile services can motivate people to switch carriers in large numbers, a phenomenon that the EVO’s backers hope to emulate.

True 4G phones by ITU standards will be a little longer in coming. The ITU is currently considering improved versions of both LTE and WiMAX as candidates for its specification for the next generation of wireless links, but that process isn’t expected to be complete until the end of this year at least, making the true heirs to today’s wireless a few years off.