HTC advances toward LTE-Advanced: The One M8 will support carrier aggregation

With the launch of its new flagship smartphone, HTC on Tuesday became the first device maker to trick out a U.S. phone with LTE-Advanced technologies. The new HTC One M8 supports an LTE-Advanced technique called carrier aggregation, which bonds together two downlink transmissions, amplifying both the speeds available to the device and the connection strength to the tower.

Samsung was actually first device maker to announce U.S. support for carrier aggregation in the Galaxy S5, but by virtue of the One M8 beating the GS5 to market (it went on sale today), HTC won the race. We’re likely going to see carrier aggregation offered in many smartphones going forward, especially as carriers increasingly deploy the technology in their networks.

HTC One M8 dot case

Both Qualcomm(s qcom) and HTC confirmed that carrier aggregation was available and enabled in M8’s baseband chip, but neither would comment on when individual operators would turn on the feature for their customers. A look at the specs on the Google Play edition of the One gives a good indication of where the feature will show up first though. The device will aggregate three bands all used specifically by AT&T(s t).

Right now AT&T is the only operator with aggregated networks (Ma Bell confirmed to Gigaom a few weeks ago that Chicago and several more markets were live) but Sprint is expected to begin combining its Spark network channels in the second half of the year, and both Verizon and T-Mobile have similar plans on their roadmaps.

So does this mean we’ve officially crossed the gap between plain-old LTE and LTE-Advanced? Not exactly.

LTE-Advanced is actually a grab bag of different technologies that will improve the speed, capacity, availability and resiliency of our 4G networks. Carrier aggregation is just the first step of many, but it’s also the one that gets the most attention because it produces something tangible to the end user: greater speed.

By bonding channels in different bands, AT&T is turning its patchwork of different 4G frequencies into a unified network. In the case of Chicago, AT&T is gluing together a 10 MHz downlink in the 700 MHz band and a 5 MHz downlink in the high-frequency Advanced Wireless Service (AWS) band, resulting in a 50 percent speed boost for customers capable of accessing it and theoretical capacity ceiling of about 112 Mbps.

Source: Flickr / FlySi

Source: Flickr / FlySi

Even with carrier aggregation, AT&T’s networks won’t be the fastest in the country. Both T-Mobile and Verizon are able to build faster systems because they have big hunks of contiguous spectrum — they can’t build anything bigger through channel bonding than they already have today. But as carrier aggregation techniques improve in the next generation of LTE chips, operators will be able to splice together some enormously fat pipes, capable of supporting theoretical speeds of 300 Mbps.

That kind of speed might seem ridiculous when talking about connecting a smartphone or when considering the high-cost of mobile data. But keep in mind that in the world of cellular networking, speed equals capacity. That 300 Mbps is divided among all of the users in a cell, so higher speeds make for a more efficient network and a better data experience for all involved.

The LTE baseband and Snapdragon 801 processor aren’t the only Qualcomm(s qcom) elements in the new One. HTC is also using Qualcomm’s envelope-tracking technology, which will cut down on power consumed by the LTE radio and is a likely contributor to the device’s 40 percent improvement in battery life over the previous HTC One.

Like most high-end smartphones, the new One M8 is actually has several variants to capture all of the various frequencies and radio technologies used by carriers in the U.S. The benefit to that approach is it will tap into the carriers’ newest networks. It will work on Sprint’s new Spark network, and Verizon’s new LTE monster. It will access not only the network T-Mobile has built in the AWS band but also the new network it’s building outside of metro markets at 700 MHz. And it will cover the gamut of AT&T’s four different 4G bands.

The Verizon and AT&T versions will be international 4G phones, tapping into global 1800 MHz and 2600 MHz LTE systems, but the T-Mobile and Sprint variants will be isolated to U.S. 4G networks.