Sprint’s 8-antenna LTE tech moves out of the labs and into Chicago

Sprint’s(s s) big Chicago event on Monday may have all about smartphone exclusives, HD voice and fitness and family apps, but CEO Dan Hesse also provided an update on a new technology making its way into Sprint’s LTE network. For the last year, Sprint has been testing a new antenna technology called 8T8R, which would boost capacity and coverage in its LTE network, and that technology is now deployed on a trial basis in Chicago.

8T8R stands for “eight transmitters/eight receivers”, and it’s basically the smart antenna technology we now know as multiple input-multiple output (MIMO) on steroids. Today’s LTE systems mostly have two transmitting antennas and two receive antennas at the cell site. As its name implies, 8T8R quadruples those numbers.

Dan Hesse speaking at Sprint's Chicago event (Photo: Kevin Fitchard)

Dan Hesse speaking at Sprint’s Chicago event (Photo: Kevin Fitchard)

If there are more antennas at the tower, that means more signals are flying at your phone or tablet, creating much stronger signals and more resilient wireless links even at the fringes of a mobile cell where reception is always spotty. On the return path to the tower, more antennas can help pick your phone’s generally weaker signals out of the airwaves.

So 8T8R isn’t going to boost the overall speed of the network, but it will help even out the wild peaks and dips in performance you usually experience when moving through the network. Basically it means you’ll experience faster speeds in more places, instead of only when you’re near a tower. Hesse said Sprint has seen huge improvements in mobile broadband coverage in its tests: between 20 percent and 25 percent in urban and suburban areas and up to 70 percent in flat areas like highways.

T-Mobile(s tmus) has done similar upgrades to its own networks, but instead of using eight antennas it’s only using four (think 4T4R rather than 8T8R). It’s managed to commercially launch its 4×2 MIMO technology in its LTE systems in several cities and plans to make it a key component of its new wideband LTE rollout, which will double the speeds and capacity of its network.

A rooftop loaded up with multiple wireless antennas (Source: Flickr / FlySi)

A rooftop loaded up with multiple wireless antennas (Source: Flickr / FlySi)

Sprint considered rolling out four antenna rigs when it launched its Spark network last year, Hesse told me, but Sprint decided to hold out for 8T8R’s additional multiple of antennas in order make Spark the most sophisticated 4G network of its kind when fully deployed. Hesse said all three of its network equipment suppliers — Nokia(s nok), Alactel-Lucent(s alu) and Samsung — have worked the kinks out of the technology and it should be ready for commercial rollout later this year.

What Sprint is calling Spark is actually a combination of multiple technologies and three LTE networks on three different frequency bands, but not all of those components are yet in place. As it stands now, Spark is really only an average LTE network compared to the competition and it’s only available in 27 markets.

But by the end of the year, Sprint plans to pile a lot more spectrum onto the network using an LTE-Advanced technique called carrier aggregation. Combine that with Sprint’s planned antenna frenzy, and Spark will become a lot more impressive.

This post was updated at 6:45 PM PT to correct Sprint’s list of TD-LTE vendors.