SK Telecom uses fancy antennas to hit LTE speeds of 600 Mbps

SK Telecom just last month amped up its LTE network in Seoul to support blistering speeds of 300 Mbps, but the carrier is already tinkering with LTE-Advanced technologies that could double that speed in the future.

The South Korean operator is working with [company]Nokia[/company] Networks on new antenna technologies that effectively double the number of data streams sent from a cell tower to your device. Called 4×4 MIMO (multiple input-multiple output), the two companies claim they’re clocking speeds of 600 Mbps and they plan to demo the technology at Mobile World Congress in Barcelona next week.

You may already be familiar with the term MIMO because it’s a common feature in every LTE network and device today. Instead of sending a single signal from the tower, MIMO sends parallel streams, which are in turn picked up by two antennas on the device. By using four antennas instead of two at either end of the transmission, Nokia and [company]SK Telecom[/company] are able to double that capacity again.

Cool beans, right? Well, don’t get too excited.

4×4 MIMO is going to be a hard thing to pull off in a commercial network. Not only would it require device makers to pack four antennas into the limited space they have in their smartphones, but a 4×4 MIMO air link is quite delicate. When the going gets rough in today’s 4G systems, networks regularly downgrade connections from 2X2 MIMO to a single transmission path. Maintaining the proper radio frequency conditions to support a 4X4 MIMO link is going to be even more difficult, which is why the industry has been focusing its efforts on other LTE-Advanced technologies like carrier aggregation.

But I’ll be the last guy to tell SK Telecom what it can or can’t do. Ever since the dawn of 3G, SK has been on the cutting edge of wireless networking technologies, so if anyone is going to make a commercial case for 4×4 MIMO it’s probably our friendly operator in Korea. And if it works, it could be a big boon for the mobile industry because 4×4 MIMO would allow carriers to double the capacity of their networks without getting their hands on new spectrum.

SK looks to have a big presence at MWC. In addition to 4×4 MIMO demos with Nokia, SK will be showing off a very future-looking radio system with Samsung that claims to deliver 7.55 Gbps of throughput. The technology utilizes the millimeter waves, which lie higher frequencies than those used for cellular communications today. That millimeter wave technology is a big candidate for future 5G standards, though we’re still a while away from defining what exactly 5G is exactly.

AT&T tackles LTE-Broadcast at college football championship

On Monday we didn’t just see the debut of the first College Football Playoff Championship Game. We also witnessed the first appearance of AT&T’s new LTE-Broadcast technology, which uses the 4G network to send the same content to multiple devices simultaneously.

While the Oregon Ducks got crushed by the Ohio State Buckeyes at [company]AT&T[/company] Stadium at Arlington, Ma Bell used its hometown advantage to run a limited trial of the new technology. AT&T and partner [company]MobiTV[/company] broadcast two ESPN video streams from the game showing replays from different angles as well as a data stream that delivered a constantly updating feed of stats and trivia, according to FierceWireless.

AT&T sent those streams from its cellsites in and around the stadium, which network supplier [company]Ericsson[/company] upgraded for the event. But as with Verizon’s demos at the Super Bowl last year, regular AT&T customers couldn’t access them as their phones don’t yet support LTE-Broadcast technology. Instead AT&T, [company]Qualcomm[/company] and [company]Samsung[/company] rigged up a few dozen Galaxy Note 3 devices with the necessary firmware to receive the multicast signal and demoed them at the event. LTE-Broadcast, however, is part of the LTE standard so future smartphones and tablets should support the technology natively.

AT&T LTE-Broadcast graphic

So why mess around with LTE-broadcast when 4G networks are perfectly capable of delivering the same content over individual streams to today’s devices? It’s a much more efficient way to deliver high-bandwidth content to masses of people in the same place.

Consequently big events like football games are the ideal use case. Everyone wants to see the replay of that touchdown. Instead of thousand devices requesting the same content as individual streams from the same few cell towers – overloading the network in the process – the LTE-Broadcast network sends it as a single transmission. Everyone sees a high-quality video and the network uses only a fraction of its overall bandwidth.


EE’s UK network tests push LTE speeds to 410 Mbps

U.K. carrier Everything Everywhere has managed to squeeze a 410 Mbps LTE connection out of a 4G trial, generating speeds nearly 50 percent faster than its new souped-up “4G+” network in London. We’re still a couple of years away from such raw speeds in the wild, but these tests show what’s in store for consumers as the mobile industry takes up new LTE-Advanced technologies.

EE had plenty of help from [company]Qualcomm[/company], which builds the cellular modems inside of smartphones and tablets, and its network supplier Huawei. The companies supplied device and network technology that supports a new iteration of the LTE standard called Category 9, which uses a technique called carrier aggregation to bond together LTE transmissions in disparate frequency bands to create a kind of super-connection.

Many carriers around the world already have begun using carrier aggregation to tie together two LTE transmissions, but Category 9 chips will combine the bandwidth of three different frequency channels, creating a downlink up to 60 MHz wide that could potentially support speeds up to 450 Mbps. EE has already used carrier aggregation to build a 40 MHz network, but Category 9 gear is allowing it to tack on an additional 15 MHz of bandwidth in the 2.6 GHz band.

We’ll likely see other trials of the technology in the coming year, and not just in Europe and Asia. Though U.S. operators have been slow to adopt carrier aggregation, they’re deploying new 4G networks all over the frequency map. Both [company]Verizon[/company] and [company]AT&T[/company] now have second and third LTE networks in the Advanced Wireless Service and PCS bands. Meanwhile, [company]Sprint[/company] has a boatload of spectrum allocated for its new Spark 4G service. It just needs carrier aggregation to tie all of those frequencies together.