Sprint and Ericsson are promising to demonstrate Gigabit LTE using 60 megahertz of LTE TDD spectrum when the industry convenes in Barcelona, Spain, for Mobile World Congress 2017 next week.
That’s a lot of spectrum, but it’s exactly the same that Sprint is using for its 3-channel carrier aggregation (CA) in the United States, where it has 160 megahertz of 2.5 GHz (Band 41) spectrum in the top 100 markets. The Gigabit LTE TDD demo in Spain also will feature Ericsson’s LTE Advanced features, including 4x4 MIMO, high order modulation (256 QAM) and Ericsson Lean Carrier.
Sprint is unique in the U.S. market in its use of TDD, where the transmit and receive is done on the same frequency channel. Most of the spectrum allocated in the United States is FDD, which uses paired spectrum so the transmit is done on one spectrum band and the receive on another.
FDD came along in the old days when the industry was more voice-centric and people talked as much as they listened, but it’s not really conducive for data, said Sprint CTO John Saw. Most data-centric formats today, like Wi-Fi, Bluetooth and ZigBee, use TDD because it’s more data-friendly.
Standards for 5G are still being developed, but early rumblings indicate TDD is the preferred format, although to promote flexible use—i.e., let operators choose what they want to use—it’s likely both TDD and FDD will be supported in 5G. TDD-LTE represents one of the world’s largest LTE ecosystems, Saw noted.
With TDD, Sprint can adjust its spectrum allocations depending on customer usage behavior, he said. The operator knows that its customers download six to eight times more than they upload, so it can make more spectrum available on the downlink for that purpose.
In December, Sprint announced High Performance User Equipment (HPUE), a breakthrough for TDD-LTE operators like Sprint, China Mobile and SoftBank, among others. HPUE has the ability to extend Sprint’s 2.5 GHz coverage by up to 30%, including indoors where the majority of wireless traffic is generated. Samsung is expected to support HPUE in devices slated for commercial launch in 2017, but other handset makers are expected to announce support for it next week.
Ericsson is not the only vendor hooking up with Sprint next week. Nokia has said it will work with Sprint at the show to demonstrate AirScale massive MIMO Adaptive Antenna using 3D beamforming software to deliver throughput gains of up to eightfold uplink and fivefold downlink. The demonstration will leverage commercially-available devices operating on TD-LTE Band 41.
Besides participating in Sprint’s demos, Saw said he’ll be attending MWC to meet with vendors and learn more about their product road maps as well as see what new companies are offering by way of improving the customer experience with things like massive MIMO and Gigabit LTE. “These are all essentially stepping stones toward the 5G network,” he said.