On the streets of Suwon, South Korea, Sprint and Samsung Electronics America, Inc. recently tested Massive MIMO (multiple input, multiple output) on 2.5 GHz spectrum. The Massive MIMO test represented a real-world application of the new technology, slated to help Sprint dramatically boost LTE Plus wireless capacity and coverage, and offer Gigabit LTE service to its customers.

“The testing in South Korea is an important step towards deploying Massive MIMO in our U.S. network where it will be a key element of LTE Plus as well as 5G,” said Günther Ottendorfer, Chief Operating Officer – Technology, at Sprint. “Massive MIMO is a tremendous differentiator for Sprint because it is easily deployed on 2.5 GHz spectrum due to the small form factor of the radios needed for a high frequency band. In lower frequency bands, wavelengths are much longer and therefore the radios require much larger, impractical form factors. This makes Massive MIMO an important tool for unleashing our deep 2.5 GHz spectrum holdings.”

From left to right, Günther Ottendorfer, Sprint COO – Technology, Ryan Sullivan, Sprint VP Product Engineering and CH Kim, Samsung SVP Research and Development. They are standing with the 2.5GHz 64T64R AAU (Active Antenna Unit) that enables FD-MIMO (or Massive MIMO) technology. 

During field testing in Suwon, Massive MIMO Samsung radios, equipped with vertical and horizontal beam-forming technology, reached peak speeds of 330 Mbps per channel using a 20 MHz channel of 2.5 GHz spectrum. Capacity per channel increased about four times, cell edge performance increased three times, and overall coverage area improved as compared to current radios.

Sprint has deployed 8T8R (8 transmit, 8 receive) radios across its U.S. network, and the purpose of the test was to compare the performance of Massive MIMO radios with 8T8R radios. Sprint, in collaboration with Samsung wrote the test cases and requirements, which included a variety of performance scenarios involving multi-user and non-stationary testing. Samsung provided the Massive MIMO network infrastructure as well as test network design, operation, data collection and processing. Both companies will use the results in preparation for commercial deployment of Massive MIMO in the U.S. and other markets.

“Our recent testing in Suwon delivered impressive capacity and coverage improvements in a real world environment, demonstrating how massive MIMO will greatly improve a customer’s wireless service experience,” said Mark Louison, Senior VP and General Manager of Samsung Networks. “Samsung is excited to reach this important milestone with Sprint, as we continue to develop the commercial solution for the coming year that is expected to provide nearly 8x capacity improvements. This is another innovation Samsung will deliver to our technology-forward customers who operate some of the most data-intensive networks in the world.”

Gigabit Speed with Massive MIMO

Massive MIMO radios use more antenna elements. For example, 64T64R (64 transmit, 64 receive) uses 128 antenna elements, whereas 2T2R/4T4R/8T8R is used in a typical 4G LTE network today. These Massive MIMO antennas use advanced horizontal and vertical beamforming technology to focus and transmit cellular signals into targeted locations. This more efficient use of spectrum delivers faster speeds and provides more data capacity to customers in high-traffic locations. When deployed on the network, Massive MIMO can provide all mobile device users with performance improvements, and those with the latest generation of devices with the most antenna elements will see the best performance. Massive MIMO, a key element of 5G slated to provide high capacity in densely populated urban centers, can enable LTE network performance well beyond 1 Gbps.

In cities across the U.S., Sprint plans to deploy Massive MIMO radios with 128 antenna elements (64T64R) using its 2.5 GHz spectrum to increase capacity up to eight times. In March, Sprint was the first U.S. carrier to debut Gigabit Class LTE on a live commercial network in New Orleans. There Sprint used three-channel carrier aggregation and 60 MHz of 2.5 GHz spectrum, in combination with 4X4 MIMO and 256-QAM higher order modulation, to achieve Category 16 LTE download data speeds on a TDD network. With Massive MIMO radios using 64T64R, Sprint has the ability to push capacity beyond 1 Gbps to reach 3-6 Gbps per sector.

source: Sprint