Could a third transmit antenna be the key to higher 5G uplink speeds?

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Samsung partnered with MediaTek to complete a 5G standalone (SA) uplink trial that echoed previous work by U.S. operators and silicon providers, but added another uplink antenna connection to the mix to try to further spike performance.

The Samsung and MediaTek test was conducted in a lab in South Korea. It used Samsung’s C-band massive multiple input, multiple output (MIMO) radios, virtualized distributed unit (vDU) and 5G SA core technology. These were linked to a MediaTek-powered test device that connected through separate uplink channels in the 1.9 GHz and 3.7 GHz bands, with an extra link using MIMO in the 3.7 GHz band.

This concoction resulted in a peak uplink speed of 363 Mb/s. The partners admitted that current smartphones and customer premises equipment (CPE) only support two transmit antennas, but that the test shows the potential for performance improvement if those devices eventually gain three-antenna support.

T-Mobile US, AT&T and Verizon earlier this year all touted similar uplink tests that showed similar performance improvements.

T-Mobile’s test was conducted with Nokia and Qualcomm, where they managed to aggregate two different spectrum bands in support of an uplink speed in excess of 200 Mb/s running across T-Mobile’s “live commercial” 5G SA network. A T-Mobile spokesperson explained to SDxCentral that the test merged 20 megahertz of spectrum in the 1.9 GHz band and 100 megahertz in the 2.5 GHz band to produce an uplink speed of 207 Mb/s.

The carrier also stated that customers with compatible devices would be able to take advantage of the uplink enhancement beginning early next year.

AT&T’s efforts were with Nokia and MediaTek, where they aggregated varying amounts of spectrum running on AT&T’s 5G SA core. With 10 megahertz of AT&T’s low-band 850 MHz spectrum and 40 megahertz of C-band spectrum, they were able to generated 70 Mb/s of uplink speed, with speeds increasing to 120 Mb/s when using 100 megahertz of C-band spectrum.

Verizon’s uplink push aggregated 20 megahertz of “LTE” spectrum and 400 megahertz of 28 GHz spectrum that resulted in upload speeds up to 1.26 Gb/s. Those speeds were registered using commercially available devices in a live network environment.

Uplink speeds in wireless networks often trail that of downlink speeds. This is most often due to the power requirements needed to beam a spectrum-heavy connection between a device and base station. Most end-user devices obviously have a smaller form factor than a cell tower so they need more creative antenna technology to support the signal. The devices also often rely on an embedded battery, which can quickly heat up and drain while trying to power that connection.

This discrepancy was made clear in Opensignal’s recent 5G Experience Report, which showed 5G download speeds ranging between 80 Mb/s and more than 195 Mb/s, while upload speeds were between 12 Mb/s and 19 Mb/s.

However, analysts have noted that wireless uplink speeds are becoming increasingly important for both consumer and enterprise customers.

Consumer space demand is being driven by the growth in end user–generated video content that is often created or streamed from a mobile device and is uploaded from that device to social media platforms across a cellular connection.

“As mobile internet trends move away from downloading content to creating content and supporting real-time communications services, upload speeds are becoming more vital and new technologies are emerging that boost upstream capacity,” Opensignal noted in its report.

European-based telecom operators like Telefónica have used this challenge to argue for “fair share” contributions from “large traffic generators.”

Operators are also looking to boost uplink speeds in order to better penetrate the lucrative enterprise market with services like 5G-powered SD-WAN and private 5G networks. This can also play into the eventual use of 5G-based cellular connections to power extended reality (XR) devices and services.

“With demands on mobile networks rising, enhancing upload performance is essential to improving consumer and enterprise connectivity, as well as application experiences,” Will Townsend, VP and principal analyst at Moor Insights and Strategy, noted in a statement tied to the latest Samsung test.