T-Mobile's 5G network capacity gained with MU-MIMO

SRG analysts conducted tests of T-Mobile's 2.5 GHz network in Southern California, where Ericsson is the infrastructure supplier. Their conclusions show a significant capacity increase (over 50%) in the presence of MU-MIMO compared to single-user MIMO, also known as SU-MIMO. This is especially relevant for his Fixed Wireless Access (FWA) business at T-Mobile.

For SRG`s tests, T-Mobile furnished logistical assist, consisting of phones, SIMs and steering on wherein to discover a massive cluster of cells helping MU-MIMO with 10 Gbps backhaul. Neither T-Mobile nor Ericsson furnished economic assist for the study. The analysts used industrial smartphones OnePlus 10 Pro and the Samsung Galaxy S22, in addition to pre-industrial CPEs from Arcadyan. Spirent Communications and Accuver Americas furnished take a look at and size tools.

SRG President and founder Mike Thelander said his company gave T-Mobile and Ericsson a brief presentation ahead of the report's release, noting that T-Mobile has MU-MIMO capabilities nationwide. , revealed that the Sounding Reference Signal (SRS) Technology is implemented. I am using Ericsson equipment. There are plans to roll out similar functionality on Nokia 2.5GHz sites by mid-2023. He pointed out that not all smartphones support his SRS, but SRG believes the feature is present on the carrier FWA CPE and at least on certain of his iPhone models.

Last year, Thelander encountered MU-MIMO in the Verizon band n77 (C-band) Ericsson network in Minneapolis. Verizon confirmed to SRG that it is evaluating the technology, Thelander said. “There’s clearly interest from all operators. I don’t know where Verizon’s at in terms of deploying it” or testing it, he said. Both T-Mobile and Verizon use Ericsson and Nokia 5G gear; Verizon also uses Samsung. 

“If an operator can increase their network capacity by 50% through a basic software upgrade, that’s a no brainer,” he said. “That’s why it’s so compelling.”

There are different ways of implementing MU-MIMO. What Ericsson is doing is based on technology called SRS and Thelander equated it to a game of Marco Polo in a swimming pool.

“This is a similar concept whereby the phone is transmitting signals in the uplink. Those signals allow the base station to figure out where that mobile phone is,” and it can precisely send data to it and use the same resource block to send data to another phone, he said. It works best in a low-mobility situation, which is where FWA operates.

SRG included some insights based on its observations while testing and analyzing the study results that are unrelated to MU-MIMO. “The Reader’s Digest version is that T-Mobile is currently evaluating a new configuration for its TDD frame structure which will allow it to increase downlink capacity/downlink data speeds,” the report notes.

Thelander also explained the meaning behind the illustration on the cover of the MU-MIMO report. It shows a Spider-Man character shooting signal beams aimed at Doctor Octopus, who has four “arms” and each one is holding a phone. Two beams of light are coming from the base station to each phone, and these beams represent data streams, tallying up to eight.

With SU-MIMO, each network resource can be re-used up to four times. The terms “4x4 MIMO” and “4-layer MIMO” refer to one network resource being re-used four times, and there’s a theoretical quadrupling of the throughput over a single network resource, he said.

MU-MIMO is conceptually similar to SU-MIMO, but “the difference is that one network resource can be shared by multiple phones,” he said, theoretically allowing eight phones to share the same network resource at the same time. I added that you can connect to different phones with This effectively doubles the capacity of the network, making capacity critical when it comes to FWA. Both T-Mobile and Verizon claim they are taking steps to ensure that his FWA users, who on average use more data than their cellphone customers, don't run out of capacity. But the question of capacity and how much we can deliver comes up again and again. Especially when there isn't much mid-band 5G spectrum in the pipeline, it's no surprise that carriers are at their disposal to use whatever tools they can to increase capacity. "For things like fixed wireless access, which consumes a lot of data, it's a great way for operators to increase the overall capacity of their networks," said Thelander.