MU-MIMO and the Tower of Power (Chapter 2)

06/26/2023 | 62 pages
Price: $1,750.00

SRG just completed its 33rd 5G benchmark study.  For this endeavor we collaborated with Accuver Americas and Spirent Communications to conduct an independent benchmark study of 5G MU-MIMO, using Verizon’s commercial 5G network in Memphis, TN, where Samsung is the RAN infrastructure supplier.

Highlights of the Report include the following:

Our Thanks.  We did this study in collaboration with Accuver Americas (XCAL5 and XCAP) and Spirent Communications (Umetrix Data).  SRG is responsible for the data collection and all analysis and commentary provided in this report.

Our Methodology.  We primarily tested at one cell site (3 sectors) which supported MU-MIMO, 100 MHz channel bandwidth (versus the typical 60 MHz that VZ has deployed), and 10 Gbps backhaul.  We did stationary testing with four Galaxy S22 smartphones placed in vehicles in various locations within the sector and included 2 different drive test routes to gauge the impact of mobility on MU-MIMO and SRS performance.  We estimate ~15 different device placements with stationary tests.

Key Differences.  To our surprise, the virtualized RAN (vRAN) supported 16 downlink MIMO layers and 8 uplink MIMO layers.  We didn’t realize this capability until after we started analyzing the results in detail.  We didn’t test uplink MU-MIMO while with only 4 smartphones, the results we obtained likely understate the full MU-MIMO potential of the network.

The Results are In.  Without getting into specifics, we observed near-perfect reuse of network resources (RBs) in most tests.  Additionally, the aggregate MIMO layer count was frequently close to 8 layers across all smartphones after adjusting for RB use/reuse, and reaching at least 12 layers in some cases.  Although MCS dropped in most tests, the net effect was still up to a high double-digit increase in sector capacity.  The results with devices placed close together wasn’t what we were hoping for since the sharp drop in MCS more than offset the high RB reuse and higher total MIMO layer count versus SU-MIMO.

FWA.  FWA is THE use case for MU-MIMO.  In addition to the need for increased low-cost capacity due to the usage profile of FWA, FWA benefits from relying on stationary devices (CPEs), which generally tends to result in better MU-MIMO results.