UL MIMO analysis in LML and LMA

UL MIMO analysis in LML and LMA

As the lifecycle of 5G marches onwards, UL MIMO will continue to show up in locations around the country, necessitating more and more testing. To facilitate this testing, there are a variety of ways to analyze UL MIMO using both Link Master Logging (LML) and Link Master Analysis (LMA).

In LML, a variety of real time PUSCH statistics are available in the NR 5G CA Status Monitor, including three with relevance to UL MIMO. The PUSCH MIMO field reports the the dominant MIMO mode used during the last second, the PUSCH Layer field refers the most common layer count during the last second (L1 or L2 MIMO), and PUSCH Layer [%] reports the percentage of packets sent using [L1 / L2] MIMO in the last second. For example, this screenshot shows a UE using 2x2 (SMDL) MIMO with 60% layer 2 and 40% layer 1 usage during the previous second.


To investigate the MIMO breakdown further, load the log file into LMA and navigate to NR5G>PCC>MAC>UL Physical Channel, where you can see exactly how many packets were transmitted using each MIMO method every second using the Num of SISO/SMSL/SMDL parameters.


Additionally, the nearby NR5G>PCC>PUSCH>MIMO lets you see more information about what type of MIMO was used over the component carrier, including a breakdown of the MIMO usage of each TX antenna. The Num of Layer (Avg) parameter is also useful, as it calculates the average number of layer used each second, producing a value between 1.00 and 2.00. For example, at index 50, 83.33% of the packets were L1 and 16.67% of the packets were L2, so the Num of Layer (Avg) was 1.17.


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