EM9191 - bogus AT!GSTATUS / !NRINFO output for MIMO streams

When connected and active, AT!GTATUS and AT!NRINFO report:

NR5G band:       n78                    NR5G Carrier ID: 0
NR5G dl bw:      90 MHz                 NR5G ul bw:      90 MHz    
NR5G Tx Power:   21                     NR5G Tx chan:    643666
NR5G Rx chan:    643666
NR5G dl MIMO:    0                      NR5G ul MIMO:    1
NR5G(sub6) RxM RSSI (dBm):   -62.5      NR5G(sub6) RxD RSSI (dBm):   -46.6
NR5G(sub6) RxM1 RSSI (dBm):  -59.8      NR5G(sub6) RxD1 RSSI (dBm):  -46.0

When inactive, both DL and UL MIMO report “0”.

According to the AT command reference, the line contains:

NR5G dl MIMO: <dlMaxMimo> NR5G ul MIMO: <ulMaxMimo>

Why does it always report “0” for the DL, this should be 4 apparently. And what is “0” supposed to mean?

Hi @stefanbruens

Have you tried with the latest FW from https://source.sierrawireless.com/resources/airprime/software/em919x/em9-approved-fw-packages? Are you on a data call when you see the issue? ENDC or SA?

I said “connected and active” - so yes, this is while transmitting data.
In idle mode, the output is even more broken.

If there are any differences in the output between RRC ACTIVE and IDLE, this should both be mentioned in the documentation. But the current values makes not sense, for neither RRC state.

All this has been tested for 03.09.06, 03.09.03, and various earlier versions.

hmm, we’d fixed quite a few issues with these commands in the latest FW.

We can’t debug this issue in the forum. Please open a support case with us. Please provide details about what you expect to get vs what you get and DM logs that capture the modem attach process. Please use the Default.cfg
Default.cfg (3.9 KB). It’s also available in MBPL: Tools\dm-logger\filters.

  • AT+CFUN=0
  • Start DM logging with Default.cfg
  • AT+CFUN=1
  • Start Data
  • Reproduce the issue
  • Stop DM logging.

Provide the DM logs, AT logs, description etc in the case. More information you provide the better :slight_smile:

This is already with the latest release FW version, 03.09.06. But I already mentioned that.

What are the dl MIMO /ul MIMO fields supposed to show? You don’t need a reproducer to answer this question.

And in case you want to reproduce it, quoting from the AT command reference, rev. 4 (latest):

NR5G Cell ID:  500 
NR5G band:     n77       NR5G Carrier ID: 0 
NR5G dl bw:    20 MHz    NR5G ul bw: 20 MHz 
NR5G Tx Power: -22       NR5G Tx chan: 620644 
NR5G Rx chan:  620644 
NR5G dl MIMO:  0         NR5G ul MIMO: 1 
NR5G(sub6) RxM RSSI (dBm):  -31.8   NR5G(sub6) RxD RSSI (dBm): -5.6 
NR5G(sub6) RxM1 RSSI (dBm): -37.9   NR5G(sub6) RxD1 RSSI (dBm): -4.4

So you can reproduce this on your own, obviously.

dlMaxMimo and ulMaxMimo are the maximum number of MIMO layers as per service cell configuration. For DL, it’s the maximum number of layers the UE can expect from the NW on PDSCH. If you are seeing a 0 for the DL, it could be that the NW hasn’t configured it. You can assume the UE’s maximum in that case. Hope this helps.