How to configure MIMO on EM9291?

IoT Modules MC/EM Series
1

Can I configure the EM9291 to run in 2x2 MIMO mode in both LTE and 5GNR? Is it band specific? It seems to be in 4DL x 2UL mode right now.

2

you need to use FW 03.04.10.00 afterwards.

In addition, you also need to configure AT!RFCID.

BTW, you need to contact distributor to get a new application note for “EM92 2-Antenna Operation”

4

This is what I have:

at!verinfo

Firmware ID: 6CE998

Boot Loader: SWIX65C_02.13.08.00

   TAOP: 93F895

  Modem: SWIX65C_02.13.08.00

   Apps: SWIX65C_02.13.08.00

I found the firmware download page (https://source.sierrawireless.com/resources/airprime/software/em929x/em92-approved-fw-packages/#sthash.VYrw8xh6.dpbs ), but it only has firmware up to 2.17 for Generic. I assume I need Generic since this is for a lab test (PLMN 00101). The only one that had 3.04 is for “PTCRB”. what is that? Should I use that one for my lab testing instead?

Thanks.

5

Ptcrb is for regulation certification in US
You can try that one.

Did you contact distributor to get a new application note for “EM92 2-Antenna Operation”?

6

I don’t have a distributor since I got mine through Digikey.

I did a quick google search and found “EM929X Hardware Integration Guide” 41114769 Rev. 3 - is that what you mean?

7

no, that is not same document…
then you need to see if there is support channel from Digikey.

BTW, what is the SKU of your module?


AT!ENTERCND="A710"
AT!SKU?
8

SKU is 1105097

Digikey is just a catalog, no support. I tried going to the Sierra Wireless support page and it only has a very unhelpful chatbot. The chatbot doesn’t even have an option to ask about EM9291 (only EM9191 was a choice). I tried asking for the app note but there wasn’t an option for that. I’ll try finding a support email address to ask for the app note.

9

For your module with SKU 1105097, you can try the following on 2 antenna option with the FW 03.04.10.01 afterwards :

AT!ENTERCND="A710"
at!rfcid=1000,,,,3
at!reset
10

OK, thanks! Once I get a break in testing, I’ll try upgrading the firmware to 3.04.10.01 and issuing that command.

What antenna ports are activated for TX/RX if I change it to 2x2 MIMO? Looking at Table 3-2: 5G NR Sub-6 GHz / LTE/WCDMA / GNSS Antenna Receptacles—RF Technology Support in the Hardware integration guide, the default TX ports change by RAT and by band which makes it confusing when running tests in different channels.

For example for 5G n38, n41 the default TX is ANT2 and alternate is ANT0. But for LTE B41 the default TX is ANT0 and alternate is ANT2.

Does this mean if I go to 2x2 MIMO for n41 or B41, I’d just connect ANT2 and ANT0?

11

for two antenna mode, only ANT0 and ATN2 are supported

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