Activating MIMO

I’d like to test the MIMO capability of the LimeSDR. I currently am using LimeSuite to generate all my simple CW carrier signals. I’d like to activate the second transceiver simultaneously for a few transmit tests.

Anyone know how to set that up in LimeSuite? I’ve turned on MIMO support, but am unsure how to address the second transceiver. I tried selecting Channel B in the interface but that didn’t seem to work.

I did a bit more testing and this appears to work:

In LimeSuite, select Channel A or Channel B for TX1-1/2 or TX2-1/2

Then select TRF and use Band 1 or Band 2 from the drop down to select either TX1-1/TX1-2 or TX2-1/TX2-2 on either channel.

I’m still looking to figure out how to transmit different frequencies on each transceiver.

You can transmitt simultaneously on different frequencies only if they are not more than 60 MHz appart.

Understood. I was trying to test 10 MHz apart, but can’t see how to make that happen. Even when I select Channel A or B and SXT, they all transmit on the same frequency…

I’m missing something in LimeSuite…

If you are using limesuite try going to the TxTSP page and set the offset frequency in the (FCW) table select the one you want to offset then upload the NCO table to the device. It is the Transmit Signal Processor that does the offset.

  • Charles


That worked! But it appears to add another signal offset +/- from the fundamental. So if MIMO is on and SXT is set to 500 MHz, I get 500 MHz on both transceivers. If I offset either channel A or B 5 MHz in TxTSP, I get signals on that channel at 495/500/505 MHz.

I need to play some more.


I suspect you will need to calibrate for IQ gain/phase errors as I think what you are seeing is the
unwanted image due to imbalance (the bane of zero IF radios).

  • Charles

It was IQ imbalance. That cancelled the lower signal just fine. Now to figure out how to get just the offset frequency.

Tnx Charles.