As my final year project at university, I have successfully configured the LimeSDR-USBv1.4 to work as an RFID reader of standard commercial UHF RFID tags. Thanks to all those on this forum who helped me with some of the issues I encountered along the way.
SoapySDR was used with SoapyUHD, in order to use standard UHD blocks in a GNU Radio application. I ended up having to edit the SoapyLMS7 drivers in order to resolve a few problems. I have uploaded my edited version of the drivers to a github repo here, along with my GNU Radio application. Further details of my implementation can be found in the readme.
I wrote up my findings in a final report, which is also included in the repo. The report includes some relevant background, along with a discussion of the problems encountered, the solutions implemented, and an evaluation of the LimeSDR’s performance as an RFID reader. Warning: the report is almost 50 pages long!
I no longer have access to the LimeSDR or any of the relevant equipment so I won’t be able to develop the code further; I am however happy to answer any questions that people may have.
I hope people find the above useful.
Disclaimer: I was (and still am) very much a beginner at SDR in general, let alone the LimeSDR specifically. It is possible that there are therefore mistakes in my implementation, conclusions, and/or analysis - if you spot any, please post them here in order to help others!