A friend sent me a link to an interesting blog post talking about making an Open-Source DMR radio using a LimeSDR board and GNU Radio.
Digital Mobile Radio (DMR) is a mobile radio standard created by ETSI, which is very popular within the amateur radio community. […]
A very basic DMR modem (receiver and transmitter), capable of voice calls, that could emulate a subscriber radio using a SDR transceiver as the radio interface is described in this page.
While this modem is just a proof-of-concept interpretation of the DMR standard with no real use-case, there exists at least one open source project which proposes to create an open source DMR transceiver.
You can see the full blog post over there: https://qradiolink.org/open-source-DMR-transceiver-implementation.html