From my understanding (source), they use a trunked radio system used by the station. Best I can tell, it is likely a leased NexEDGE system that covers that portion of the state. Beyond that I don't know...
If they are they they're on their own system because the paragould system I quoted is analog only, However if it's their own system I didn't find any license for them in the FCC Database, however I did find that Radio Communications has a trunk system in Jonesboro and it's licensed for NXDN so there's a possibility too. I don't know for sure but I'll see what I can find out.