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Bridging Analog LMR to LTE MCPTT Communications



Christopher J. Walton, Chic J. O'Dell


This paper explores a low-cost method to bridge analog public safety Land mobile radio (LMR) systems into a standards based Long Term Evolution (LTE) MCPTT system. Design goals included robustness, cost, and the creation of a system that closely conforms to released and future standards. A proof of concept prototype that successfully bridges an analog LMR system with a standards compliant LTE based MCPTT system was developed and tested. The results and design details will be covered in this paper.
NIST Interagency/Internal Report (NISTIR) - 8338
Report Number


Digital Fixed Station Interface (DFSI), InterWorking Function (IWF), Inter-RF Subsystem Interface (ISSI), Land mobile radio (LMR), Long Term Evolution (LTE), Mission Critical Push to Talk (MCPTT), Over the Air (OTA), Push-to-talk (PTT), Radio over IP (RoIP), Software Defined Radio (SDR), Subscriber Unit (SU), User Equipment (UE)


Walton, C. and O'Dell, C. (2020), Bridging Analog LMR to LTE MCPTT Communications, NIST Interagency/Internal Report (NISTIR), National Institute of Standards and Technology, Gaithersburg, MD, [online], (Accessed April 23, 2024)
Created December 17, 2020, Updated December 18, 2020