Evaluation of TETRA SDS Performance and GPS Accuracy in Real-World Scenarios

Terrestrial Trunked Radio (TETRA) is a communication system for public safety featuring voice, Short-Data-Service (SDS), e.g., for GPS updates, and data communications. This paper presents measurement results concerning GPS accuracy and SDS performance of several real-world scenarios using TETRA in trunked mode. In particular, we considered intra-cell communication, inter-cell communication, and stationary as well as mobile use cases. Besides lab settings, we also performed two different field tests of semi-realistic and realistic first responder drills. SDS delay was satisfactory in all scenarios but GPS accuracy of common TETRA handheld radios turned out to be limited, especially compared with current Android devices. This is yet another argument in favor of complementing the use of TETRA with other broadband technologies like LTE/5G, which would then not only enable multimedia communications but also give access to more accurate positioning.