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Evaluation of Timers Related to ProSe-based UE-to-Network Relays



Aziza Ben Mosbah, Samantha Gamboa Quintiliani, Richard A. Rouil


User Equipment (UE)-to-Network Relay functionality was introduced in Release 13 of the Third Generation Partnership Project (3GPP) Long Term Evolution (LTE) to extend and improve user connectivity using the sidelink (SL) channels. The UE-to-Network Relay signalling allows the establishment and maintenance of a direct connection between the relay UE and the remote UE. Different procedures and timers are linked to these processes. In this paper, we focus on describing and evaluating the PC5 Signalling Protocol performance through system-level simulations. We also propose recommended timer values to increase the probability of successfully establishing and maintaining the connection between a remote UE and a relay UE.
Technical Note (NIST TN) - 2144
Report Number


3GPP, ProSe, LTE, relay, remote, device-to-device communication, protocols, proximity-based services, ns-3


Ben, A. , Gamboa, S. and Rouil, R. (2021), Evaluation of Timers Related to ProSe-based UE-to-Network Relays, Technical Note (NIST TN), National Institute of Standards and Technology, Gaithersburg, MD, [online],, (Accessed July 23, 2024)


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Created March 24, 2021, Updated April 6, 2021