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To provide the public safety community with a better understanding of what to expect from new and emerging networking technologies, and accelerate the standardization and utilization of such technologies.


Wildland firefighter
Credit: Adobe Stock

Advances in broadband wireless technologies developed by standard developing organizations (SDOs) such as 3GPP and IEEE 802 offer unprecedented capabilities that have the potential to improve the effectiveness of first responders. Our efforts are aimed at evaluating whether or not those emerging solutions meet current public safety needs, and what improvements are necessary to meet future needs.


We provide the public safety community with the performance analysis tools needed to better understand emerging network technologies and facilitate:

  • the evaluation of worst/best case network deployment scenarios,
  • the investigation of how well new technologies support public safety requirements,
  • the development of quantitative requirements for public safety communications.
  • the development of next generation network standards in support of public safety communication needs.

Current efforts are focused on the following topic areas.

Device-to-Device (D2D) Communication

The ability for public safety personnel responding to an incident to communicate is critical to the success of the operations. In certain situations, the coverage provided by the network infrastructure (i.e. cell towers) may be missing or insufficient and therefore it is crucial for public safety devices to be able to connect directly with each other. This feature is added to LTE starting with Release 12 via the Proximity Services (ProSe). We are extending the ns-3 simulation platform to evaluate the D2D capabilities to ensure that functionalities support the public safety requirements.

Mission-Critical Communications

The situations under which first responders are communicating necessitate more stringent performance and availability requirements compare to non-emergency personnel. To enable the mission-critical communications, whether it is voice, video, or data, new architectures are proposed, such as Mission Critical Push-To-Talk (MCPTT) and Group Communication System Enablers for LTE (GCSE_LTE). In collaboration with public safety partners such as FirstNet, we are contributing to the 3GPP standard development process to ensure that the public safety requirements are clearly defined and that specifications have the potential to meet those requirements. A major focus has been on off-network MCPTT mode over LTE, where users communicate using ProSe without accessing the network. An extensive set of scenarios was created to cover most of the possible combinations of call control and floor control procedures. We have been able to verify the protocols’ correctness and provide solutions to issues identified using modeling and simulation. During our research, we evaluated the time required for users to be able to talk, also called access time, under various scenarios. We developed analytical and simulation models that provide insights regarding parameter configurations and ensure that the solutions will deliver the best possible performance for first responders. As our efforts continue, we are investigating in-coverage and partial-coverage scenarios in both LTE and 5G technologies. 

Open-source simulation tool

While we employ a variety of commercial modeling and simulation software to conduct our research, we have made extensive use of the open-source simulation tool called ns-3. Using open-source software accelerates collaboration by making it easily accessible to other researchers in both industry and academia. We have developed several public-safety oriented modules to enable simulation of ProSe and off-network MCPTT protocols. Additional models for Unmanned Arial Vehicle (UAV) energy consumption, video applications, and scenarios have also been included and released publicly ( Thanks to the Public Safety Innovation Accelerator Program (PSIAP) Funding Opportunity, we have been able to collaborate with other universities to further expend the simulation capabilities such as proper management of radio link failures, wireless backhaul, and mmWave communication.

This work is part of the Public Safety Communications Research program.


Major Accomplishments

  • Participated in 3GPP working groups (SA1, SA6, and CT1) and provided dozens of contributions regarding MCPTT and ProSe. The team received a NIST Bronze Medal in 2018 recognizing the work in the standardization of Mission Critical Voice over LTE in support of public safety communications.
  • Developed an open source modeling tool based on ns-3 simulation platform focusing on public safety operations. Main features include MCPTT application, ProSe capability, and incident scenarios.
  • Supported efforts to demonstrate the need for a dedicated nationwide spectrum for first responders and establish FirstNet.


  • R. Rouil, A. Izquierdo, M. Souryal, C. Gentile, D. Griffith, and N. Golmie, “Nationwide safety: Nationwide modeling for broadband network services,” IEEE Veh. Technol. Mag., vol. 8, no. 2, pp. 83–91, 2013.
  • D. Griffith, R. Rouil, A. Izquierdo, and N. Golmie, “Measuring the resiliency of cellular base station deployments,” in 2015 IEEE Wireless Communications and Networking Conference, WCNC 2015, 2015, pp. 1625–1630.
  • R. A. Rouil, F. J. Cintrón, A. Ben Mosbah, and S. Gamboa Quintiliani, “A Long Term Evolution (LTE) device-to-device module for ns-3,” in Workshop on ns-3 (WNS3), 2016.
  • D. Griffith and F. Lyons, “Optimizing the UE transmission probability for D2D direct discovery,” in 2016 IEEE Global Communications Conference, GLOBECOM 2016 - Proceedings, 2016.
  • J. Wang and R. Rouil, “BLER Performance Evaluation of LTE Device-to-Device Communications,” Gaithersburg, MD, USA, Nov. 2016.
  • S. Gamboa Quintiliani, F. J. Cintrón, D. W. Griffith, and R. A. Rouil, “Impact of Timing on the Proximity Services (ProSe) Synchronization Function,” in 14th Annual IEEE Consumer Communications & Networking Conference (CCNC 2017), 2017.
  • D. W. Griffith, A. Ben Mosbah, and R. A. Rouil, “Group Discovery Time in Device-to-Device (D2D) Proximity Services (ProSe) Networks,” in IEEE Conference on Computer Communications (INFOCOM 2017), 2017.
  • A. Ben Mosbah, D. Griffith, and R. Rouil, “A novel adaptive transmission algorithm for Device-to-Device Direct Discovery,” in 2017 13th International Wireless Communications and Mobile Computing Conference, IWCMC 2017, 2017, pp. 177–182.
  • R. Rouil, F. J. Cintrón, A. Ben Mosbah, and S. Gamboa, “Implementation and Validation of an LTE D2D Model for ns-3,” Work. ns-3, pp. 55–62, 2017.
  • D. W. Griffith, F. J. Cintron, and R. A. Rouil, “Physical Sidelink Control Channel (PSCCH) in Mode 2: Performance analysis,” in IEEE International Conference on Communications, 2017. 
  • J. Wang and R. Rouil, “Assessing coverage and throughput for D2D communication,” in IEEE International Conference on Communications, 2018, vol. 2018–May.
  • D. Griffith, F. Cintrón, A. Galazka, T. Hall, and R. Rouil, “Modeling and simulation analysis of the physical sidelink shared channel (PSSCH),” in IEEE International Conference on Communications, 2018.
  • A. Ben Mosbah, D. Griffith, and R. Rouil, “Enhanced transmission algorithm for dynamic device-to-device direct discovery,” in CCNC 2018 - 2018 15th IEEE Annual Consumer Communications and Networking Conference, 2018, vol. 2018–January.
  • S. Gamboa, F. J. Cintrón, D. Griffith, and R. Rouil, “Adaptive synchronization reference selection for out-of-coverage proximity services,” in IEEE International Symposium on Personal, Indoor and Mobile Radio Communications, PIMRC, 2018, vol. 2017–October.
  • R. Rouil, W. Garey, C. Gentile, N. Golmie, and P. Schwinghammer, “Increasing public safety broadband network resiliency through traffic control,” Digit. Commun. Networks, vol. 4, no. 1, 2018.
  • F. J. Cintron, “Performance evaluation of LTE device-to-device out-of-coverage communication with frequency hopping resource scheduling,” 2018.
  • P. Varin, Y. Sun, and W. Garey, “NISTIR 8236 Test Scenarios for Mission Critical Push-To-Talk (MCPTT) Off-Network Mode Protocols Implementation,” 2018.
  • D. Griffith and A. Ben Mosbah, “On Upper Bounds for D2D Group Size,” 2019 IEEE Global Communications Conference (GLOBECOM), Waikoloa, HI, USA, 2019, pp. 1-6.
  • Y. Sun, W. Garey, R.A. Rouil, and P. Varin, “Access Time Analysis of MCPTT Off-Network Mode over LTE,” Wireless Communications and Mobile Computing, Volume 2019, Article ID 2729370, 19 pages,
  • J. Wang, R. A. Rouil and F. J. Cintron, “Distributed Resource Allocation Schemes for Out-of-Coverage D2D Communications,” 2019 IEEE Global Communications Conference (GLOBECOM), Waikoloa, HI, USA, 2019, pp. 1-7.
  • C. Liu, C. Shen, J. Chuang, R. A. Rouil and H. Choi, "Throughput Analysis between Unicast and MBSFN from Link Level to System Level," 2019 IEEE 90th Vehicular Technology Conference (VTC2019-Fall), Honolulu, HI, USA, 2019, pp. 1-7.
  • S. Gamboa, R. Thanigaivel and R. Rouil, "System Level Evaluation of UE-to-Network Relays in D2D-Enabled LTE Networks," 2019 IEEE 24th International Workshop on Computer Aided Modeling and Design of Communication Links and Networks (CAMAD), Limassol, Cyprus, 2019, pp. 1-7.
  • S. Gamboa, A. Moreaux, D. Griffith and R. Rouil, "UE-to-Network Relay Discovery in ProSe-enabled LTE Networks," in proceedings of 2020 International Conference on Computing, Networking and Communications (ICNC), Big Island, HI, USA, 2020.
Created April 30, 2009, Updated April 14, 2020