The Public Safety Communications Research (PSCR) program executes network modeling and simulation analysis on Long Term Evolution (LTE) technology performance for mission critical scenarios in a nationwide, interoperable public safety broadband network. PSCR is developing communications and network models that provide valuable information during the early phase of network planning, including: data on the network, feature performance, and analysis of potential network architecture and site locations.
The Middle Class Tax Relief and Job Creation Act of 2012 (H.R. 3630) appropriated $7 billion for the establishment of a nationwide interoperable public safety broadband network (PSBN) under FirstNet, an independent authority in the National Telecommunications and Information Administration (NTIA). FirstNet will provide first responders with dedicated and prioritized access to high-speed data, voice, and other mission critical applications. This nationwide network will enable public safety agencies at the federal, state, and local levels to effectively conduct their mission by establishing a common communications system based on 3GPP LTE standards.
Although cellular communications have existed commercially for years, this nationwide public safety broadband network will be the first of its kind. PSCR and the Wireless Networks Division at NIST, in partnership with the Department of Homeland Security (DHS) Office for Interoperability and Compatibility (OIC) and FirstNet, are developing network modeling and simulation metrics and tools to ensure that the network is efficient and meets public safety’s needs. Modeling and simulation are generally used in the planning and design of networks before deployment, to assess the performance of features and capabilities not yet implemented in products, and to investigate network scalability.
CTL’s Wireless Network Division conducts performance analyses of advanced communication networks for PSCR using commercially available and in-house customized network modeling and simulation tools. In support of the nationwide public safety broadband network, the division develops the metrics and tools for characterizing the performance of LTE in support of public safety communications. These tools are then used to:
• Evaluate the performance of LTE key features and capabilities such as proximity services, quality of service, priorities, and pre-emption
• Provide insights on the performance trends and trade-offs in order to identify the key factors and configuration parameters that affect network performance, reliability, and resiliency
• Define common performance metrics and a modeling approach to facilitate comparisons of network scenarios and deployments
The major performance metrics focus on the coverage provided by the network over a target geographic area and the capacity of the network in terms of the number of public safety users accessing the network. In order to obtain these metrics, the group uses existing network models and when necessary develops new models of radio frequency interference, propagation, and algorithms that improve spectral efficiency.
Public safety’s ability to evaluate different models of the nationwide public safety broadband network will help inform a network build out that is efficient, effective, and meets public safety’s unique requirements. Leveraging these modeling and simulation tools will help public safety and the public safety network operator identify opportunities for cost savings and have realistic expectations of network coverage, capacity, and performance.