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Public Safety Communications Research


The primary objective of the Public Safety Communications Research program is to lead the development of wireless telecommunications and information technology standards, profiles, and guidelines for interoperability, and information sharing, among criminal justice (CJ) and public safety (PS) agencies at state, local, and federal levels. To achieve this it will be necessary to focus on enabling technologies and open architecture standards so that interoperability approaches can be designed and implemented. Proposed techniques and standardized configurations will be verified and validated through simulations and laboratory testing. While standards are being developed, other interim interoperability solutions will be investigated. As a secondary goal, this project will conduct technical evaluations of current and emerging technologies aimed at providing immediate assistance to CJ and PS agencies.


Too often in critical situations communications the data exchanges between law enforcement and public safety agencies are hampered by equipment incompatibilities. In large part these incompatibilities are due to a lack of standards to provide a common, nationwide approach to telecommunications and information sharing. The Department of Homeland Security's Wireless Public SAFEty Interoperable COMmunications program (SAFECOM), the umbrella initiative to coordinate all Federal, state, local, and Tribal users to achieve national wireless communications interoperability and the Department of Justice's Community Oriented Policing Services (COPS) have a common goal to resolve these issues by supporting the development and implementation of communications standards that will advance communications interoperability.

The OLES Public Safety Communications Systems program provides technical support to both of these programs. The OLES program, drawing on existing standards as well as critical requirements provided by public safety practitioners, provides insight and direction to IT and wireless standards committees that are developing standards for voice, data, image, and video communications. To meet the short term needs of law enforcement and public safety agencies until such standards are in place, the program also evaluates commercial devices that can provide for interim interoperability.

Major Accomplishments

OLES representatives hold the following leadership positions in Project 25 related task groups/committees or other organizations:

  • Vice-Chair of the ISSI Task Group
  • Vice-Chair of the P25 Systems Architecture Working Group (PSAWG)
  • Vice-Chair of the Vocoder Task Group
  • Vice-Chair of the Compliance Assessment Process and Procedures Task Group
  • Chair of the APCO 25 Interface Committee Broadband Task Group
  • Vice-Chair of the Technology Committee in the National Public Safety Communications Working Group
  • Co-Chair of the Broadband Interoperability Working Group in NPSTC
  • Chair of the Security Working Group in NPSTC
  • Chair of the VoIP Working Group in NPSTC
  • Chair of the Technical Systems Group in Project MESA

Provided technical support for SAFECOM's first Voice over IP (VoIP) Industry Roundtable to address the growing problem of the increasing number of incompatible IP-based interoperability gateways. Representatives from public safety VoIP vendors such as Motorola, EADS, MACOM, Twisted Pair, Cisco, Catalyst and public safety representatives from APCO, IACP, FPS were in attendance. A key outcome of this event was a commitment to consider leveraging the efforts of Project 25 ISSI for use as the base set of standards for public safety related VoIP devices.

Completed a LabVIEW based software test suite to perform automated Radio Performance Measurements on Project 25 Land Mobile Radios. This software will support uniform and repeatable tests of Project 25 subscriber unit performance.

Demonstrated a functioning prototype of the DoC ISSI Emulation and Test System (DIETS), a SIP-based Project 25 Radiofrequency Subsystem (RFSS) emulator.

Developed technical approaches and contributions to Project 25 and Project MESA that advanced the definition of user requirements and critical interface standards.

Assisted COPS and SAFECOM management by developing the technical strategy for formally achieving telecommunications interoperability, deriving the process and procedures for involving local, state, and federal public safety practitioners in the strategy, and creating position papers and outreach documents that will help high-level Government officials better understand the methodology.

Played key roles in developing and shepherding through approval two critical standards in TIA TR-8: the ISSI (Inter-RF Subsystem Interface) - and the Fixed/Base Station Subsystem Interface (FSSI):

Project Efforts:

Standardization Efforts Related to Telecommunication and Information Technology Interoperability


The objective of this program is to support the SAFECOM and COPS Programs by providing engineering support through scientific analysis, standards leadership, and a technical liaison to practitioners to promote the identification, development and validation of standards for communication system products and services that support interoperable communications within the Justice/ Public Safety/Homeland Security community. Further, OLES provides technical assessments and evaluations of existing and emerging commercial products and services that may provide interim solutions under various interoperability scenarios.

Customer Needs

With the explosion of telecommunications and information technologies has come a disturbing trend – a lack of interoperability among systems. This problem is particularly acute in the justice/ public safety community where product lifecycles are especially long and manufacturer proprietary solutions abound. The problem is evidenced over and over as police and other agencies (fire departments, emergency medical services, etc.) fail to communicate with each other during multi-jurisdictional events (such as the Oklahoma City bombing or the September 11 terrorist incidents). Even in the absence of high-profile local, state, or regional calamities, daily interoperability problems continue to plague justice/public safety agencies nationwide.

The focus of the SAFECOM and COPS programs continues to be the development of robust, open telecommunications standards which promote interoperability amongst public safety-related communications devices and systems. In support of interoperable voice communications standards, OLES continued its focused involvement with Project 25 and the Telecommunications Industry Association (TIA) TR 8 standards committees—especially in the development of key interfaces that will fulfill the promise of seamlessly interconnecting different manufacturers' infrastructures. In 2005, at the request of the P25 Steering Committee, OLES expanded its role in TIA by heading the development of a compliance assessment program designed to ensure that users can procure mission-critical Project 25 equipment with a high level of confidence that the equipment complies with the relevant standards.

Technical Strategy

The current phase of the project can be seen as falling into the following five functional support areas:

Public Safety Statement of Requirements and Architechure Framework

OLES continues to work with SAFECOM to further develop the Public Safety Statement of Requirements (PS SoR) for Communications and Interoperability. This document which was initially released in 2004 is the recognized definition of long term communications requirements for the public safety community. The PS SoR provides a vision of public safety's communications and information sharing needs, defined by the practitioners themselves to meet their functional and operational requirements well into the future. The PS SoR is focused on the functional needs of public safety first responders — Emergency Medical Services (EMS) personnel, fire fighters, and law enforcement officers — to communicate and share information as authorized when it is needed, where it is needed, and in a mode or form that allows the practitioners to use it effectively. The communications mode may be voice, data, image, video, or multimedia that includes multiple forms of information. The original PS SoR release focused on qualitative requirements. Since then extensive research has been conducted using subjective practitioner evaluations to establish baseline quantitative requirements for both audio and video quality. The results of this latest research which provide more detail on technical parameters and values are planned to be released as a second of the PS SoR this fiscal year.

Based on the communications requirements outlined in the Public Safety Statement of Requirements, OLES and SAFECOM began development of the Public Safety Architecture Framework (PSAF). The architecture framework will provide public safety agencies with the necessary tools to compare and integrate legacy communication and information systems and allow them to leverage resources and migrate towards interoperability. The PSAF provides practitioners with a set of tools and a common lexicon for describing the elements of their local communications systems and enables practitioners to compare capabilities and equipment to achieve interoperability between jurisdictions. In addition to assisting the SAFECOM program in identifying needed standards by highlighting compatibility problems at key communications interfaces, the PSAF will also serve as a guide for localities planning for interoperability or technical capability upgrades. The PSAF enables engineers and planners to document their current public safety communication capabilities and analyze their system in relation to other systems. Ultimately, the PSAF will provide public safety with the ability to examine and develop both their operational and communications system capabilities.

With the publication of the PSAF in early 2006, OLES and SAFECOM are moving forward with a trial to demonstrate the utility of architecture framework principles within the public safety community by developing a database driven application which doesn't require enterprise architecture expertise. The first stage of the trial will leverage the Communications Assets Survey and Mapping (CASM) tool developed by DHS's Interoperable Communications Technical Assistance Program. The CASM tool's baseline capabilities, which gather operational data, will be extended to gather more technical details of a communications system. Public safety agencies participating in the trial activity will apply their real world experience to shape and define the tool and ensure it and the underlying architecture framework process are user friendly.

Project 25 Key Interfaces Standardization Acceleration

In early 2005 three Project 25 interfaces were identified as crucial for public safety agencies to purchase and implement both operable and interoperable P25-compliant systems. Those interfaces are listed below and represent where the most effective acceleration of the P25 Standards occurred in the past year and a half. While the initial releases will not fully satisfy all of the users' requirements, they will allow manufacturers to build interoperable equipment possessing the most common, basic features.

  • ISSI (Inter-RF Subsystem Interface) . This interface allows public safety agencies to interconnect systems on their wired networks (intranets). The initial ISSI protocol specification was approved by the TR8.19 group on May 31, 2006 as a TIA standard. This specification, also known as "Release 1," supports a limited feature set, i.e., trunked voice operation but no over-the-air rekeying (OTAR) for encryption, and limited roaming of mobile radio users between systems. This standard, TIA-102.BACA, was published by TIA in August, 2006. Compliance specification standards for the ISSI are under active development.
  • Fixed/Base Station Subsystem Interface (FSSI): This interface allows an RF site (with base station transmitters and receivers) to interconnect with an RF subsystem - the P25 system administrator and controller. The initial FSSI protocol specification was approved by the TR8.19 group on January 11, 2006 as a TIA standard. This standard, TIA-102.BAHA, was published by TIA in June, 2006. Compliance specification standards for the FSSI are under active development.
  • Console Subsystem Interface (CSSI): This interface allows public safety dispatchers and communication center supervisors to interconnect via their consoles with an RF subsystem. Completion of the FSSI, which enables direct basic console control of fixed/base station equipment, and the ISSI now serve as the supporting foundations for more comprehensive CSSI standards currently under development.

Project 25 Compliance AssessmetT Program

In April 2005, at the request of the Project 25 Steering Committee, OLES, again working on behalf of SAFECOM, began efforts to develop a conformity assessment program for Project 25 equipment, now known as the Project 25 Compliance Assessment Program. Since then OLES has worked with representatives from both user and industry communities to focus the efforts of the program and to develop an initial framework for the assessment program. To these ends the Project 25 Compliance Assessment Working Group (CAWG) was formed under the auspices of the Telecommunications Industry Association (TIA) to consider the processes and procedures necessary to implement a program. A key accomplishment of this group was a memorandum of understanding stipulating the basic assumptions for testing and the means by which test results would be collected and disseminated. That group has established a basic framework for the program and decided upon a fi rst-party testing regimen to back a Supplier's Declarations of Compliance.

At the recommendation of OLES, the Project 25 Compliance Assessment Process and Procedures Task Group was formed by expanding the scope of another committee to encompass all of compliance assessment. OLES representatives drafted and the committee accepted a work plan that prioritized the various conformance and interoperability test procedures—the test procedures that underpin the compliance assessment program. Subsequently, TIA has formed the TR-8.25 Compliance Assessment committee to address an increasing number of compliance assessment related issues.

The initial work of the Compliance Assessment Program focused on the Common Air Interface (CAI), the most mature of the P25 interfaces. Testing of the CAI begins with evaluations of interoperability for both trunked and conventional mode operation and are on track for completion by the end of calendar year 2006. Work is ongoing to update and publish more complete interoperability test procedures, and conformance test procedures for the CAI will follow.

Testing of wireline-based interfaces such as the ISSI poses additional challenges not the least of which is the need for new test equipment and metrology. In response to this challenge OLES representatives authored the ISSI Measurement Methods standards document and have undertaken the development of the DoC ISSI Emulation and Test System (DIETS) which provides a set of tools for testing emerging ISSI technologies. The tool will emulate a P25 Radiofrequency Subsystem (RFSS) and exercise the protocols defined in the ISSI standards. A complete test tool is being developed that will implement all of the ISSI conformance test cases being developed by TIA. In addition, the tool will include a packet capture and visualization tool that will support system analysis and troubleshooting. Future incremental enhancements to DIETS would enable the tool to support ISSI performance testing as well. The DIETS architecture is also capable of supporting conformance and performance testing for the Fixed Station and Console interfaces.

Public Safety Broadband Data Standards Efforts

OLES is driving the broadband standardization effort on behalf of public safety. OLES leadership in this area is evidenced by its sponsorship of the Chair for the APIC Broadband Task Group, and its support from the public safety community derives from its commitment to faithfully representing their requirements. The OLES strategy is to conduct extensive simulation work based on real world scenarios taken from the Public Safety Statement of Requirements. In support of this effort OLES sponsors the project leader for the simulation effort and coordinates the efforts of a contractor from Booze Allen Hamilton who performs the simulations in OPNET. The goal is for public safety to be able to quantify their specific spectrum needs and tie these needs directly back to a repeatable simulation effort. To date reports summarizing the findings of simulations of the first three discipline-specific scenarios from the Public Safety Statement of Requirements have been produced. These reports have been accepted by all participants in the APIC Broadband Task Group and have essentially become the working group's de facto findings. With OLES support the Task Group will soon be prepared to select an air interface for use in the 4.9 GHz band. This effort marks the first time that public safety will be standardizing broadband data communications, and as such, will have an enormous impact on the way first responders conduct day-to-day business.

OLES is also instrumental in the Project 34 User Needs Working Group. This is a working group made up of practitioners that determines the user needs and requirements for broadband communications. OLES has participated in writing many of the requirements documents produced by the P34 Working Group, including the latest Statement of Requirements for Incident Area Networking.

Owing to its contributions to public safety broadband data standards, OLES has been requested by both the SAFECOM Advisory Group and the National Public Safety Telecommunications Council to participate in a study of how public safety could better utilize the 700 MHz band for broadband data communications. While this work has just begun, it is expected that the deliverables will dramatically impact public safety's use of this spectrum. In support of this role, OLES sponsors the Co-Chair of NPSTC's newly formed Broadband Interoperability Working Group, which is charged with standardizing public safety's 700 MHz broadband spectrum.

OLES is also advancing the work of Project MESA on behalf of first responders in the United States. Project MESA is a global effort to address public safety communications needs and is a cooperative effort between TIA in the United States and ETSI in Europe. Project MESA aims to develop a worldwide set of specifications for public safety to create a global market for equipment and to promote interoperability at the international level. OLES's strategy in Project MESA has been to sponsor the Chair of the Technical Systems Group who then leverages the Public Safety Statement of Requirements to ensure that US public safety agency communications requirements are adequately represented and addressed.

Technology Evaluation and Engineering Support

OLES continues to evaluate commercial interim interoperability products for their ability to satisfy near term interoperability requirements. The various products are selected for evaluation by the SAFECOM Test and Evaluation Working group, which looks for those products which appear to have the greatest potential over the short and long-term as interim interoperability solutions.

OLES also responds to the immediate needs of the SAFECOM and COPS programs by performing other research and applied engineering activities as requested. These activities may include strategic and tactical planning, system engineering, technical analysis, economic benefit studies, etc. OLES also develops formal documents such as guides or handbooks, presentations, white papers, and other documentation to support existing program tasks and/or proposed initiatives. On occasion, at the request of NIJ, OLES provides technical representatives to evaluate proposals, designs, approaches, and other technical overtures submit-ted/offered to NIJ.


Revised Statements of Requirements (SORs) for both IT and wireless telecommunications applications, architectural framework documents, NIJ standards, reports, guides, guidelines, handbooks, white papers, and other products required to advance the CommTech Program and other interoperability-related efforts within NIJ.

Created October 22, 2008, Updated June 2, 2021