IAFC 150 anniversary logo

Project 25 Technology Interest Group Update

Project 25 and Multiple Vendors Sourcing

A key objective of Project 25 is a healthy competitive environment. There are today over 30 vendors providing equipment, software and services; 15 supply infrastructure equipment and 18 supply mobile and portable radios.

Project 25 systems are available in conventional and trunked applications. System architectures include single site, receiver voting, repeaters, wireline dispatch, multicast and simulcast. The original P25 goal to achieve multiple vendor sourcing is fulfilled. Learn more about who is providing what by visiting Products and Services page on the PTIG website.

Project 25 Means Interoperability

The TIA-102 standard suite is the foundation for interoperable two-way radio. The P25 interfaces and capabilities enable internal-agency interoperability, multiple-jurisdiction interoperability and multiple-vendor compatibility. Two of the P25 attributes that are key to fire-rescue budgets and operations are that P25 equipment is compliant with FCC regulations in multiple frequency bands and that P25 capabilities enable migration from legacy systems.

Project 25 Audio Performances and Testing

When concerns about digital radio performance in high-noise environments surfaced, the P25 industry listened. The Audio Performance Working Group (APWG), consisting of both users and manufacturers, was formed as one of the P25/TIA Standards process to characterize the background noise performance of analog and digital communication technology.

The Institute of Telecommunications Sciences (ITS) and the National Institute of Standards and Technology in Boulder, Colo., did the testing. That testing, involving nine scenarios, validated user concerns that high background noise could severely degrade both analog and digital communications.

ITS/NIST then conducted an additional 14 tests in 2010 and 2011, using P25 equipment with an improved vocoder. The testing included 25 kHz and 12.5 kHz analog channels in addition to P25. The testing also included two different brands of SCBA masks, plus scenarios having the radio channel degraded to simulate weak signal conditions, such as those encountered when deep into a building.

The final report on the follow-up testing is not complete, but a few items are notable. Preliminary conclusions indicate that the P25 system performed better with the new vocoder. In weak signal conditions, the P25 digital systems with the enhanced vocoder perform much better than analog. The new vocoder also processes PASS alarm sounds much better than previously. The ITS/NIST report will be released after the results have been thoroughly analyzed.

Project 25 Standards Are Under Continuous Improvement

Major efforts in recent years have included

  • the vocoder enhancements referred to for audio quality and noise environments
  • completion of audio test plans
  • expansion of the Common Air Interface to include TDMA technology to supplement the established FDMA technology 
  • wireline and inter-system interface additions that enable data security services and fleet management to be maintained or expanded across wide area systems

Project 25 TDMA

The P25 CAI is the common denominator that enables interoperability between and within many diverse arrays of radios and stations regardless of manufacturer. The FDMA CAI suite of standards was the first completed. The TDMA CAI core documents and testing procedures are now also completed.

The P25 TDMA CAI provides 6.25 kHz spectral efficiency. It’s important to be reminded that within P25, there is backward compatibility from FDMA to analog and from TDMA to FDMA. The backward compatibility of P25 ensures the ability to plan fire-rescue two-way radio systems with future migration to either FDMA or TDMA technology.

Project 25 ISSI

The P25 suite of standards enables interoperability with neighboring networks through the Inter-RF Subsystem Interface (ISSI). The interface allows users to roam from one network to another, allows for connectivity while maintaining autonomy and supports mixed-vendor backbones.

Project 25 Compliance Assessment Program

The P25 Standards include numerous test procedures for conformance, performance and interoperability. Recognizing a need to have independent testing and accreditation to recognize equipment compliance to the standards led to the creation of the Compliance Assessment Program (CAP) by NIST’s Office of Law Enforcement Standards, in partnership with DHS and in coordination with P25 users and manufacturers and TIA. Additional information on CAP can be found on the Responders Knowledge Base website and the SAFECOM website.

Bill Pagones is the executive director of the Project 25 Technology Interest Group.

Related News
You are not logged in.