Genuine P25 Interoperability: Tips and Traps When Moving to Digital Radio

1. Genuine P25 Interoperability: Tips and Traps When Movingto Digital Radio www.taitradio.com Scott Skibness Tait Communications

2. Learning Objectives An update on the latest standards, interfaces and certification bodies and their implications for procurement decisions Understand why the P25 Compliance Assessment Program matters to you With all of this why don’t all P25 radios work on all P25 networks?

3. Project 25: History Designed for public safety by public safety Developed in partnership between APCO and TIA • Initial P25 standards were released in 1995 • P25 is a suite of mobile radio standards and bulletins which define interoperable communications for emergency services • They are continuing to evolve; Phase 2 trunking is in progress The result? • True multi-source procurement and interoperability • Smooth migration from analog

4. Project 25/TIA 102 Standards Suite The standards suite allows for some features that are: • Mandatory • Standard options: where if offered they must follow the standard • Manufacturer’s extensions to the standard: these can fit within the framework of the standard Caveat: watch out for manufacturer extensions that are similar to standard options

5. Project 25: More Than An Air Interface

6. Project 25 Standards: Roll-out Phases Phase 1 • P25 requirements and standards for a digital Common Air Interface (CAI) using FDMA 12.5 kHz channels and for the supporting system • Must be backwards compatible with FM analog Phase 2 • P25 requirements and standards for a digital CAI using 6.25 kHz channels or equivalent and for the supporting system • Must be backwards compatible with Phase 1 digital onlyThe primary improvement in Phase 2 is spectral efficiency

7. Project 25 Standards Status: Phase 2 • Most vendors are offering P25 Phase 2 upgradable equipment today • A number of test documents are still to be started • Uses half rate vocoder in 2-slot TDMA • Conventional Phase 2: work will commence on conventional 2-slot TDMA What does this mean for you?

8. P25 Compliance Assessment Program (CAP) CAP Test Bulletins Lab Assessments Multi-Vendor CAP Testing Suppliers Declaration of Compliance Responder Knowledge Base Posting Supplier’s Declaration of Compliance (SDoC) Summary Test Reports (STR) SDoCs/STRs on the Responder Knowledge Base (RKB)

9. Responder Knowledge Base (RKB) Website www.rkb.us→ Other Content → Certifications and Declarations → P25 SDoCs

10. Why Do We Need The CAP? Choice for buyers • Multiple users on a single network can use the P25 technology and various vendors’ P25 products on that network • Users can purchase the right fit for their needs with more options Security to buyers • The CAP offers a formal assurance program • Confidence in interoperability P25 equipment meeting the CAP standards Federal grant money in the US is dependant on interoperable products … but the CAP is still of interest in other regions

11. Who Defines The CAP? Approved by the CAP Governing Board Comprised of representatives from US Government agencies Generally follows the TIA recommendations for compliance assessment tests References standard tests Published in Compliance Assessment Bulletins (CAB)

12. Four Vendors with P25 CAP Recognized Labs Worldwide • Standard test process to become recognized • Vendor hosted CAP interoperability testing in a recognized lab • Tait, Motorola, EF Johnson and Harris • Other CAP testing such as performance testing is also completed • After testing, SDoCs and STRs are published to the RKB website Goal: cooperation between P25 vendors for interoperability

13. Trade-offs Interoperability ≠ Total Interoperability • Proprietary extensions Performance ≠ Coverage Guarantees • Testing • Culpability

14. Why don’t all P25 radios work on all P25 networks? • Different interpretation of the standards • Different implementation of the standards • Usability of the radio • Requirement for non-standard functionality

15. Interpretation of the P25 standards • Different interpretations of the standard • Features outlined in the standard that WILL work • group calls • registration • affiliation • unit to unit calls • However… on most networks there are other features required. • Patch Calls • Dynamic Regrouping • Failsoft

16. Differences in Implementation Not all standards are clearly defined • Many of the items in the standards are open to interpretation • Control Channel Hunt – items like acquisition, retention, what is a valid CC, and when to leave are detailed but how to find one and select which to use or keep are not. • Or deployed with additional capabilities • Radio inhibit and uninhibit – The standard defines how this will work but the data is unencrypted as defined so vendors add encryptions within the system for these which limits the functionality to others.

17. Usability of the Radio Differences in features and operation. • ‘Usability’ is one of the major obstacles for having multiple vendors on a state-wide network. • Acceptance or certification testing is based on an existing terminal and how it operates and not the P25 standard • Scan configuration • Programming Units • Alert sounds and configuration

18. User Misunderstandings About the Standard Largely defined by the individual vendors, or the user when programming. Therefore NOT uniform. Vendor Proprietary Features Defined by the P25 Feature Sets At the 3 levels User Interface: Tones, Display, Lights, Knobs, etc. User Programming: Tones, Channels, Features, etc. Standard Options User Programming Interface: channel lists, pull down menus, Etc.. P25 Air Interface & Signaling: ID, Alarms, Features, etc. Core Features P25 Feature Sets User P25 Experience

19. Non-Standard Functionality Adding functionality that is not available to other suppliers • Network suppliers add services that help make its terminals function more efficiently. • Dynamic Power Control • Providing functionality that limit interoperability with other vendors radios on the network. • Non-standard Encryption – insist on AES or DES • OTAP • Limit what is granted in a license to a few features

20. Lesson Learned Examples from past systems • Non-standard frequency splits • Failsoft function with unique code words where in some cases it included a specific manufactures ID • Unused bits that change states from system to system. • Lack of testing on the system means some conditions are not found out until the units are deployed

21. Lessons Learned • Limit testing of “proprietary” features • Vendors need more than the minimum information to work effectively • Willingness of the network owners to work with the other vendors • Not all users will need or want the same functionality so make sure you are not limiting their choices with the certification process Test failures are not just a failure for a vendor They are a failure for the P25 standard and interoperability. SAVINGS– customers have seen a 30% to 40% savingsor more in the cost of subscriber units when multiple vendors radios are offered on a system.

22. Genuine P25 Interoperability: Tips and Traps When Movingto Digital Radio www.taitradio.com Scott Skibness Tait Communications