TETRA for Military Communications Dr Michael Street MIEE CEng Applied CIS Technology Branch CIS Division NATO Command,

1. TETRA for Military Communications Dr Michael Street MIEE CEng Applied CIS Technology Branch CIS Division NATO Command, Control & Consultation Agency

2. Introduction • NATO • NATO C3 Agency • Military use of civil P(A)MR technology • Trials – evaluation and assessment • Military contribution to civil technology and standards • Interoperability through standardisation

3. NATO’s Three Dimensions • First and Second dimensions of NATO • “The fundamental roles of NATO have always been concerned with security cooperation between member countries and, in more recent years, with Partner countries, in the political and defence fields. These have therefore been regarded as the first and second "dimensions" of the Alliance.” • Third dimension • Scientific and environmental co-operation • Responding to civilemergencies

4. What trails have the military done with TETRA ? BiH trial Propagation Does TETRA Security meet military requirements ? Effect of frequency allocation on military use of TETRA ? Interoperability Voice coders Military use of Civil P(A)MR

5. TETRA - Military Services; Civil Standard • Developed for Public Safety & Security with C3 features • TETRA services @Combat Net Radio features • has many large, security conscious user groups • Large user groups -- COTS equipment • Spectrum • Operates in Military UHF band • Spectrum efficient • Military UHF allocation is mainly 25kHz

6. NC3A TETRA Evaluation System • System procured in 1999 • Used for evaluation of TETRA services • Platform for testing of data applications • Interconnection and Interoperability experience • Early interoperability trials e.g. TETRA to Military tactical radio systems

7. TETRA on Exercises NC3A TETRA system used on exercises and trials • Combined Endeavour • Strong Resolve • Used to establish comms infrastructure for exercise • SFOR trial, Banja Luka • 2nd (National Communications) Signal Brigade, UK • JWID 2001

8. NC3A Trial Results • Easy to deploy • Setup time approx 15 mins • Easy to use • Users like it, minimal training time • Basic services meet users needs • Group calls, low rate data etc • DMO used during road move • Range governed by terrain • Limitation is laws of physics, not technology

9. Range and Propagation • Conducted propagation prediction in advance of trial • Measurements taken during trial correlated with prediction

10. Position Reporting • GPS equipped mobile terminals in vehicles • Position sent via TETRA SDS • NC3A developed “Black box” to covert position format for military applications

11. Military - Civil Interface • Interface between COTS TETRA network and military network • PC running Linux • NC3A developed interface software • Converts GPS to OTH/Gold format for MCIS

12. Deployable TETRA System Configuration AVLSGateway MCCIS MobilewithGPS AccessRouter MobileRadio COP, Web, E-mailApp Servers Base Station and Switch Handheld Voice Users ISDN Data Interface HiCom DigitalPABX COP, Web, E-Mail, Clients Portable Data Users Command & Control System SystemManagement

13. Secure Voice Communications • Security is an issue for commercial, public safety and military users • Military and public safety users require similar secure speech services • Provide security against disruption - eavesdropping, spoofing and denial of service • Air interface and end-to-end encryption • Authentication • Key management • Users still want interoperability - securely

14. TETRA Security and Fraud Prevention Group Guidance on implementing interoperable end-to-end encryption within ETSI Standards Prepared with public safety, commercial & military input • SFPG Rec 02 gives guidance within the standards • Choice of algorithms up to users • Support for TETRA Release 2 (additional vocoders) • SFPG Security Masterclass Courtesy of D Parkinson, BT Exact

15. TETRA Standards SFPG Recommendation 02 End to End Encryption Algorithm Vocoder ETSI Standards and SFPG Recommendations • ETSI standards give flexibility on how to implement End to end encryption • SFPG Rec 02 gives guidance within the standards • Choice of algorithms up to users • Support for TETRA Release 2 (additional vocoders) Commercial or national (public safety or military) algorithm Vocoder (TETRA ACELP, AMR or MELPe)

16. End to End Security • End-to-end Secure TETRA terminals on trial by NC3A / SFOR / BRITFOR • SFPG Rec 02 v3 • Support for AES • Advanced Encryption Standard • NSA competition, 128 bit • SFPG Rec 02 can support additional voice codecs • Approval for military use • Needs approval by the same bodies who approve Public Safety security Courtesy of THALES

17. NATO Voice Coder TETRA release 2 requested additional voice codecs - 3G AMR plus …. “new voice coders utilising the latest low bit-rate technology”

18. NATO Voice Coder Stanag 4591 • Pros • Low data rate - 2400 bps • Performance comparable to TETRA 1 • Suppression of background noise • Developed for high noise environments • Interoperable with other systems • Many military and some government systems use voice coder • IPR free • Cons • Frame length is 22.5 ms, • Not a convenient size for TETRA • IPR • Other information • 1200 bps mode – not relevant to TETRA • Benefits too small • Costs too great

19. HMMWV Bradley Fighting Vehicle LeClerc Tank Blackhawk helicopter Mirage 2000 F-15 The New NATO Voice Coder:Tested in a wide range of environments Quiet Modern Office Gaussian noise MCE field shelter Automobile .. and in English, French, German, Dutch, Polish and Turkish

20. Selecting the new NATO Voice Coder 3 test labs x 9 coders (+ 8 MNRU levels) x £5 tests • Over 28,000 files • Over 13 GB of processed speech data • Over 200 hours of speech x £ 12 noise conditions x £88 files per test

21. Military vs Civil Vocoders Intelligibility (%) Female speaker Military voice coder (STANAG 4591) offers comparable or improved performance over voice coders used in existing COTS PMR systems. Throughput requirements are much reduced. Designed to work in noisy environments.

22. Further information on STANAG 4591 Stanag 4591 test and selection process Street MD and Collura JS, “The test and selection of the future NATO narrow band voice coder”, RCMCIS - NATO Regional Conference on Military CIS, Warsaw, Zegrze, October 2001. Street MD, “Selection of the future NATO narrow band voice coder”, NC3A Technical Notes 881 & 912. http://nc3a.info/Voice MELPe: the selected voice coder Collura JS and Rahikka DJ, “Interoperable secure voice communications in tactical systems, IEE coll. on Speech coding algorithms for radio channels, London, February 2000. An overview of the MELP voice coder and its use in military environments http://www.iee.org/OnComms/pn/communications Collura JS, Rahikka DJ, Fuja TE, Sridhara D and Fazel T, “Error coding strategies for MELP vocoder in wireless and ATM environments”, IEE coll. on Speech coding algorithms for radio channels, London, February 2000. Performance of MELP with a variety of different error correction mechanisms http://www.iee.org/OnComms/pn/communications NC3A’s STANAG 4591 Server http://s4591.nc3a.nato.int

23. Frequency Allocation in Europe 380 383 385 390 393 395 400 Public Safety & Security Currently Reserved NATO Military • MoU on common frequency allocation has been signed by most European countries • Some nations sharing allocation and responsibility for public safety and commercial use - operational benefits • Could share military and civil allocations - operational benefits, political risks

24. Does TETRA meet military requirements ? • Services þ • Applications þ • Ease of deployment þ • Interoperability þ • Security ¨