WMO Radio Spectrum Workshop-Meteorological Radar Spectrum Issues

1. WMO Radio Spectrum Workshop-Meteorological Radar Spectrum Issues Presented By: David Franc Office of Radio Frequency Management March 2006

2. Purpose • Provide background information on, and current status of radio frequency issues that may impact global meteorological radar operations, and identify items for consideration by Members • This section of the workshop covers radars used for monitoring the atmosphere with the exception of Wind Profiler Radars

3. Outline • Meteorological radar bands • ITU-R Recommendations • Spectrum issues • WRC-2007 Agenda Item 1.3 • WRC-2007 Agenda Item 1.4 • JRG-1A/1C/8B • Work of Working Party 8B (WP 8B) • Important points

4. Meteorological Radar Bands

5. Meteorological Radar Bands • Three allocations exist in the Radio Regulations specifically identified for meteorological radars • 2700-2900 MHz- ground based radars • 5600-5650 MHz- ground based radars • 9300-9500 MHz- ground based and airborne radars • Depending on type of use, radionavigation and radiolocation bands can also be used

6. Need for 3 Frequency Bands? • System cost, complexity and operating range are all limitations that can be addressed through additional engineering and funding • Severe weather performance is a physical limitation that can not be addressed through additional engineering or funding • Severe weather performance is dependent upon frequency of operation

7. Severe Weather Performance Limitation • The ability of a meteorological radar to measure high wind speeds at its outer operational range is limited by the frequency of operation v * r  1/f Therefore, as frequency increases, the maximum range or maximum observable velocity, or both must decrease Maximum range Frequency Maximum velocity

8. Performance Comparison of Bands System Cost: Highest- 2700-2900 MHz Lowest- 9300-9500 MHz System Complexity: Highest- 2700-2900 MHz Lowest- 9300-9500 MHz Operating Range: ~450 km- 2700-2900 MHz ~200 km- 5600-5650 MHz <75 km- 9300-9500 MHz Severe Weather Highest- 2700-2900 MHz Performance: Lowest- 9300-9500 MHz

9. ITU-R Meteorological Radar Recommendations

10. Technical and Operational Characteristics • The following Recommendations provide technical and operational characteristics of meteorological radars • ITU-R M.1464: 2700-2900 MHz • ITU-R M.1460: 2900-3100 MHz • ITU-R M.1638: 5250-5850 MHz • ITU-R M.[8B.8-10GHZ]: 8-10 GHz* • Use: Information for conducting sharing studies *- Still under development within WP 8B

11. ITU-R M.1461 • Content: General procedures for conducting sharing studies with radars • Use: Guidance to conduct sharing studies • M.1461 is very generic and does not address the specificneeds of meteorological radars • Companion recommendation on meteorological radars under development within WP 8B

12. Wind Profiler Technical and Operational Characteristics • The following provide technical and operational characteristics of Wind Profiler Radars • ITU-R M.1226: Around 50 MHz • ITU-R M.1085: Around 400 MHz • ITU-R M.1227: Around 1000 MHz • Use: Information for conducting sharing studies • In need of review and update

13. Current Spectrum Issues

14. Current Spectrum Issues • WRC Agenda Item 1.3 • WRC Agenda Item 1.4 • JRG-1A/1C/8B: Radar emission masks • Working Party 8B • Compatibility analysis procedures • Protection criteria • Statistics-based compatibility analysis

15. WRC-Agenda Item 1.3 • Objective: • Upgrade radiolocation service (radars) to primary status in 9300- 9500 MHz • Earth exploration satellite service (EESS) allocation extension into 9300-9500 MHz • Impact: • Radiolocation upgrade raises the status of meteorological radars to primary status • Extension of EESS in 9300-9500 MHz could impact meteorological radars

16. Agenda Item 1.3 (continued) • Status: • Studies underway to evaluate impact of EESS to meteorological radars in 9300-9500 MHz • EESS extension could be placed in 9800-10000 MHz- not preferred approach • Advantages: • EESS could have meteorological applications • Radiolocation upgrade important for meteorological radar operations

17. Agenda Item 1.4 • Objective: • Consider frequency related issues associated with IMT-2000 and IMT Advanced • IMT-2000: Third generation (3G) mobile telecommunications • IMT Advanced: Fourth generation mobile telecommunications • Impact: • 2700-2900 MHz has been identified as a candidate band for Agenda Item 1.4 • Use of band for IMT-2000 or IMT Advanced will cause loss of spectrum for meteorological operations

18. Agenda Item 1.4 (continued) • Status: • WRC-2000: studies on impact to existing users (radars) were incomplete- created preliminary WRC-2007 Agenda Item • WRC-2003: studies showed IMT-2000 and existing systems were incompatible - Agenda Item deleted from WRC-2007 agenda • Studies now being updated for re-submission to ITU-R • Advantages: • None to meteorological operations

19. JRG-1A/1C/8B • Objective: • Develop ITU-R Recommendation(s) on radar emission masks • Emission masks define the required roll-off from the fundamental frequency • Impact: • Could place design limitations on radar technology • Advantages: • Limit adjacent channel and adjacent band interference • Increased spectrum efficiency

20. JRG-1A/1C/8BEmission Mask Example #1 Source: JRG-1A/1C/8B Doc. 52

21. JRG-1A/1C/8BEmission Mask Example #2 Source: JRG-1A/1C/8B Doc. 52

22. JRG-1A/1C/8B Work Plan • Define necessary 20 dB and 40 dB bandwidth for various radar technologies • Define roll-off beyond 40 dB bandwidth- 20 dB or 40 dB per decade • Need emission data and characteristics for example radars • Ensure realistic limits are established • Identify technology that needs different limits

23. Work of Working Party 8B (WP 8B) • Compatibility analysis procedures • Statistics-based compatibility analysis • Protection criteria

24. Compatibility Analysis Procedures • Methods used for evaluating impact of sharing spectrum between radars and other services • Meteorological radars are different than other radars • WP 8B developing a document specific to Meteorological Radars

25. Statistics-Based Compatibility Analysis • WP 8B is studying ways to use statistical analysis to improve the accuracy of sharing studies • May allow for use of more accurate propagation models • Could require radar operators to accept interference for short periods of time • Exceedance value greater than 0% associated with Protection Criteria

26. Radar Protection Criteria • Protection Criteria- the maximum interference level threshold for protection of radar • Protection criteria for meteorological radars dependent on • Base product accuracy • Minimum usable signal-to-noise ratio • Radar receiver noise level • Current meteorological radar protection criteria not clearly defined in the ITU

27. Important Points

28. Important Points • WRC-2007 Agenda Item 1.3 • Radiolocation upgrade benefits meteorological radar operations • EESS extension into 9300 - 9500 MHz • May impact meteorological radars • may also benefit meteorological operations • WRC-2007 Agenda Item 1.4 • The band 2700-2900 MHz inappropriate for use by IMT-2000 and IMT Advanced

29. Important Points (continued) • JRG-1A/1C/8B • Should be followed to ensure emission masks do not overly restrict radar design • Other Work of WP 8B • Follow discussions on compatibility analysis procedures, including use of statistics to ensure meteorological radars will be protected

30. Important Points (continued) • Work with your National Spectrum Regulators • Raise their awareness of spectrum needs for meteorological radar operations • Participate in the meetings of the ITU if resources allow • Ensure your radar system characteristics and requirements are documented in ITU-R recommendations