FM IBOC Coverage Prediction

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The Communications Research Centre Canada (CRC) has done extensive laboratory tests of the HD Radio system and as a result has developed an advanced FM-IBOC module in the CRC-COVLAB coverage prediction and interference analysis software. This presentation gives an overview of the HD Radio coverage studies comparing simulation with field measurements from NPR and IBiquity.

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FM IBOC Coverage Prediction

  1. 1. FM-IBOC Coverage Prediction Doris Camiré Radio Broadcast Systems & Transmission Communications Research Centre Canada Ottawa Western Association Broadcast Engineers (WABE) Annual Convention – Victoria, B.C., Dec 1, 2008
  2. 2. FM-IBOC Coverage Prediction in CRC-COVLAB <ul><li>As a result of CRC’s extensive laboratory tests on the performance of the FM-IBOC system, we were able to develop an advanced module to predict the coverage in CRC-COVLAB software. </li></ul><ul><li>One essential consideration in predicting FM-IBOC coverage is interference from adjacent analog FM stations. </li></ul><ul><li>Interference from 1 st adjacent analog stations is most disruptive, especially when in the presence of both upper and lower 1 st adjacent stations. </li></ul><ul><li>In CRC-COVLAB we consider interference from the 1 st , 2 nd and 3 rd adjacent stations, all having a compound effect on the FM-IBOC coverage. </li></ul>
  3. 3. FM-IBOC Module Accuracy <ul><li>Does the module perform? </li></ul><ul><li>Let’s take it for a test drive! </li></ul><ul><li>Need field measurement data to compare with the simulation. </li></ul><ul><li>Thanks to our friendly neighbors South of the border, we were to have access to FM-IBOC field measurements… </li></ul>
  4. 4. National Public Radio FM-IBOC Field Measurements <ul><li>NPR developed a field test unit which was shipped to dozens of public radio stations to gather field measurement data on the performance of FM-IBOC </li></ul><ul><li>CRC was provided measurements from three cities: </li></ul><ul><ul><li>Chicago, Illinois: where the coverage is mostly noise limited (not very affected by interference) </li></ul></ul><ul><ul><li>Oxford, Ohio: where the coverage is moderately affected by interference </li></ul></ul><ul><ul><li>North Highlands, California: where the coverage is significantly affected by interference </li></ul></ul><ul><li>This offers a nice variety of interference situations to compare coverage predictions. </li></ul>
  5. 5. Simulations Parameters <ul><li>Propagation model: CRC-PREDICT 2.08 </li></ul><ul><li>Terrain elevation database: Computamaps 250 m resolution </li></ul><ul><li>Terrain type database: Computamaps 250 m resolution </li></ul><ul><li>Transmitter parameters taken from FCC broadcast stations database. </li></ul><ul><li>Receiver performance derived from CRC lab measurements. </li></ul><ul><li>Note: In all simulations, the default parameters of CRC-COVLAB were used, there was no fine tuning or adjusting the simulation to fit the measurements. </li></ul>
  6. 6. WBEZ Chicago, Illinois
  7. 7. WMUB Oxford, Ohio
  8. 8. KQEI North Highlands, California
  9. 9. Observations on Measurements vs Simulation <ul><li>Results show a good correlation between NPR measurements and the performance/accuracy of the FM-IBOC module in CRC-COVLAB. </li></ul><ul><li>Exception of the North-East sector of the WMUB Oxford, Ohio, simulation. </li></ul><ul><ul><li>There could be a discrepancy between the parameters recorded in the FCC database and the actual system, example the antenna radiation pattern. </li></ul></ul><ul><ul><li>Simulation may be considering an interferer N-E that is not actually operating…needs further investigation. </li></ul></ul>
  10. 10. <ul><li>From report: FM HD Radio TM System Performance At Elevated Carrier Levels , iBiquity Digital Corportion, December 2007 </li></ul><ul><li>Field tests done by iBiquity on the FM HD Radio TM system to assess the system’s performance with an increase in the ratio of digital power to analog power. </li></ul><ul><li>Tests compare the performance at current power levels (digital power 20 dB below analog power) with elevated power levels (digital power 10 dB below analog). </li></ul><ul><li>Presented simulation vs measurement results for: </li></ul><ul><ul><li>Point Pleasant, New Jersey </li></ul></ul><ul><ul><li>Detroit, Michigan </li></ul></ul>FM-IBOC iBiquity Field Measurements
  11. 11. WRAT Point Pleasant, New Jersey
  12. 12. WRAT Point Pleasant, NJ : Digital Power 20 dB Below Analog Power
  13. 13. WRAT Point Pleasant, NJ : Digital Power 20 dB Below Analog Power
  14. 14. WRAT Point Pleasant, NJ : Digital Power 20 dB Below Analog Power
  15. 15. WRAT Point Pleasant, NJ : Digital Power 10 dB Below Analog Power
  16. 16. WRAT Point Pleasant, NJ : Digital Power 10 dB Below Analog Power
  17. 17. WCSX Detroit, Michigan
  18. 18. WCSX Detroit, Michigan : Digital Power 20 dB Below Analog Power
  19. 19. WCSX Detroit, Michigan : Digital Power 20 dB Below Analog Power
  20. 20. WCSX Detroit, Michigan : Digital Power 20 dB Below Analog Power
  21. 21. WCSX Detroit, Michigan : Digital Power 10 dB Below Analog Power
  22. 22. WCSX Detroit, Michigan : Digital Power 10 dB Below Analog Power
  23. 23. Conclusion <ul><li>We consider the FM-IBOC module of high accuracy and are confident in the use of CRC-COVLAB for FM-IBOC system planning and interference analysis. </li></ul><ul><li>CRC will continue to contribute with partners worldwide to the advancement of radio broadcast technologies and the evaluation of existing technologies: DAB+, DMB, IBOC, DRM,… </li></ul><ul><li>CRC will continue to provide expert advice to the Canadian Industry and Government. </li></ul><ul><li>We often present these kinds of results to the Digital Radio Coordinating Group (DRCG). </li></ul>
  24. 24. Acknowledgements <ul><li>Barry McLarnon, BDMComm </li></ul><ul><li>Martin-Pierre Lussier, CRC </li></ul><ul><li>Patrick Pilon, CRC </li></ul><ul><li>Measurements from: NPR Labs & iBiquity </li></ul>
  25. 25. For more information on Radio broadcast technologies research or coverage simulation software, come to visit us… www.crc.ca/crc-covlab Thank you! Doris Camiré Senior Research Engineer Radio Broadcast Systems Communications Research Centre doris.camire @crc.ca

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