FM IBOC Coverage Prediction
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1. The document summarizes research by CRC on predicting coverage of FM-IBOC (in-band on-channel digital radio) systems using their CRC-COVLAB software. 2. Field measurement data from tests done by NPR and iBiquity on actual FM-IBOC broadcasts were used to validate the accuracy of the CRC-COVLAB FM-IBOC prediction module. 3. Results showed good correlation between predictions and measurements, with some minor discrepancies in one location, demonstrating the high accuracy of the CRC-COVLAB tool for FM-IBOC planning and interference analysis.
FM IBOC Coverage Prediction
- 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. FM-IBOC Coverage Prediction in CRC-COVLAB 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. One essential consideration in predicting FM-IBOC coverage is interference from adjacent analog FM stations. Interference from 1 st adjacent analog stations is most disruptive, especially when in the presence of both upper and lower 1 st adjacent stations. 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.
- 3. FM-IBOC Module Accuracy Does the module perform? Let’s take it for a test drive! Need field measurement data to compare with the simulation. Thanks to our friendly neighbors South of the border, we were to have access to FM-IBOC field measurements…
- 4. National Public Radio FM-IBOC Field Measurements 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 CRC was provided measurements from three cities: Chicago, Illinois: where the coverage is mostly noise limited (not very affected by interference) Oxford, Ohio: where the coverage is moderately affected by interference North Highlands, California: where the coverage is significantly affected by interference This offers a nice variety of interference situations to compare coverage predictions.
- 5. Simulations Parameters Propagation model: CRC-PREDICT 2.08 Terrain elevation database: Computamaps 250 m resolution Terrain type database: Computamaps 250 m resolution Transmitter parameters taken from FCC broadcast stations database. Receiver performance derived from CRC lab measurements. 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.
- 8. KQEI North Highlands, California
- 9. Observations on Measurements vs Simulation Results show a good correlation between NPR measurements and the performance/accuracy of the FM-IBOC module in CRC-COVLAB. Exception of the North-East sector of the WMUB Oxford, Ohio, simulation. There could be a discrepancy between the parameters recorded in the FCC database and the actual system, example the antenna radiation pattern. Simulation may be considering an interferer N-E that is not actually operating…needs further investigation.
- 10. From report: FM HD Radio TM System Performance At Elevated Carrier Levels , iBiquity Digital Corportion, December 2007 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. 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). Presented simulation vs measurement results for: Point Pleasant, New Jersey Detroit, Michigan FM-IBOC iBiquity Field Measurements
- 11. WRAT Point Pleasant, New Jersey
- 12. WRAT Point Pleasant, NJ : Digital Power 20 dB Below Analog Power
- 13. WRAT Point Pleasant, NJ : Digital Power 20 dB Below Analog Power
- 14. WRAT Point Pleasant, NJ : Digital Power 20 dB Below Analog Power
- 15. WRAT Point Pleasant, NJ : Digital Power 10 dB Below Analog Power
- 16. WRAT Point Pleasant, NJ : Digital Power 10 dB Below Analog Power
- 18. WCSX Detroit, Michigan : Digital Power 20 dB Below Analog Power
- 19. WCSX Detroit, Michigan : Digital Power 20 dB Below Analog Power
- 20. WCSX Detroit, Michigan : Digital Power 20 dB Below Analog Power
- 21. WCSX Detroit, Michigan : Digital Power 10 dB Below Analog Power
- 22. WCSX Detroit, Michigan : Digital Power 10 dB Below Analog Power
- 23. Conclusion 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. 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,… CRC will continue to provide expert advice to the Canadian Industry and Government. We often present these kinds of results to the Digital Radio Coordinating Group (DRCG).
- 24. Acknowledgements Barry McLarnon, BDMComm Martin-Pierre Lussier, CRC Patrick Pilon, CRC Measurements from: NPR Labs & iBiquity
- 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