Recent Evolution of Itu Method for Prediction of Multipath Fading on Terrestrial Microwave Links
Progress In Electromagnetics Research Symposium Proceedings, Marrakesh, Morocco, Mar. 20–23, 2011 1375
Recent Evolution of ITU Method for Prediction of Multipath Fading on Terrestrial Microwave Links
Basile L. Agba1 , Olfa Ben-Sik-Ali1 , Robert Morin2 , and Germain Bergeron2
1
Institut de Recherche d’Hydro-Qu´bec, 1800 Lionel-Boulet, Varennes, Qu´bec, Canada e e 2 Hydro-Qu´bec, 15000 University, Montreal, Qu´bec, Canada e e
Abstract— Three methods are commonly used to predict multipath fading on terrestrial lineof-sight (LOS) links namely Barnett-Vigants and Morita methods used respectively in North America and Japan, and the worldwide ITU method. This later gains in importance even in North America and in Japan, due to the regular updates proposed by Study Group 3 of the ITU Radiocommunications sector. The ITU recommendation, ITU-R P.530 provides guidelines based on fading measurements of 251 links in various geoclimatic regions. Since 1978, thirteen revisions were proposed. The paper reviews the evolution of ITU-R P.530 from 1997 to 2009 with focus on the difference between the last two revisions (Rev. 12 versus Rev. 13). These differences concern mainly the geoclimatic factor, which depends on the refractivity gradient and the terrain roughness, and the multipath fade occurrence factor that affects worst month outage probability. The paper also presents parametric studies carried out using our prediction tool, Microwave link simulator, to determine the critical parameters affecting link performance. In our studies, 20 links located in Quebec, Canada, are designed based on real-world parameters. The detailed link profiles are known and refractivity gradients are extracted from ITU database according to ITU-R P.453-9. Climatic conditions are also taken into account using local rain database. The results of this work show that three climatic parameters, namely rain intensity, refractivity gradient and annual mean temperature are critical. Likewise for
Recent Evolution of ITU Method for Prediction of Multipath Fading on Terrestrial Microwave Links
Basile L. Agba1 , Olfa Ben-Sik-Ali1 , Robert Morin2 , and Germain Bergeron2
1
Institut de Recherche d’Hydro-Qu´bec, 1800 Lionel-Boulet, Varennes, Qu´bec, Canada e e 2 Hydro-Qu´bec, 15000 University, Montreal, Qu´bec, Canada e e
Abstract— Three methods are commonly used to predict multipath fading on terrestrial lineof-sight (LOS) links namely Barnett-Vigants and Morita methods used respectively in North America and Japan, and the worldwide ITU method. This later gains in importance even in North America and in Japan, due to the regular updates proposed by Study Group 3 of the ITU Radiocommunications sector. The ITU recommendation, ITU-R P.530 provides guidelines based on fading measurements of 251 links in various geoclimatic regions. Since 1978, thirteen revisions were proposed. The paper reviews the evolution of ITU-R P.530 from 1997 to 2009 with focus on the difference between the last two revisions (Rev. 12 versus Rev. 13). These differences concern mainly the geoclimatic factor, which depends on the refractivity gradient and the terrain roughness, and the multipath fade occurrence factor that affects worst month outage probability. The paper also presents parametric studies carried out using our prediction tool, Microwave link simulator, to determine the critical parameters affecting link performance. In our studies, 20 links located in Quebec, Canada, are designed based on real-world parameters. The detailed link profiles are known and refractivity gradients are extracted from ITU database according to ITU-R P.453-9. Climatic conditions are also taken into account using local rain database. The results of this work show that three climatic parameters, namely rain intensity, refractivity gradient and annual mean temperature are critical. Likewise for
References: 1. Barnett, W. T., “Multipath propagation at 4, 6 and 11 GHz,” Bell System Technical Journal, Vol. 51, No. 2, 311–361, February 1972. 2. Morita, K., “Prediction of rayleigh fading occurrence probability of line of sight microwave links,” Rev. Elec. Comm. Lab. (Japan), Vol. 18, 310–321, November 1970. 3. International Telecommunication Union (ITU-R), “Propagation data and prediction methods required for the design of terrestrial line-of-sight systems,” Recommendation UIT-R P.530-12, 2005. 4. International Telecommunication Union (ITU-R), “Propagation data and prediction methods required for the design of terrestrial line-of-sight systems,” Recommendation UIT-R P.530-13, 2009. 5. Olsen, R. L. and T. Tjelta, “Worldwide techniques for predicting the multipath fading distribution on terrestrial L.O.S links: Comparison with regional techniques,” IEEE Transactions on Antenna and Propagation, Vol. 51, No. 1, 23–30, January 2003.