Skip to main content

Research Repository

Advanced Search

Diversity improvement estimation from rain radar databases using maximum likelihood estimation

Paulson, Kevin S.; Watson, Robert J.; Usman, Isa S.


Kevin S. Paulson

Robert J. Watson

Isa S. Usman


This research examines route diversity as a fade mitigation technique in the presence of rain, for terrestrial microwave links. The improvement in availability due to diversity depends upon the complex spatio-temporal properties of rainfall. To produce a general model to predict the advantage due to route diversity it is necessary to be able to predict the correlation of rain attenuation on arbitrary pairs of microwave links. This is achieved by examination of a database of radar derived rain rate fields. Given a representative sample of rain field images, the joint rain attenuation statistics of arbitrary configurations of terrestrial links can be estimated. Existing rain field databases often yield very small numbers of high joint attenuation events. Consequently, estimates of the probability of joint high attenuation events derived from ratios of the number of occurrences can be highly inaccurate. This paper assumes that pairs of terrestrial microwave links have joint rain attenuation distributions that are bi-lognormally distributed. Four of the five distribution parameters can be estimated from ITU-R models. A maximum likelihood estimation (MLE) method is used to estimate the fifth parameter, i.e., the covariance or correlation. The predicted diversity statistics vary smoothly and yield plausible extrapolations into low probability situations. © 2006 IEEE.


Paulson, K. S., Watson, R. J., & Usman, I. S. (2006). Diversity improvement estimation from rain radar databases using maximum likelihood estimation. IEEE Transactions on Antennas and Propagation, 54(1), 168-174.

Journal Article Type Article
Acceptance Date Jan 31, 2006
Publication Date Dec 1, 2006
Print ISSN 0018-926X
Publisher Institute of Electrical and Electronics Engineers
Peer Reviewed Peer Reviewed
Volume 54
Issue 1
Pages 168-174
Keywords Electrical and Electronic Engineering
Public URL