Improved Asymptotic Variance of the Associated Rician Phase Distribution

Whilst many common phase distributions have well-defined closed-form variance expressions, the well-known Rician phase (or Blachman-Bennett) distribution does not have any similar known expression. This Letter presents an asymptotic closed-form expression for the variance of the Rician phase distribution that is a significant improvement on existing expressions and straightforward to use. This new result takes advantage of the incomplete 3F1 hypergeometric function. We also introduce a normalized full-width half maximum (FWHM)