Introduction to the Absolute Phase in Mobile Channels

The absolute phase is the accumulated phase change over an observation interval. It is a new variable for the mobile channel and can be simply derived from the wrapped phase or from the quadrature components. The absolute phase offers extra information about the channel, fostering new techniques for channel characterization and location estimation. However, the absolute phase has not been used in mobile communications. In this paper, the absolute phase is introduced including its mathematical definition and two different formulations. The mean of the absolute phase is derived for the mobile channel with directional scattering, including isotropic scattering as a special case. Simulations are used to support the analysis and discussion.