System Implications of 14/11 GHz Path Depolarization. Part II: Reducing the impairments

Abstract

AbstractDual‐polarized co‐channel operation via international communications satellites places stringent requirements on the amount of interference that can be allowed from all sources. System design must allow for the depolarization caused by rain and ice crystals, the principal source of additional interference. In the 14/11 and 14/12 GHz bands, some paths are depolarization limited, particularly at lower path elevation angles, or become so with up‐link power control. Others are attenuation limited. Therefore, a means must be found to reduce the level of path depolarization to meet the requirements for path availability. In Part I or this paper, reference joint statistics of cross‐polarization discrimination/attenuation statistics were derived for a number of paths and climates to establish the additional fade and cross‐polarization discrimination margins required. This second paper addresses methods for reducing the system effects of path depolarization.Appropriate orientation of the polarization vectors at the spacecraft is shown to be an attractive alternative for spot‐beam applications. For all other situations, it is concluded that single‐parameter, phase‐only compensation at the earth terminal will meet all practical system requirements.