A Geometric Scattering Model for Circularly Polarized Indoor Channels

Abstract

Wireless systems are being deployed in evermore complex environments, ones that can introduce multipath resulting in not only severe frequency selective fading but also signal depolarization. Polarization diversity is a known technique to mitigate such fades. To date, primarily linearly polarized (LP) systems have been used for indoor communications, but recently circularly polarized (CP) systems have received attention. As such there is motivation to better understand how both linearly and CP systems perform in depolarizing environments. In this article, we present a 3-D geometry-based stochastic channel model (GBSCM) for dual-polarized systems to evaluate circular and LP in cluttered settings. Using a Poisson distribution, the model generates a number of multipath scatterers. Measurements have been conducted at 2.4 GHz to validate the model. Leveraging parameters extracted from measured data, linear and circular polarization conditions are simulated for both line-of-sight (LOS) and non-LOS (NLOS) conditions. cross-polarization discrimination (XPD) and 1% link margins are considered as performance metrics. These metrics applied to both simulated and empirical data are both within 1 dB of each other.