ANALYTICAL EVALUATION OF THE EFFECT OF CROSSPOLARIZATION IN A POLARIZATION DIVERSITY MIMO SATELLITE TO GROUND LINK

Abstract

Any communication link that uses an artificial satellite in its propagation path is referred to as satellite communication. In today's world, satellite communications are critical. Over 2000 artificial satellites are currently in use. They are utilized for traditional pointto-point communications, mobile applications, and the distribution of TV and radio programming and can be found in geostationary, Molniya, elliptical, and low Earth orbits. The polarization orthogonal to the desired polarity is known as cross polarization. For example, if an antenna's fields are intended to be horizontally polarized, the crosspolarization in this case is vertical. As a result, most antenna radiation patterns are provided. Polarization diversity is one of the most important techniques to increase the capacity of a Multiple Input Multiple Output (MIMO) antenna system from satellite to ground link. However, such link is highly degraded to cross-polarization effect. MIMO technique may provide better performance of such system. So attempt is made to evaluate the cross-polarization induced crosstalk in a MIMO satellite link using polarization diversity. Analysis is developed to find the interference due to cross-polarization in a 2×2 MIMO and 4×4 MIMO satellite link. The expression of signal to interference plus noise ratio (SINR) is developed. The Bit-Error-Rates (BER) performance results are evaluated for different environments like Open area, Sub-urban area, Urban area and Aeronautical/Marin area. The power penalty for LOS component of 4×4 MIMO satellite to ground communication system. 0.1dB, 1.5 dB, 2.5dB and 4.0 dB power penalty are measured for open, sub-urban, urban and aeronautical/marine area which are slightly higher than 2×2 MIMO system. So, 4×4 MIMO system gives better output with low power penalty. The power penalty is compared for three different channel components like LOS components (β), Reflection components (ξ) and Diffused components (α). The LOS component gives the higher power penalty which 0.5 dB to 0.9 dB than other diffused component is 0.1 dB to 0.5 dB and reflection component is less than 0.1dB to 0.3dB. It is found the satellite to ground link suffers power penalty due to crosspolarization which is significant for A/M area and least penalty for Open area environment.