Robust Precoding via Characteristic Functions for VSAT to Multi-Satellite Uplink Transmission

TL;DR

This paper introduces a robust precoding method for VSAT uplink transmissions to multiple satellites, leveraging characteristic functions to handle positional uncertainties and optimize signal quality.

Contribution

It proposes a low-complexity precoder design that accounts for satellite position uncertainty using characteristic functions, enhancing uplink performance under imperfect information.

Findings

Achieves capacity with perfect satellite position knowledge.

Performance remains robust with moderate positional uncertainties.

Effective for large inter-satellite distances.

Abstract

The uplink from a very small aperture terminal (VSAT) towards multiple satellites is considered, in this paper. VSATs can be equipped with multiple antennas, allowing parallel transmission to multiple satellites. A low-complexity precoder based on imperfect positional information of the satellites is presented. The probability distribution of the position uncertainty and the statistics of the channel elements are related by the characteristic function of the position uncertainty. This knowledge is included in the precoder design to maximize the mean signal-to-leakage-and-noise ratio (SLNR) at the satellites. Furthermore, the performance w.r.t. the inter-satellite distance is numerically evaluated. It is shown that the proposed approach achieves the capacity for perfect position knowledge and sufficiently large inter-satellite distances. In case of imperfect position knowledge, the performance degradation of the robust precoder is relatively small.