Semi-blind Channel Estimation for Massive MIMO LEO Satellite Communications

TL;DR

This paper introduces decision-directed semi-blind channel estimators for massive MIMO LEO satellite systems, addressing channel aging and outperforming pilot-based methods in dynamic environments.

Contribution

It proposes two semi-blind estimators, including a modified version that mitigates channel aging, enhancing estimation accuracy in highly dynamic satellite channels.

Findings

Modified estimator outperforms pilot-based in mean square error

Achieves symbol error rate comparable to perfect channel knowledge

Effectively mitigates channel-aging effects

Abstract

This letter proposes decision-directed semi-blind channel estimation for massive multiple-input multiple-output low-Earth-orbit satellite communications. Two semi-blind estimators are proposed. The first utilizes detected data symbols in addition to pilot symbols. The second, a modified semi-blind estimator, is specially designed to mitigate the channel-aging effect caused by the highly dynamic nature of low-Earth-orbit satellite communication channels -- an issue that adversely impacts the performance of pilot-based estimators. Consequently, this modified estimator outperforms an optimal pilot-based estimator in terms of normalized mean square error and achieves symbol error rate performance comparable to that of a Genie-aided (perfectly known channel) detector. The trade-offs between the proposed estimators are also examined.