Study of Iterative Dynamic Channel Tracking for Multiple RIS-Assisted MIMO Systems

TL;DR

This paper proposes an iterative channel estimation scheme for multiple RIS-assisted MIMO systems that leverages LDPC codes and previous estimates to improve accuracy and reduce pilot overhead, enhancing 6G coverage.

Contribution

It introduces a novel iterative channel estimation method using LDPC-encoded pilots and previous estimates, specifically designed for multiple RIS-assisted MIMO systems.

Findings

Outperforms existing methods in simulation results.

Achieves significant reduction in pilot overhead.

Provides improved channel estimation accuracy under various conditions.

Abstract

The use of multiple Reconfigurable Intelligent Sur- faces (RIS) has gained attention in 6G networks to enhance coverage. However, the feasibility of deploying multiple RIS relies on efficient channel estimation and reduced pilot overhead. To address these challenges, this work proposes an iterative channel estimation scheme that exploits low-density parity-check (LDPC) codes, channel coherence time, and iterative processing to improve estimation accuracy while minimizing pilot length. Encoded pilots are used to strengthen the iterative processing, leveraging both pilot and parity bits, while previous estimates are incorporated to further reduce overhead. Simulations consider a sub-6 GHz scenario with non-sparse channels and multiple RIS under both LOS and NLOS conditions. The results show that the proposed method outperforms existing approaches, achieving significant gains with substantially lower pilot overhead.