Semi-Data-Aided Channel Estimation for MIMO Systems via Reinforcement Learning

TL;DR

This paper introduces a semi-data-aided MIMO channel estimation method using reinforcement learning to select reliable symbols, reducing latency and improving estimation accuracy compared to traditional approaches.

Contribution

It proposes a novel RL-based strategy for semi-data-aided channel estimation in MIMO systems, enabling earlier updates and better performance.

Findings

Reduces channel estimation latency significantly.

Mitigates estimation errors caused by limited pilot signals.

Enhances detection performance in MIMO systems.

Abstract

Data-aided channel estimation is a promising solution to improve channel estimation accuracy by exploiting data symbols as pilot signals for updating an initial channel estimate. In this paper, we propose a semi-data-aided channel estimator for multiple-input multiple-output communication systems. Our strategy is to leverage reinforcement learning (RL) for selecting reliable detected symbols among the symbols in the first part of transmitted data block. This strategy facilitates an update of the channel estimate before the end of data block transmission and therefore achieves a significant reduction in communication latency compared to conventional data-aided channel estimation approaches. Towards this end, we first define a Markov decision process (MDP) which sequentially decides whether to use each detected symbol as an additional pilot signal. We then develop an RL algorithm to efficiently find the best policy of the MDP based on a Monte Carlo tree search approach. In this algorithm, we exploit the a-posteriori probability for approximating both the optimal future actions and the corresponding state transitions of the MDP and derive a closed-form expression for the best policy. Simulation results demonstrate that the proposed channel estimator effectively mitigates both channel estimation error and detection performance loss caused by insufficient pilot signals.