Channel Estimation with Asynchronous Reception for User-Centric Cell-Free MIMO Systems

TL;DR

This paper introduces a novel channel estimation method for user-centric cell-free MIMO systems that effectively mitigates asynchronous reception issues, significantly improving accuracy and data rates.

Contribution

The paper proposes a new pilot design and matched filter approach to recover synchronization in asynchronous cell-free MIMO systems, enhancing channel estimation performance.

Findings

7.26 dB reduction in normalized mean square error

40% increase in data rate

Performance comparable to synchronous reception

Abstract

The user-centric, cell-free wireless network is a promising next-generation communication system, but signal synchronization issues arise due to distributed access points and lack of cellular structure. We propose a novel method to recover synchronous pilot reception by introducing new pilot sequences and a matched filter window, enabling orthogonality even with asynchronous reception. Our approach mimics synchronous transmission by extending training sequences. Analysis shows asynchronous reception's impact on channel estimation, and our method significantly improves performance with a small increase of training time overhead. Results demonstrate a 7.26 dB reduction in normalized mean square error and 40% increase in data rate, achieving performance levels comparable to the synchronous case.