Performance analysis of LS and LMMSE channel estimation for 5G NR OFDM systems over time-varying fading channels

Abstract

Accurate and efficient acquisition of Channel State Information (CSI) is crucial for reliable data transmission using Orthogonal Frequency Division Multiplexing (OFDM) in 5G NR (New Radio) systems. Focusing on the 5G NR physical layer standards, this paper constructs a complete OFDM baseband transmission link and conducts an in-depth performance comparison and theoretical analysis of block pilot-based Least Squares (LS) and Linear Minimum Mean Square Error (LMMSE) channel estimation algorithms. A first-order autoregressive (AR1) model is employed to simulate slow and fast fading environments at different mobility speeds. A strictly discrete frequency-domain autocorrelation matrix is derived to address the errors of continuous integral approximation in traditional LMMS.