Performance analysis of LS and LMMSE channel estimation for 5G NR OFDM system

Abstract

Accurate CSI acquisition is critical for reliable OFDM transmission in 5G NR. This paper establishes an OFDM baseband link and compares LS and LMMSE channel estimation. An AR1 model simulates slow and fast fading. To reduce approximation error in traditional LMMSE, a discrete frequency-domain autocorrelation matrix is derived. Simulations show LMMSE outperforms LS in slow fading. In fast fading, time-domain linear interpolation suppresses the error floor and tracks time-varying channels.