Variance state propagation for uplink channel estimation in LEO satellite systems

Abstract This paper, considers the channel estimation problem of uplink low Earth orbit (LEO) satellite orthogonal frequency division multiplexing (OFDM) system. By exploiting structured sparsity in delay‐Doppler‐angle domain, is formulated as a block‐sparse signal recovery problem. The variance state propagation (VSP) framework extended to solve such Considering that delay, Doppler shift, and angle departure (AoD) each path may not exactly fall on presumed discrete grid points, an expectation maximization (EM) based parameter learning scheme VSP iteratively update parameters introduced. Simulation results demonstrate proposed approach achieves substantial performance gain over existing methods.