Gridless Iterative Near-Field Terahertz Channel Estimation for Dual Wideband UM-MIMO Systems

This paper presents the Gridless Iterative Near-field Terahertz Channel Estimation (GLINT-CE) technique, tailored for Full-dimensional Ultra-massive Spatial non-stationary Extensible Dual-wideband multiple-input-multiple-output (FUSED-MIMO) systems, addressing dual wideband effects and spatial non-stationarity (SNS) for scalable 6G communications. Utilizing uniform planar arrays at both the base station and user equipment to support the system’s full-dimensional architecture, the channel is described as a function of frequency-dependent gains, dual-wideband near-field steering vectors, and SNS. By formulating the CE as a convex optimization problem leveraging joint subcarrier atomic norm minimization, the GLINT-CE achieves superior estimation accuracy, as validated by simulation results outperforming existing methods.