基于波束分裂效应的XL-MIMO近场宽带信道估计研究OA

Aiming at the channel estimation accuracy degradation caused by the Beam Split(BP)effect in Extremely Large-scale Multiple-Input Multiple-Output(XL-MIMO)near-field wideband systems for 6G wireless communication networks,a Bilinear Pattern Detection(BPD)algorithm is proposed based on subcarrier grouping and gridless optimization with the simplex method.Due to the BP effect in near-field wideband systems,the subcarriers of the wideband system are grouped,and the bilinear patterns of angle and distance for each subcarrier group are calculated.By jointly utilizing the bilinear pattern information of all subcarrier groups,the maximum response position of cross-subcarrier frequency-correlated energy is captured,and the Polar-domain Simultaneous Orthogonal Matching Pursuit(P-SOMP)algorithm is adopted to conduct preliminary estimation of the angle and distance parameters of channel paths under discrete grids.Considering that the angle and distance parameters of channel paths in actual wireless propagation have the characteristic of continuous values,discrete grid modeling inevitably introduces grid mismatch errors.Therefore,the simplex method is employed to perform gridless refined optimization on the preliminarily estimated path information.Simulation results show that the proposed algorithm can reduce the impact of the BP effect,and improve significantly the channel estimation performance in near-field wideband systems compared with the conventional BPD algorithm.