A BEM-OTFS channel estimation method for high mobility 6G-V2X

Aiming at the problem that existing channel estimation methods are unable to track the channel parameter variations within a single frame under continuous Doppler spread channel (CoDSC) which leads to serious estimation errors, this paper proposes a basis expansion model (BEM) orthogonal time frequency space (OTFS) channel estimation method based on Cluster-Pruning Stagewise Weak Orthogonal Matching Pursuit (CP-SWOMP). This method first uses a discrete prolate spheroidal sequences (DPSS) as a basis function to model the channel response, converting the underdetermined channel estimation into a sparse reconstruction problem with basis coefficients. Then the basis coefficients are solved for using compressed sensing methods, the nearest neighbor clustering criterion is introduced into the Stagewise Weak Orthogonal Matching Pursuit (SWOMP) algorithm, and the atoms of the iterative intermediate process are subjected to a quadratic pruning operation, which solves the redundancy problem of the support set and improves the reconstruction accuracy. In this paper, multiple methods are simulated and validated at different normalized Doppler frequency, and the results demonstrate that the proposed method can achieve better normalized mean square error (NMSE) and bit error rate (BER) performance with less pilot overhead.