Doppler Spread Estimation by Subspace Tracking for OFDM Systems
  This paper proposes a novel maximum Doppler spread estimation algorithm for OFDM systems with the comb-type pilot pattern. By tracking the drifting delay subspace of the multipath channel, the time correlation function is measured at a high accuracy, which accordingly improves the estimation accuracy of the maximum Doppler spread considerably. 
Xiaochuan Zhao (1), Tao Peng (1), Ming Yang (1) and Wenbo Wang (1)   ((1) Beijing University of Posts and Telecommunications...