Cyclostationarity-Based and Super-Imposed Pilot-Aided Maximum Doppler Spread Estimation for LOFDM Systems in Doubly-Dispersive Channels

摘要

The maximum Doppler spread, or equivalently, the mobile speed, is a measure of the spectral dispersion of mobile fading channel. Accurate estimation of the maximum Doppler spread is of importance in LOFDM systems which require the knowledge of the rate of channel variations to achieve its adaptive strategy. In this paper, aiming at the special characteristics of LOFDM signals, a cyclostationarity-based and superimposed pilot-aided maximum Doppler spread estimation algorithm for LOFDM systems over the doubly-dispersion channels is proposed, which avoids the waste of spectral efficiency in the traditional data-aided estimation algorithms and has a better performance and convergence speed compared with the blind estimation methods. Theory analyses and simulation results demonstrate that the proposed algorithm can obtain the effective estimation for a wide range of Doppler spreads under the condition that the power delay profile (PDP) of the channel is unknown and has a good mean square error (MSE) performance, while both the capability of anti-noise and the speed of convergence are nice. 【keyworks】LDFDM;Cycloststionarity;Doubly-Dispersive Channel;Superimposed Pilot;Maximum Doppler Spread;Estimation;