Superimposed-pilot-aided channel estimation for mobile OFDM

A superimposed-pilot-based channel estimation scheme for mobile orthogonal frequency division multiplexing systems is investigated. First, a least square estimator is developed to obtain some temporary channel estimates; meanwhile optimal pilot symbols are proposed with respect to the channel estimates´ mean square error. Final estimation is then computed by smoothing these temporary results. As shown in simulations, the proposed channel estimation approach achieves not only better performance but also higher spectrum efficiency than that of the conventional pilot-aided method.