Combined channel estimator for pilot-assisted wireless OFDM communication systems

The paper investigates two types of combined channel estimator (CCE) for pilot-assisted orthogonal frequency division multiplexing mobile communication systems. The CCE-type1 is a double maximum-likelihood (ML) based estimator, which works under a limit condition that the number of pilot tones should not be smaller than the channel length. The bit-error-rate performance can be improved significantly by employing this estimator. The CCE-type2 is a second-order polynomial model and ML combined approach. It has better performance than the traditional approach when the limit condition is not satisfied. Simulation results are given to corroborate our discussion.