Low-complexity Kalman channel estimator structures for OFDM systems with and without virtual carriers

Kalman channel estimators are optimal (MMSE) linear estimator. However, the direct implementation of the Kalman equations is too complex to be applied to practical OFDM systems with many subcarriers. In this paper, low-complexity structures for Kalman channel estimators are proposed for OFDM systems with and without virtual carriers that use a circular constellation. Simulation results show that the proposed low-complexity Kalman channel estimators almost achieve the performance of the perfect channel estimator.