Pilot-Power Allocation Scheme for Channel Estimation in OFDM Systems with Quasi-Static Channels

In orthogonal frequency division multiplexing (OFDM) systems, the equally-powered pilots (EPP) scheme is known to provide the best channel estimation performance when the channel status is unknown. In this study, it is shown that if we assume the channel correlation function (CCF) of a quasistatic channel is perfectly known at the receiver, all of the available pilot power should be allocated to the pilot sub-carrier with the maximum channel amplitude. In addition, a practical water-filling-type power allocation scheme, designated as the gain-powered pilots (GPP) scheme, is proposed for the case in which the CCF is subject to a certain amount of error. The simulation results indicate that the GPP scheme consistently outperforms the EPP method in terms of improving the performance of the linear minimum mean square error (LMMSE) channel estimator.