Mean square error analysis and linear minimum mean square error application for preamble-based channel estimation in orthogonal frequency division multiplexing/offset quadrature amplitude modulation systems
Résumé
In this paper the performance of different preamble-based channel estimation techniques is analyzed for orthogonalfrequency division multiplexing/offset QAM (OFDM/OQAM) modulation systems. Three pilot allocationmethods, the pair of pilot (POP), the interference cancellation method (ICM), and the interference approximationmethod (IAM) are considered. A theoretical expression of the estimation mean square error (MSE) is performedfor each of them, which considers the selectivity of the channel and the interferences from all the neighboringtime-frequency positions. Moreover, an application of the linear minimum mean square error (LMMSE) estimator inOFDM/OQAM is investigated and an analysis of its MSE performance is provided as well. It is shown that, due tothe intrinsic interference, the MSE of the channel estimation inevitably reaches an error floor whatever the appliedmethod is. Numerical results show that the theoretical MSE assessments match those obtained by simulation. Inaddition to the MSE, the bit error rate (BER) performance for the different channel estimators is depicted.