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

In this study, the performance of different preamble-based channel estimation techniques is analysed for orthogonal frequency division multiplexing/offset quadrature amplitude modulation (OFDM/OQAM) modulation systems. Three pilot allocation methods, the pair of pilot, the interference cancellation method, and the interference approximation method are considered. A theoretical expression of the estimation mean square error (MSE) is performed for each of them, which considers the selectivity of the channel and the interferences from all the neighbouring time-frequency positions. Moreover, an application of the linear minimum MSE estimator in OFDM/OQAM is investigated and an analysis of its MSE performance is provided as well. It is shown that, due to the intrinsic interference, the MSE of the channel estimation inevitably reaches an error floor whatever the applied method is. Numerical results show that the theoretical MSE assessments match those obtained by simulation. In addition to the MSE, the bit error rate performance for the different channel estimators is depicted.