LMMSE channel estimation in OFDM context: a review

International audienceLinear minimum mean square error (LMMSE) is by definition the optimal channel estimator in the sense of meansquare error criterion, but its practical application is limited by its high complexity. Furthermore, the LMMSE estimation methodrequires the knowledge of both the channel and the noise statistics, which are a priori unknown at the receiver. A wide range oftechniques are proposed in the literature in order to overcome these two drawbacks. In this study, the authors give an overviewof the LMMSE-based channel estimation in an orthogonal frequency division multiplexing (OFDM) context. A didactic reminderconcerning the basics of LMMSE estimation and its performance is provided, and a survey of techniques of the literature, whichenable the practical application of LMMSE and the reduction of its complexity, is presented in both single-input single-output andmultiple-input multiple-output contexts. Finally, some perspectives are provided, in particular the application of the LMMSEestimator to flexible waveforms beyond OFDM