Influence of imperfect reciprocity on MAP-based automatic modulation classification for adaptive OFDM systems in TDD mode

Abstract:
In this contribution, the influence of channel time-variance, channel estimation errors and non-reciprocal transceivers on a reciprocity-based automatic modulation classification (AMC) algorithm for adaptive orthogonal frequency division multiplexing (OFDM) transmission systems in time-division duplex (TDD) mode is analyzed. By applying a well-known relative calibration method, it is shown by simulations of the classification error probability that the performance degradation of the AMC method caused by the assumed imperfections can be kept small. In the considered indoor propagation scenario, the proposed transmission scheme with bit loading (BL) at the transmitter and AMC at the receiver outperforms a non-adaptive scheme in terms of the effective bandwidth efficiency and is superior to a signaling-based concept.