Design of an Adaptive Receiver for OFDM Systems Using Conjugate Transmission

In this paper, we first investigate two efficient inter-carrier interference (ICI) self-cancellation schemes for orthogonal frequency division multiplexing (OFDM) systems, conjugate cancellation (CC) and phase-rotated conjugate cancellation (PRCC), by examining their system structures and performances. Then, we propose an adaptive receiver design based on conjugate transmission for ICI self-cancellation in OFDM systems. Compared to PRCC, the proposed receiver not only saves the signaling overhead by omitting the need to feed the frequency offset estimate back to the transmitter, but also has the frequency tracking capability by adopting the normalized block least mean-squared algorithm in the update process for the artificial phase rotation factor. Computer simulations show that the proposed scheme can provide better bit-error-rate performance over both CC and PRCC. Besides, even if the frequency offset estimation error is considered, the proposed scheme is shown to be more robust than the other methods.