Orthogonal pilot sequences for peak-to-average power reduction in OFDM

In this paper, a new peak-to-average power reduction approach for OFDM has been addressed. Two-Dimensional Pilot-Symbol Assisted Modulation (2D-PSAM) is employed in coherent OFDM for channel estimation and it is based on inserting known symbols spreaded out throughout the 2D time-frequency grid. We show that these scattered symbols can also be employed to perform distortionless peak power reduction. To reduce additional system complexity and side information, a finite set of orthogonal pilot sequences is proposed, and also blind detection can be performed without prior knowledge of redundancy at the receiver.