A Semi-Blind SLM Scheme for PAPR Reduction in OFDM Systems With Low-Complexity Transceiver

A semi-blind selected mapping (SLM) scheme with low-complexity transceiver is addressed for peak-to-average power ratio (PAPR) reduction in orthogonal frequency-division multiplexing (OFDM) systems. In the proposed scheme, the phase rotation vectors for the data vector and those for the pilot vector in an OFDM symbol are separately designed, which enables both low computational complexity and embedding of the side information (SI) into the pilot subcarriers at the transmitter. To implement data detection at the receiver, pilot-aided embedded SI detection algorithm is introduced, and a low-complexity suboptimal SI detection algorithm is also proposed. Analysis and simulation results show that the proposed scheme can achieve much lower computational complexity than that of the available semi-blind SLM schemes at both the transmitter and receiver, whereas it has slightly worse PAPR reduction performance and almost the same bit error rate (BER) performance, even with the suboptimal SI detector, as compared with the conventional SLM (C-SLM) with perfect SI at the receiver.

I. Introduction

Orthogonal frequency-division multiplexing (OFDM) signals suffer from the serious drawback of high peak-to-average power ratio (PAPR). Among all the existing techniques that have been proposed to reduce the PAPR in OFDM systems, selected mapping (SLM) [1]– [6] is among the most attractive ones due to its high performance without signal distortion. However, it requires the transmission of critical side information (SI) for correct data decoding at the receiver. The SI, which is the index of the selected phase rotation vector, is traditionally transmitted as several SI bits for every OFDM symbol. In practice, channel coding must be applied to protect the SI since an erroneous detection of the SI will corrupt a whole received OFDM symbol. This further reduces the data rate, makes the system more complex, and increases the transmission delay [7].