Low-Complexity PTS Schemes Using Dominant Time-Domain Samples in OFDM Systems

Partial transmit sequence (PTS) is a probabilistic peak-to-average power ratio (PAPR) reduction scheme for orthogonal frequency division multiplexing (OFDM) signals, but it requires an exhaustive search for the one with the minimum PAPR over all alternative OFDM signal vectors. In order to reduce such computational complexity, it was proposed that the PAPR value of each alternative OFDM signal vector is approximately estimated by using dominant time-domain samples selected based on a simple metric. In this paper, two new effective metrics for selecting dominant time-domain samples are proposed for low-complexity PTS scheme. For further lowering the computational complexity, two low-complexity PTS schemes are proposed by sorting the dominant time-domain samples in decreasing order of their metric values. Simulation results confirm that compared with the conventional PTS scheme, the proposed PTS schemes show identical PAPR reduction performance with substantially reduced computational complexity.

I. Introduction

Orthogonal frequency division multiplexing (OFDM) is an essential technique in modern wireless communication systems due to its bandwidth efficiency and robustness to the multipath fading. Therefore, OFDM has been adopted in various wireless communication systems such as digital video broadcasting (DVB) and IEEE 802.11 wireless local area network (WLAN) [1]. However, high peak-to-average power ratio (PAPR) of OFDM signals results in signal distortion due to the nonlinear effect of high power amplifier (HPA), which causes in-band distortion, out-of-band radiation, and bit error rate (BER) degradation at the receiver.