Performance comparison of trellis-shaped OFDM systems over nonlinear channels

Orthogonal frequency-division multiplexing (OFDM) can achieve remarkable performance in terms of spectral efficiency, but its power amplifier (PA) efficiency becomes poor because of its high peak-to-average power ratio (PAPR) nature of transmitted signals. Trellis shaping (TS) is an effective method to reduce PAPR without signal distortion. Several metrics are developed for TS to achieve efficient PAPR reduction in the literature. In many practical OFDM systems, however, slight peak clipping at PA is acceptable. This causes nonlinear distortion that may degrade bit error rate (BER) performance as well as yield out-of-band radiation of transmitted signal power. In this paper, we make a performance comparison of trellis-shaped OFDM systems with different metrics in terms of BER and resulting power spectrum in a practical scenario where the signal is clipped by PA.