A novel active constellation extension algorithm with low peak power for pilot-aided OFDM systems

The active constellation extension (ACE) technique is attractive for reducing peak power in OFDM systems. It is simple and easy to implement and provides suboptimal gain in peak power reduction. However, its peak power reduction capacity is sensitive to low target clipping ratios. In this paper, we propose a novel ACE algorithm using pilot symbols. In contrast to the existing ACE techniques, our proposed algorithm can reach any desired target clipping level with low complexity, even when the clipping level is set below the initially unknown optimum value. Simulation results are utilized to compare our proposed algorithm with the existing ACE techniques. It is shown that our proposed algorithm provides better peak-to-average power ratio (PAR) reduction performance for low clipping ratios.