Theory and Applications of Active Constellation Extension

Active constellation extension (ACE) was originally developed to reduce the peak-to-average-power ratio (PAPR) in orthogonal frequency division multiplexing (OFDM) systems with quadrature amplitude modulation (QAM). Alternatively, ACE can be a promising approach for optimizing various possible aspects of the 2-D constellation signals. However, the literature lacks a rigorous theoretical framework for ACE, and hence its applications are currently limited. This study proposes a formal mathematical framework and theory for ACE for the general case of the 2-D constellation signals. The proposed framework is used to demonstrate the roles of ACE in reducing the PAPR in the OFDM systems with QAM and improving the error performance and throughput of phase shift keying under fading channels.