A new 'constant-amplitude' architecture for MQAM transmission

Constant-amplitude transmitter architectures offer high amplification efficiencies by using one or more nonlinear amplifiers. In this article, we propose one new such architecture, dubbed DbPSK, for efficient MQAM transmission. The proposed architecture decomposes the MQAM constellation into two pseudo-MPSK constellations that are independently amplified, with high efficiency nonlinear amplifiers, then combined to generate the original MQAM signal amplified. We show that the proposed architecture provides interesting performance in terms of power, efficiency and linearity for any MQAM signal transmission and we discuss its implementation aspects. This architecture can be considered as an improvement of the NLA-QAM architecture used in satellite applications.