Power efficient coded 16-OQAM schemes over nonlinear transmitters

High power and spectral efficiencies are crucial on modern wireless communications. M-QAM (Quadrature Amplitude Modulation) modulations have been adopted on HSDPA (High Speed Downlink Packet Access) and satellite links, due his higher spectral efficiency. However, due to large envelope fluctuations levels, nonlinear operations such as an high power amplification are undesirable since can they lead to performance degradation and spectral widening. Nonlinearly coded M-OQAM (Offset Quadrature Amplitude Modulation) modulations can be viewed as a particular case of nonlinear OQPSK signals (Offset Quadrature Phase Shift Keying) when the pulse modulation is designed to take advantage from the nonlinear format. In this paper we present nonlinearly encoded 16-OQAM schemes, based on two nonlinear OQPSK signals, designed to allow higher amplification efficiencies due its robustness against nonlinear distortions. The proposed approach assures an higher robustness against nonlinear effects, namely spectral regrowth and performance degradation. The consequences are improved performances over several drive operations of nonlinear amplifiers and a better compromise between bandwidth and power efficiencies. As we can see further the posted simulation results support our assumptions.