HDL-based Realization of a 16-QAM Modulator with Sine/Cosine Carrier Generation and Symbol Mapping

This article describes the design and simulation of a 16-Quadrature Amplitude Modulation (16-QAM) modulator in Verilog Hardware Description Language (HDL), and its functional verification were performed in the Model Sim simulation environment. 16-QAM is one of the more commonly used digital modulation types and combines amplitude and phase modulation to enable four bits per symbol transmission to ultimately offer better spectral efficiency. The process uses digital symbol mapping, I/Q separation into the components they represent, and carrier modulation using orthogonal sine and cosine waveforms. The modulator designed is intended for FPGA-based systems and is suitable for high-speed digital communications purposes. The simulation results verified the functions of symbol mapping, waveform generation, guaranteed performance, and the output patterns were sufficiently similar. The architecture represents a basic building block for hardware-based communication systems and can be implemented to extend support for other higher-order QAM schemes or to be integrated/combined with channel models and demodulators for end-to-end system building and expansion.