Paper 205, ENG 105 Simulink-based Simulation of Quadrature Amplitude

Adaptive modulation system is one of the key techniques in building a broadband mobile communication network because of increasing shortage of wireless communication channels. Quadrature amplitude modulation (QAM) has been widely used in adaptive modulation because of its efficiency in power and bandwidth. To better understand the QAM system, a Simulink-based simulation system is designed. In the paper, the theory of M-ary QAM and the details of the simulation model are provided. In the simulation model, the parameter settings for random generator, QAM modulation and demodulation, AWGN wireless channel are provided. Error rates of QAM system versus the signal-to-noise ratio (SNR) are used to evaluate the QAM system for adaptive modulation. The model can be used not only for the criteria for adaptive modulation but also for a platform to design other modulation systems