Dynamic analysis of adaptive modulation in wireless communications

The research area in this thesis investigates the problem of adaptive modulation from a system dynamic analysis point of view. The mathematical model of a transmission system using quadrature amplitude modulation is established to describe the system dynamic in terms of the transmission rate (constellation size), transmit power and the bit error rate that correspond to the instantaneous channel gain. With appropriate design of a feedback controller, it has maximized the spectral efficiency of the channel for a required bit error rate for an acceptable quality of service. This research contributes to optimized usage of the limited frequency spectrum for wireless applications.