In this chapter, the conceptof Adaptive Quadrature AmplitudeModulation (AQAM) is introduced, whereby the modulation mode is adapted at the transmitter on a burst by burst basis. This adaptation is implemented based on thereceiver’s perceived channel qualityand its main BER. motivation is to maximise the transmission throughput at a given target In our investigations AQAM is initially applied in a narrow-band environment in conjunction with power control, where the transmitted power is only varie