QAM with quantised power

The communication system, and method and auxiliary device provided with the efficient modulation and demodulation method. The transmitter (100), confirming communication channel power layer and guide groove ratio of the power layer power generation layer ratio. The power level ratio of the limited by the quantization. The quadrature amplitude modulation a map, according to passing through quantization power level than the charging for quantization quadrature amplitude modulation distance. To the quadrature amplitude modulation technique, a signal modulation to the distance quantization, and is launched the receiver (160).