A 16-QAM signal X, whose power is normalized as unity, is transmitted with OFDM over the discrete-time channel model h which has been used in Homework #2 and #3. As depicted in the below figure, the transmitter (TX) is now equipped with an N-point ID

在信号频谱分析中，可以通过平均方法消除噪声，而存在多种频谱平均方法。(In the signal spectrum analysis, the noise can be eliminated by averaging, and there are many spectral averaging methods.)