服从频率选择性衰落并且也服从瑞利衰落的信道。-Subject to frequency selective fading and also subject to Rayleigh fading channel.

Channel estimation for Rayleigh frequency selective fading

The increasing need for high data-rate transmissions over time- or frequency-selective fading channels has drawn attention to modulation schemes with high spectral efficiency such as QAM. With the aim of increasing the “diversity order” of the signal