Because capacity of channel is limited by interference. Especially for the interference from the same channels and the adjacent channels.
由于信道的容量是由干扰所限定的，尤其是同信道干扰和邻信道干扰的影响更为严重。
2
It is very important problem to achieve adjacentchannel duplex in radio communication, that result in to eliminate the large signal blocking interferencefrom local transmitter in reciever.