To find out, we asked Andrea Goldsmith, author of the book Wireless Communications.
为了找到这个问题的答案，记者采访了《无线通信》作者安德里亚·戈德史密斯。
Andrea Goldsmith: You can break up the frequency spectrum in some way whether it 's time or frequency or codes so that assign it to users so they don't interfere with each other.
安德里亚·戈德史密斯：人们可以采取某种方式来划分频谱，不管是通过时间、频率或者编码加以划分，然后将频段分配给用户，使他们之间的通话不受干扰。
Andrea Goldsmith: you can break up the frequency spectrum in some way whether it's time or frequency or codes so that you assign it to users so they don't interfere with each other.
安德里亚·戈德史密斯：人们可以采取某种方式来划分频谱，不管是通过时间、频率或者编码加以划分，然后将频段分配给用户，使他们之间的通话不受干扰。
Andrea Goldsmith: There's not enough spectrum to assign every phone in the world its own dedicated channel so we have to reuse the channels and that causes interference between users.
安德里亚·戈德史密斯：由于频谱资源有限，我们很难让每个用户享有特定的频段，只能不断地将它们回收利用，导致用户之间出现通信干扰。
Andrea Goldsmith: There's not enough spectrum to assign every phone in the world its own dedicated channel so we have to reuse the channels and that causes interference between users.
安德里亚·戈德史密斯：由于频谱资源有限，我们很难让每个用户享有特定的频段，只能不断地将它们回收利用，导致用户之间出现通信干扰。
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