4G移动通信标准TD-LTE与FDD-LTE的区别是（ ）。
- A.频率的利用方式不同
- B.划分上下行信道的方式不同
- C.采用的调制方式有区别
- D.拥有专利技术的厂家不同
正确答案及解析
正确答案
解析
LTE FDD采用的是频分双工，TD-LTE则是时分双工。
FDD是在分离的两个对称频率信道上进行接收和发送，用保护频段来分离接收和发送信道。FDD必须采用成对的频率，依靠频率来区分上下行链路，其单方向的资源在时间上是连续的。FDD在支持对称业务时，能充分利用上下行的频谱，但在支持非对称业务时，频谱利用率将大大降低。
在TDD方式的移动通信系统中， 接收和发送使用同一频率载波的不同时隙作为信道的承载， 其单方向的资源在时间上是不连续的，时间资源在两个方向上进行了分配。某个时间段由基站发送信号给移动台，另外的时间由移动台发送信号给基站，基站和移动台之间必须协同一致才能顺利工作。
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