TDD-CDMA系统中智能天线的应用研究

Research on the SA Application in the TDD-SCDMA System

目前所能找到的与智能天线(SA)应用有关的资料都错误认为:一副SA可以在一个载波上同时实现多个CDMA(码分多址)码道的定向发送,可以利用发基带信号非移相加权的方法实现SA发信波束形成。利用SA即相控阵天线定向发射的基本原理证明了以上两种观点的不可实现性。TD-SCD-MA标准和系统中的SA设备是建立在上述两种错误理论基础上的产物,因此它们不可能实现同时隙内多个码道的定向发送,但是它可以利用SA的定向或分集接收作用,因此会形成一个上行容量大于下行容量的奇异系统,与3G标准应该为移动因特网服务的基本要求背道而驰。此外由于使用时分双工方式,基站收发系统只能在一半时间内工作,将使TD-SCDMA设备和能源利用率下降一半。

It is wrongly holded by all the references found on hand about SA application that only one SA can make multiple CDMA channels transmit direetionally on a single carrier synchronously, and SA transmitting beamforming can be realized with weighted transmitting baseband signal without phase shifting. This paper proves that the above two points of view cannot be realized by the basic principle of SA-the phase array antenna with the feature of direetionally-launching. TD-SCDMA standard and the system with SA are both built on the basis of the above two wrong theories. A strange system will appear in which uplink capacity is larger than that of the downlink, since trasmitting directionally on multiple coded channels synchronously cannot be realized, but it can make use of the directional or diversity reception of SA,whieh is opposite from that the 3G standard should serve for mible intemet. Additionanlly,the transceiver equipment in BS for TD-SCDMA cannot work synchronously so that the utilization of the equipment＆ energy will drop half.