针对STTD的均衡器结构推导

主要推导双天线STTD发送分集下在HSDPA下行链路开环中的均蘅器结构。第三代移动通信系统为了增加容量而在前向连接中采用了多种分集技术。包括应用在3GPP2标准中正交传输分集（OTD）和空时扩频（STS），另外空时传书分集作为3GPP传输标准的一部分。这3种分集是为了达到最小均方误差。在多径衰落信道下，均衡器能够显著改善系统的性能。但是普通意义下针对单天线的均衡在STTD分集方式下对性能的改善有限。

Derivation of Equalizer Structure for STTD

The paper mainly discusses the equalizer structure for Space-Time Transmit Diversity in open-looped HSDPA downlink system.Several transmit diversity methods have been introduced into the base-to-mobile(forward) link of third generation(3G) standards in responsetoa need for capacity increasing.Orthogonal transmit diversity(OTD) and space-time spreading(STS) have been included in the 3GPP2 standard,while space-time transmit diversity (STTD) is one part of the 3GPP standard.All three of these transmit diversity methods are used to get the minimum mean-squared error.In multi-path frequency selected channel,the equalizer can remarkably improve system performance,but the equalizer for single antenna applying in STTD can only improve system performance a bit.