Space - time codes can be divided into tree mainly parts : bell layered space - time architecture ( blast ) , space - time trellis codes ( sttc ) and space - time block codes ( stbc ) . in this paper , we mainly compare the performance of blast and stbc in many aspects , such as design criterion , transmission rate , diversity gain , diversity combining , bit error rate and channel capacity etc . in this paper , we first respectively analysed the instantaneous received symbol energy - to - noise ratio of v _ blast in the diversity combining methods of maximal ratio combining ( mrc ) , equal gain combing ( egc ) and selective combing ( sc ) Mimo技术核心是空时编码( stc ) 。空时编码主要分为三种:分层空时码( blast ) 、空时格码( sttc )和空时块码( stbc ) 。本文主要对分层空时码和空时块码这两种编码方式在设计准则、传输速率、分集增益、接收合并、比特差错率和信道容量等方面进行了较为详尽的研究。
Compared with other space - time coding technologies , it can obtain well performance without perfect channel state information ( csi ) . in this dissertation , we look forward to improve the performance of the differential space - time system by concatenating it with an outer code and using iterative soft - decision decoding algorithm 差分空时码是一种适合未来3g 4g快变衰落信道的空时编码技术，与一般的空时码不同的是，它的译码不需要信道状态信息，但仍能保持良好的译码性能。
This thesis focuses on transmit diversity and space - time coding techniques and their implements to the 3rd generation ( 3g ) mobile communication systems especially in wcdma . the main contents are as follow : chapter 1 is an introduction of the application background of transmit diversity and 3g standards , and also presents the proposed transmit diversity schemes in wcdma and cdma2000 briefly 本文主要研究的是发送分集和空时码技术和其在第三代移动通信系统主要是wcdma系统中的应用，主要内容如下：第一章首先简单介绍发送分集的应用背景和第三代移动通信系统，并专门对wcdma和cdma2000中的发送分集方案做了说明。
In order to meet to the higher timing precision of the low frequency time - code timing terminal , the applications of dsp ( digital signal processing technology ) in the time service is researched in this paper . the main works and contributions can be summarized as follows : ( l ) the low frequency signal transmission and dsp technology are discussed . according to the system needs , a testing flat of low frequency time - code based on dsp is built up 本论文的工作针对低频时码授时高端用户的定时需求，对数字信号处理( dsp )这一新型技术在该领域应用进行了探索性研究，主要完成和开展了如下工作： ( 1 )研究分析了低频信道和dsp技术，根据系统要求，从硬件上实现了基于dsp芯片的低频时码信号的采集测试平台。
It consists of three main parts : in the first part , we analyse the effect of multipath on code - tracking loops of receivers in spread - spectrum ranging systems . first , we establish the model of received signals with the present of multipath through the presentation of multipath ’ s characters . then , we analyse the theory of delay lock loop ( dll ) , based on which we derive the tracking error of dll caused by multipath 首先通过对多径信号特性的分析得到存在多径时的接收信号模型,然后在对扩频测距系统的延迟锁定环路( delaylockloop )工作原理的分析的基础上,阐明了多径存在时码跟踪环路产生误差的机理。
