This dissertation introduced the development of mobile communication firstly , then given out the key technology of next generation communication , discussed the promising diversity technology . mimo and stbc is given out in the next chapter , simulation results proved the benefitial of mimo and stbc . some channel estimation methods are introduced subsequently , the channel estimation method based on orthogonal design is proved better than ls ( least square ) algorithm 本文就是以这一背景而展开的。本文以移动通信发展的历程为开端,介绍了下一代移动通信中的关键技术,重点介绍了将会得到广泛应用的分集技术,接着给出了下一代移动通信系统中将广泛应用的mimo技术和空时编码技术,仿真结果证明了该技术将会带来显著的性能增益。
Space - time coding technology is based on multi - elements antenna array and has strong points of both time processing and space processing . it can satisfy the requirements of high data rate transmission in the future radio mobile system without the increase of the transmitting power and the spread of the frequency . and it can greatly improve the quality of communication services and system capacity under fading channels 空时编码技术是一种利用多天线阵发送和接收的技术，该技术能很好地结合时间处理技术和空间处理技术的特点，能在不增大发射功率和不扩展频带的前提下满足未来无线移动通信对高数据率传输的要求，从而全面提高衰落信道的通信质量和通信系统容量。
As a combination of ofdm with space - time coding technique , mimo - ofdm becomes more and more important in the future wireless communication systems , the mimo - ofdm system can not only effectively enhance the transmission rate and capacity of the wireless communication system but also greatly mitigate the effections of mufti - path fading and interfere Mimo - ofdm技术将ofdm与空时编码技术有机的结合在一起,能够大幅度的提高无线通信系统的信道容量和传输效率,并能有效的抵抗多径衰落、抑制干扰和噪声。
Concatenated convolutional coding ( ccc ) is key technology in channel coding , which can provide near shannon bound performance . space - time coding ( stc ) combines signal processing at receiver with coding techniques appropriate to multiple transmit antenna and provides significant gain . this dissertation examines concatenated convolutional coding and space - time coding 级联卷积编码是目前信道编码领域研究的热点，它能够提供接近shannon极限的性能；而空时编码将多个发射天线的编码技术和接收端的信号处理结合在一起，能够得到很高的增益。
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。
The research on df ( decode - and - forword ) cooperation scheme is proposed aferwrds by analysis and simulation , compared with the af scheme in performance and application . at last after research on cc ( coded cooperation ) cooperation scheme , including original cc and space - time cc , an adaptive space - time coded cooperation scheme , which could more efficiently ultilize the resource of cooperation users , is propsed . simulation results have proved the proposed scheme has better performance than space - time cc both in bit error rate and system throughput 最后在对编码前传( cc , codedcooperation )协同分集方式中的普通编码协同和空时编码协同的原理和实现方式进行研究的基础上提出了一种基于空时编码协同的对信道具有自适应能力的自适应空时编码协同方法,并分析了这种方法的优越性,通过计算机仿真证明了新方法带来的误码率性能的改善和系统吞吐量的提升。
Researches on the space - time code have been under the assumption of independent fading and perfect channel state information . but in a realistic system , the above assumption is very difficult to be acquired . based on this , the performance of space - time code under correlated rayleigh fading channel and rician fading channel is studied in thispaper 在实际的传播环境中,不同天线上的信号的衰落在空间上存在相关性,研究了瑞利相关衰落信道的空间相关性对空时编码性能的影响以及相关莱斯衰落信道下空时编码系统的性能,以期推动空时编码在无线通信系统中的实际应用。
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。
Because using ofdm , a frequency - selective fading channel can be transformed into multiple frequency - flat fading sub - channels , in the coding process , spatial diversity ( due to multiple antennas ) is integrated with frequency diversity ( due to delay spread ) , therefore , the proposed code can provide higher diversity gain than space - time code alone 该编码利用正交频分复用把频率选择性衰落信道变换成平衰落信道的特性，同时引入了基于多天线的空间分集和基于时延扩展的频率分集，比空时编码具有更高的分集增益。
The assumption that the channel is known is questionable in a rapidly changing mobile environment , or when multiple transmitter antennas are employed . unitary space - time codes and differential unitary space - time codes do n ' t need any channel information . we discuss the unitary space - time codes briefly and study the details of the dustc , including the fundamental differential transmission and receiver equation , and parameters searching algorithm . the parameters searching and simulations results is proposed 酉空时编码及酉差分空时编码( dustc )都不需要信道信息,着重研究了酉差分空时编码技术,简要说明了酉空时编码的信号形式及星座设计方法;分析了dustc的发送和接收公式,分析了dustc的严格pep和sep的联合界,给出了当snr值在不同的范围时, dustc星座参数的选取准则,并进行了rayleigh衰落信道的仿真。
