IDMA迭代检测设计-通与信息系统专业毕业论文.docx

摘要4．利用C语言完成了TDR．IDMA系统的部分性能仿真，并且完成了在两用 摘要 4．利用C语言完成了TDR．IDMA系统的部分性能仿真，并且完成了在两用 户情况下IDMA接收端的FPGA的硬件实现，同时给出了TDR．IDMA系统接收端 的硬件实现结构。 关键词： IDMA系统，Turbo码，交织器，时间反转技术，迭代检测 ．Ⅱ． AbstractABSTRACT Abstract ABSTRACT Multiple-Access is one of the key technologies in wireless communication area． There are three main Multiple-Access techniques，FDMA(Frequency Division Multiple—Access)，TDMA(Time Division Multiple-Access)and CDMA(Code Division Multiple-Access)．All these techniques car／be used solely or mixed with one another． The purpose of these techniques is to get much more Multiple-Access competence within the limited Time-Frequence source． Interleave。Division Multiple Access(IDMA)is proposed by Prof．Li Ping coming from City University of Hong Kong．It originates from CDMA，hence many advantages are inherited from CDMA，in particular,diversity against fading and mitigation of the worst-ease other-cell user interference problem．Verdu and shamai’S research indicates that when a lot of users communicate simultaneously,the lower code rate is used．the better performance Can be got which is dosed to the theory Shannon limitation． Camparing to CDMA，IDMA gets rid of the special spread sequence and uses random interleavers to separate different users．It USeS lOW rate code which Call combine coding and spreading efficiently．At the user end，IDMA adopts a very simple chip—by-chip iterative TURBO MUD strategy．The normalized MUD cost(per user)is independent on the number ofusers． The use of iterative detection can improves system performance greatly,but on the other hand，the number of iteration is one of the bottlenecks of IDMA．Under situations where hi出communication speed is required，the detection time could be too long to be accepted，Also as more iteration numbers are used，the more consumption on resources are needed．These weaknesses can greatly lirnit the use of IDMA． In this paper,we aim to settle the problems proposed above without performance sacrifice．The main WOrks are 1isted bellow： 1．Ana