循环前缀不足异步协作系统中继非线性预编码  

Relay No-linear Precoder in Asynchronous Cooperative Systems with Insufficient Cyclic Prefix

作　　者：刘萍[1] 黄学军[1] 

机构地区：[1]南京邮电大学通信与信息工程学院,江苏南京210003

出　　处：《计算机技术与发展》2015年第3期193-196,共4页Computer Technology and Development

基　　金：国家"973"重点基础研究发展计划项目(2013CB329005);国家科技重大专项(2012ZX03001008-003;2011ZX03005-004-03);江苏省自然科学基金重点专项(江苏"973")(BK2011027)

摘　　要：在异步协作OFDM通信系统中,正交频分复用(OFDM)技术用于对抗各中继节点到目标节点的时延干扰。各中继节点到目标节点的信道可以被看作多径信道,当循环前缀(CP)的长度大于等于中继时延长度时,可以有效地避免时延引起的符号间干扰(ISI)。实际上协作通信时延多变且与特定情景有关,时延无法被预先知道,同时加入循环前缀降低了码元传输速率,所以有必要研究缩短CP情况下的异步协作OFDM传输方案。但是,当CP长度小于时延长度时,符号间干扰无法被完全消除。为了解决这个问题,文中设计了一种中继节点非线性预编码方案。仿真结果表明,中继节点非线性预编码方案能够很好地降低误码率,提高系统带宽利用率,并且中继节点非线性预编码方案性能优于接收端采用判决反馈均衡的方案。In the asynchronous cooperative OFDM system,Orthogonal Frequency Division M ultiplexing（ OFDM） technology is applied to combat the time delays from the relay nodes. Channel from relay nodes to the destination node are treated as multipath channel,when the Cyclic Prefix（ CP） is not less than time-delay length,Inter-Symbol Interference（ ISI） caused by the time delay can be effectively avoided. Actually,the time delays from relay nodes may vary and depend on a particular scenario in a cooperative system,thus time-delay cannot be know n in advance,and adding cyclic prefix will reduce code transmission rate. Therefore,it is necessary to research transmission scheme for asynchronous cooperative OFDM system with insufficient CP. However,when the CP length is less than the length of the time-delay,inter-symbol interference cannot be completely eliminated. In order to solve this problem,design a scheme of no-linear precoder in relay node. Simulation results show that the scheme of no-linear precoder in relay node can significantly low er bit error rate,improve the utilization rate of system bandw idth,and prove the performance of the scheme is better than the scheme of decision feedback equalizer in receiver.

关 键 词：异步协作OFDM通信系统 循环前缀 非线性预编码 时延 

分 类 号：TP302[自动化与计算机技术—计算机系统结构]