机构地区: 韶关学院计算机科学学院
出 处: 《重庆邮电大学学报(自然科学版)》 2013年第3期292-299,共8页
摘 要: 在高速移动环境下,基于正交频分复用(orthogonal frequency division multiplexing,OFDM)的长期演进(longterm evolution,LTE)移动通信系统受信道快速时变引起的多普勒频偏影响,产生子载波间干扰(inter-carrier-interfer-ence,ICI),严重破坏系统性能。ICI成为LTE技术在高速移动场景下应用的一个难点。在分析多普勒频偏及ICI成因的基础上,总结国内外通过编码自消除、均衡、迭代判决反馈消除、时域快变信道估计等方法消除高速移动引起的OFDM系统ICI的主要方法,分析并指出现有方法存在的问题。在此基础上,介绍了最新提出的OFDM频域快变信道估计的思想。报道了LTE上、下行链路正交频分多址接入系统中相关问题的研究情况,并对后续的研究工作提出了展望。 Under highly mobile environments ,the performance of long term evolution (LTE) based on orthogonal frequency division multiplexing (OFDM) can be destroyed by inter-carrier-interference (ICI) caused by the time varying channels' Doppler shills. ICI is a difficult point of LTE in highly mobile environments. The cause of Doppler shifts and IC] are intro- duced firstly. ICI mitigation techniques of OFDM over highly mobile environments are reviewed such as data encoding sell" 1CI cancellation, equalization techniques, iterative interference cancellation and time domain time-varying channel estimation etc. Existing problems of such methods are analyzed and the new proposed frequency domain time-varying channel estima- tion is introduced. Finally, related work for LTE uplink/downlink systems were reported and directions for following re- search is pointed out.