FBMC/OQAM系统导频辅助信道估计方法概述

Survey of pilot-aided channel estimation in FBMC/OQAM

滤波器组多载波/交错正交幅度调制(filter bank-based multicarrier/offset quadrature amplitude modulation,FBMC/OQAM)是一种基于滤波器组的多载波调制系统,其在收发器两端采用特殊的信号处理机制来消除符号间/载波间存在的固有干扰,具有旁瓣衰减快和无需严格正交同步等优点。但是在信号传输过程中,这种固有干扰与信道特性叠加,严重影响了导频位置的信道估计精度。描述了FBMC/OQAM的系统框图、正交特性,并对其固有干扰作了时频域定量分析。指出将正交频分复用(orthogral frequency division multiplexing,OFDM)系统信道估计方法应用到FBMC/OQAM系统的关键是处理好固有干扰项。将现有FBMC/OQAM导频辅助信道估计方法分为干扰消除、干扰利用和干扰规避三大类,并从导频宽度、计算复杂度和估计性能等方面,对3类信道估计方法进行比较,指出各自的优缺点。概述了当前最新的创新性研究方法,并提出未来的工作重点。

FBMC/OQAM is a muhicarrier modulation technique based on fiher banks, which uses cooperative signal processing mechanisms on transmitter and receiver separately to eliminate the inherent ISI （inter-symbol interference） and ICI （inter-carrier interference）. Indeed, FBMC/OQAM is characterized by high spectral containment and non-strict orthogonal in the context of multicarrier modulation. In the process of signal transmission, however, the inherent interference and channel response coexist on pilot position, which deeply degrades the performance of channel estimation. This paper firstly describes the systematic diagram and orthogonal property of FBMC/OQAM, and makes a quantitative analysis in time-fre- quency domain for the intrinsic interference, which summarizes that the key for channel estimation in FBMC/OQAM is to deal with the intrinsic interference. Furthermore, most of existing pilot-aided channel estimation methods are investigated in terms of interference-cancellation, interference-approximation and interference-avoidance, and then their comparisons are made from the pilot width, computational complexity and the performance, etc. Finally the summarization of some latest in- novations and the possible future research issues are presented.