IQ不平衡的OFDM系统信道估计和补偿技术研究
关键词 正交频分复用 IQ不平衡 频域 时域 信道估计 补偿
Title Channel Estimation and Compensation Schemes of OFDM Systems with IQ
Imbalances
Abstract
Orthogonal frequency pision multiplexing (OFDM) owns a high spectrum efficiency
and a good ability to combat multi-path interference and has been regarded as one of
the core technologies of the future wireless communications. Compared with the super
heterodyne receiver, the zero-IF receiver has lower price and lower power consumption
and has been widely used in OFDM systems. But it suffers from IQ imbalance which
can cause a significant degradation in the bit error rate (BER) performance of wireless
communication system. This paper focuses on the study of OFDM systems with IQ
imbalances at both the transmitter and receiver，the main work is as follow: 1) The
frequency-domain (FD) least-square (LS), the time-domain (TD) LS and the Gaussian
eliminate (GE) channel estimation are used to estimate the channel parameters. The
analysis and the simulation show: the FD-LS improves the estimation performance at
the expense of increasing the training symbols and it requires at least 16 training
symbols in order to achieve the performance of ideal IQ channel estimation; the TD-LS
fully exploits the characteristics of time-domain channel and make improvement on the
basis of the FD-LS and the GE designs special pilot signal. The TD-LS and GE require
only two training symbols to achieve an ideal channel estimation performance. 2) The
FD-LS and GE compensation algorithms are adopted to eliminate IQ imbalance and the
simulations show that the latter has lower complexity and lower SNR loss than the
former.
Keywords OFDM IQ Imbalance frequency-domain time-domain channel
estimation compensation.
目 次
1 绪论 .. 1
1.1无线通信概述 .. 1
1.2研究背景及意义 . 2
1.3 OFDM技术的发展及 IQ不平衡的原因 .. 2
1.4国内外研究现状 . 3
1.5论文结构和内容 . 4