I/Q不平衡OFDM系统基于噪声方差门限的信道估计  

Noise variance threshold-based channel estimator for OFDM system with I/Q imbalances

作　　者：徐彦青[1] 王进[1] 孟庆功[1] 未元[1] 束锋[1,2,3] 余海[1] 沈悦[1] 钱玉文[1] 

机构地区：[1]南京理工大学电子工程与光电技术学院,江苏南京210094 [2]东南大学移动通信国家重点实验室,江苏南京210096 [3]南京理工大学近程高速目标探测技术国防重点学科实验室,江苏南京210094

出　　处：《南京理工大学学报》2015年第3期317-322,共6页Journal of Nanjing University of Science and Technology

基　　金：国家自然科学基金(61271230;61472190);中央高校基本科研业务费专项资金(30920130122004);东南大学移动通信国家重点实验室开放课题(2013D02)

摘　　要：为了提高稀疏信道环境下同相/正交(I/Q)不平衡正交频分复用(OFDM)系统的性能,该文提出了一种低复杂度的门限时域最小二乘信道估计算法。该算法通过估计噪声方差确定合适的门限过滤信道响应采样点内的噪声以提高估计精度。仿真结果表明,该文算法估计精度与现有频域和时域最小二乘信道估计方法相比分别提升了6 d B、2 d B,逼近基于压缩感知的时域迭代收缩算法,且计算复杂度低于后者。In order to improve the performance of orthogonal frequency division multiplexing（ OFDM） system with in-phase and quadrature-phase（ I/Q） imbalances in sparse environment,athreshold-based time-domain least square（ TB-TD-LS） channel estimator is proposed with low complexity. In order to improve the accuracy of channel estimation,an approximate optimal threshold is determined according to noise variance to eliminate the noise in sampling points of channel response in the proposed estimator. The simulation result shows that the estimation accuracy of the TB-TD-LS channel estimator is improved 6 d B than that of a frequency-domain channel estimation algorithm,and is improved 2 d B than that of a time-domain channel estimation algorithm,and closes to that of a time-domain least square iterative shrinkage estimator based on compressed sensing. The computation complexity of the TB-TD-LS channel estimator is lower than that of the time-domain least square iterative shrinkage estimator based on compressed sensing.

关 键 词：同相/正交不平衡 正交频分复用 最小二乘信道估计 噪声方差 稀疏信道环境 频域 时域 压缩感知 

分 类 号：TN929.5[电子电信—通信与信息系统]