Frequency offset estimation in OFDM systems in the presence of IQ imbalance
Frequency offset estimation in OFDM systems in the presence of IQ imbalance
复制标题
DOI：
10.1109/icc.2003.1203986
复制
发表时间：
2002-11
期刊：
影响因子：
--
通讯作者：
S. Fouladifard;H. Shafiee
中科院分区：
文献类型：
--
作者：
S. Fouladifard;H. Shafiee
在ofdm系统中，子载波之间的正交性被发射机和接收机中的载波频率之间的偏移以及混合器中的所谓的iq不匹配所破坏。当单独处理时，存在有效的算法来估计和补偿频偏和智商不平衡。然而，在这两种效应都存在的情况下，这样的算法不会导致对相关参数的有用估计。在本文中，我们提出了一种在智商不平衡情况下估计频偏的新方法。该算法在基于IEEE802.11a规范的无线局域网中设计的ofdm通信系统上进行了测试。仿真结果表明，即使在接收机混频器中存在较大的增益和相位不平衡值时，该频偏估计算法也能很好地工作。当获得频率偏差的估计时，可以应用任何有效的智商不平衡补偿技术。
The orthogonality between sub-carriers in OFDM systems is disrupted by offsets between the carrier frequencies in the transmitter and receiver as well by the so-called IQ mismatch in the mixers. When treated separately, effective algorithms exist for estimation and compensation of frequency offset as well as IQ imbalance. However, with both effects present, such algorithms do not lead to useful estimates of the related parameters. In this paper, we propose a novel technique for the estimation of the frequency offset in the presence of IQ imbalance. The proposed algorithm is tested on an OFDM communication system designed based on the specifications of IEEE 802.11a for wireless local area networks. Simulation results show that the frequency offset estimation algorithm works well even with large values of gain and phase imbalances in the receiver mixer. When an estimate of the frequency offset is obtained, any effective technique for the compensation of IQ imbalance can be applied.