摘要由于全双工技术可以成倍提高通信系统频谱效率，因此最近获得学术和工业界广泛 关注，被认为是未来无线通信最具竞争力的候选技术之一。 全双工 IQ 不平衡正交频分 复用（Orthogonal Frequency Division Multiplexing，OFDM）系统存在 IQ 平衡和全双工双 重干扰，在此双重干扰场景下如何有效地估计信道和抑制干扰成为该系统能否成功通信 关键技术之一。本文针对此系统的信道估计、补偿和导频优化展开研究，主要工作如下：77314

(1)、针对半双工 OFDM 系统，重点研究了存在 IQ 不平衡参数时的两种信道估计算 法：频域最小二乘（Frequency-domain least square，FD-LS）和时域最小二乘（Time-domain least squares，TD-LS）算法。仿真结果表明：调制为 16QAM 与误码率为 10-2 时，同 FD-LS 相比，TD-LS 可以获得 3dB 信噪比增益，实现了更好的误码性能。

(2)、针对全双工 IQ 不平衡 OFDM 系统，设计了最小均方误差信道估计算法，并定 义了训练积矩阵及其条件数。仿真结果显示：训练积矩阵条件数越逼近 1，频域最小均方 误差算法性能越优。

毕业论文关键词 OFDM，IQ 不平衡，全双工，信道估计，最小二乘，条件数

毕 业 设 计 说 明 书 外 文 摘 要

Title Channel estimation and compensation for full-duplex OFDM system with IQ imbalances

Abstract As the full-duplex (FD) can double the spectral efficiency of the communication system, has attracted extensive attention from both academic and industry fields, and is viewed as one of key techniques of the future wireless communications。 There exists two types of interferences IQ-imbalance and FD interferences in FD orthogonal frequency pision multiplexing (OFDM) systems with full-duplex and IQ-imbalance。 In such double-interference scenario, how to make efficient channel estimation and interference compression is n as successful communication is one of the key technologies of the system。 In this paper, we focus on channel estimation, compensation and pilot optimization of such system。 The main work is as follows:

(1)In a half-duplex OFDM system, we make an investigation on two channel estimation algorithms: frequency-domain least squares (FD-LS) and time-domain least squares (TD-LS)。 Simulation results show that the TD-LS can achieve 3dB signal-to-noise ratio gain over FD-LS at 16QAM and bit error rate (BER) = 10-2, and provides a better BER performance。

(2)In a full-duplex OFDM system with IQ imbalance, a linear minimum mean square error (LMMSE) channel estimator is designed, and the training product matrix and its conditional number are defined。 The simulation results show as the conditional number of the training product matrix is close to one, the performance of the proposed LMMSE is improved。

Keywords OFDM, IQ imbalances, full-duplex, channel estimation, pilot design,   least-squares, conditional number

本科毕业设计说明书 第 I 页

目录

1 绪论 1

1。1 研究背景和意义 1

1。2 国内外研究现状与发展 1

1。3 论文结构 3

2 全双工 IQ 不平衡 OFDM 系统简介 4

2。1 OFDM 调制与解调 4

2。2