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双向全双工中继系统自干扰抑制巩玉林;周成杰【摘要】As a key technology of 5G,Full-Duplex Relay (FDR) technology with its advantages of frequency reuse is concerned by the industry. FDR not only can improve the system capacity but also be used at very low cost to expand coverage. However,the characteristics of simultaneously sending and receiving signals of the same frequency result in serious self-interference of loop,which is a major factor restricting the development. For the core issue,Self-Interference Cancellation (SIC),in FDR system,the method of special domain is used to eliminate interference in MIMO in order to reduce the bit error rate and improve the system capacity. FDR is combined with bidi-rectional communication to establish bidirectional full-duplex relay system model. The encoder and decoder of relay nodes is designed based on original zero space projection,and time-domain method is applied to eliminate interference from the source node receiving end. Theoretical analysis and simulation results show that this model can effectively eliminate the bidirectional FDR system self-interference, greatly improving system performance.%作为5G的关键技术,全双工中继(Full-Duplex Relay,FDR)技术凭借其频率复用的优势而备受业界关注。
全双⼯通信中的⾃⼲扰消除技术学位论⽂中国科学技术⼤学本科毕业论⽂题⽬全双⼯通信中的⾃⼲扰消除技术英⽂The Technology of Self-Interference Cancellation in Full Duplex Communication⽬录摘要 (2)第⼀章引⾔ (3)1.1 背景资料 (3)1.2 选题意义 (6)1.3 我的任务 (7)第⼆章⽆线传输技术综述 (8)2.1 ⽆线传输的历史及发展 (8)2.2 TDD和FDD (9)2.3 CDMA (14)2.4 同时同频全双⼯ (16)第三章天线⼲扰消除 (19)3.1 天线消除原理 (19)3.2 天线消除效果 (20)3.3 ⼩结 (31)第四章射频⼲扰消除 (31)4.1 射频消除概念 (31)4.2 射频消除效果 (32)第五章数字⼲扰消除 (33)5.1 数字消除原理 (33)5.2 数字消除理论推导 (33)5.3 数字⼲扰消除分析与⼩结 (38)第六章结束语 (38)参考资料 (39)致谢 (41)摘要要实现全双⼯通信，要克服诸多困难，其中最主要的瓶颈就是收发机的⾃⼲扰问题。
当发射机发送某个信号时，其中的部分能量会被⾃⾝的接收装置接收到。
如果正好发送与接收信号同频率，就会产⽣⼲扰。
并且由于信号源离⾃⾝的接收机很近，所以⾃⼰发射出去的信号能量可能会⽐接收到的信号能量⼤，甚⾄⾼达100dB以上。
为了能正确解码所需要接收的信号，就要求我们的⾃⼲扰消除性能⾄少达到100dB。
⽬前世界上所研究的都是多级消除，即天线⼲扰消除、射频⼲扰消除、数字⼲扰消除等来达到更好的消除性能。
其中天线⼲扰消除⼀般可达40+dB，射频域和数字域⼲扰消除均可达30+dB，已能初步满⾜实验条件下的全双⼯通信。
关键词: 全双⼯、⾃⼲扰、⼲扰消除AbstractTo achieve full-duplex communication must overcome many difficulties, and what the most important is the self-interference of transceiver. When a transmitter transmits a signal, part of the energy will be received by the itself. If you send and receive signals exactly the same frequency will cause interference. Since the signal source and the receiver are placed close, the signal transmited by itself may be stronger than the received signal, even up to more than 100dB. In order to correctly decode the received signal, it is required that the performance of interference achieve at least 100dB. The study of the world are multi-stage elimination, such as antenna interference cancellation, RF interference cancellation and digital interference cancellation to achieve better elimination. Which antenna interference cancellation generally up to 40 + dB, and the interference cancellation of RF domains and digitaldomains can be up to 30 + dB, has been able to meet the initial full-duplex communication under experimental conditions. Keyword：full-duplex , self-interference , interference cancellation第⼀章引⾔1.1 背景资料从烽⽕狼烟到现在的移动⽆线设备，⼈类的通信⽅式发⽣了质的飞跃。
MIMO—OFDM系统ICI自消除改进算法MIMO-OFDM系统是一种同时使用多天线和正交频分复用（OFDM）技术的通信系统。
由于信号在多路径衰落环境中传播时会导致干扰，因此在MIMO-OFDM系统中会出现信道间干扰（ICI）问题。
为了解决ICI问题，可以采用ICI自消除的改进算法。
ICI自消除算法可以通过对接收信号进行预处理来减小ICI干扰。
以下是一种可能的ICI自消除改进算法：1.估计信道响应：通过发送已知的参考信号，接收端可以估计各个子载波上的信道响应。
这种估计可以使用最小二乘法、贝叶斯估计等方法进行。
2.时频域上的ICI补偿：根据信道响应估计结果，可以构造出ICI的补偿矢量，并将其应用于接收信号上进行ICI消除。
补偿矢量可以通过信道响应与接收信号频谱之间的相关性来计算得到。
3.时域上的ICI自消除：对于每个子载波，可以根据时域上的ICI干扰对接收信号进行补偿。
具体而言，可以使用循环前缀（CP）的一部分来估计ICI干扰并进行补偿。
4.突发干扰抑制：突发干扰是指短时干扰信号，会对ICI自消除产生干扰。
为了抑制突发干扰，可以引入自适应滤波器来对ICI自消除信号进行滤波。
5.迭代优化：将ICI自消除算法与信道估计算法相互迭代优化，可以提高ICI自消除的效果。
例如，在估计信道响应时使用已经ICI自消除的信号，再将得到的信道响应与接收信号进行时频域上的ICI补偿等。
该改进算法可以有效提高MIMO-OFDM系统中ICI自消除的效果，并减小系统的误码率。
然而，算法的设计和实现要考虑到计算复杂度的限制，以及系统的实际使用环境。
因此，在实际应用中，需要根据具体情况进行优化和调整。
一种MIMO中继系统的自适应自干扰消除方法刘剑飞;戎乾;王蒙军【摘要】Full-duplex relays simultaneously receive and transmit at the same frequency for saving frequen-cy resource,thus the undesired feedback from the transmitting antennas to receiving antennas is created by the radio echoes at the same time for the lack of isolation between antennas. Based on an adaptive steepest descent algorithm,the self-interference cancellation scheme is presented to solve the problem of self-inter-ference for the full-duplex broadband multiple-input multiple-output( MIMO) relays. The characteristics of self-interference echo channel are estimated by the feedback signals from the output of relay,and then an estimated signal is generated to suppress self-interference echo to a tolerable level. The simulation re-sults show that the scheme is obviously effective on the filter tracking performance,convergence distribution and mean squared error( MSE) for different MIMO configurations.%为节省频率资源，全双工中继一般采用相同的频率接收和发射信号。
