Widely Linear Digital Self-Interference Cancellation in Direct-Conversion Full-Duplex Transceiver
Widely Linear Digital Self-Interference Cancellation in Direct-Conversion Full-Duplex Transceiver
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DOI：
10.1109/jsac.2014.2330093
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发表时间：
2014-09-01
影响因子：
16.4
通讯作者：
Valkama, Mikko
中科院分区：
文献类型：
--
作者：
Korpi, Dani;Anttila, Lauri;Valkama, Mikko
本文研究了全双工直接转换无线电收发信机在实际非理想射频组件下工作时的自干扰建模和消除问题。首先，对自干扰信号进行了详细的建模，考虑了最重要的射频缺陷，即发射机功率放大器的非线性失真以及发射机和接收机IQ混频器的幅度和相位不平衡。分析表明，经过真实的天线隔离和射频对消后，接收机数字基带的主要自干扰波形可以通过对原始发射数据进行广泛的线性变换来建模，而不是经典的纯线性模型。这种广泛的线性自干扰波形是发送器和接收器IQ成像的物理来源，不能通过经典的线性数字对消有效地抑制。在此基础上，结合有效的参数估计方法，提出并推导了一种新型的广线性数字自干扰抵消处理方法。大量的仿真结果表明，所提出的广域线性抵消处理的性能明显优于现有的线性解决方案，从而使得在全双工收发机中使用IQ混频的实用低成本射频前端成为可能。
This paper addresses the modeling and cancellation of self-interference in full-duplex direct-conversion radio transceivers, operating under practical imperfect radio frequency (RF) components. First, detailed self-interference signal modeling is carried out, taking into account the most important RF imperfections, namely, transmitter power amplifier nonlinear distortion as well as transmitter and receiver IQ mixer amplitude and phase imbalances. The analysis shows that after realistic antenna isolation and RF cancellation, the dominant self-interference waveform at the receiver digital baseband can be modeled through a widely linear transformation of the original transmit data, opposed to classical purely linear models. Such widely linear self-interference waveform is physically stemming from the transmitter and receiver IQ imaging and cannot be efficiently suppressed by classical linear digital cancellation. Motivated by this, novel widely linear digital self-interference cancellation processing is then proposed and formulated, combined with efficient parameter estimation methods. Extensive simulation results demonstrate that the proposed widely linear cancellation processing clearly outperforms the existing linear solutions, hence enabling the use of practical low-cost RF front ends utilizing IQ mixing in full-duplex transceivers.