箕舌线变步长LMS/F算法数字域自干扰消除研究北大核心CSCD

自干扰消除技术是实现带内全双工(IBFD)通信的重要前提,其中数字域自干扰消除是带内全双工通信系统中硬件复杂度最低、灵活性最高的自干扰消除技术,并且是自干扰消除的最后一道防线。然而,其消除能力仍需提升,主要是如何处理收敛速度和稳态精度之间的平衡,并且还要具备突变信道的自适应能力。文章提出了一种新的全双工系统的数字自干扰消除方法,发射链路采用数字、模拟预失真技术消除功率放大器的非线性失真,使用辅助接收链获取发射链路信号副本,在数字域中利用重构自干扰信号副本消除接收信号残余自干扰信号和功率放大器残余非线性失真,并通过在接收链与辅助接收链之间共用一个振荡器消除部分接收机相位噪声。仿真表明,该方法与已有变步长LMS消除方法相比,在信噪比为5 dB的条件下,能够在提高收敛速度的同时获得优于变步长LMS方法的消除能力。

Research on Self-Interference Cancellation in Digital Domain for Variable Step Size LMS/F Algorithm Based on Tongue-Like Curve

Self-interference cancellation technology is an important prerequisite for the realization of in-band full-duplex (IBFD) communication. Digital domain self-interference cancellation is the least complex self-interference cancellation technology in IBFD communication systems, and is the last line of defense for self-interference cancellation. However, its elimination ability still needs to be improved, mainly how to deal with the balance between convergence speed and steadystate accuracy, and also have the adaptive ability of mutation channel. In this paper, a new digital self-interference cancellation method for full-duplex systems is proposed, in which the transmit chain employs digital and analog predistortion techniques to eliminate nonlinear distortion of the power amplifier, then an auxiliary receive chain is used to obtain a copy of the transmit chain signal, and the reconstructed self-interfering signal copy is used in the digital domain to eliminate the receive signal residual self-interfering signal and power amplifier residual nonlinear distortion, and cancel part of the receiver phase noise by sharing an oscillator between the auxiliary and normal receiver chains. Simulations show that compared with the existing variable-step-size LMS elimination methods, the proposed method can improve the convergence speed and obtain better elimination ability than the existing variable-step-size LMS methods under the condition of a signal-to-noise ratio of 5 dB.