Theoretical Investigation and Optimization of Power Amplifier Nonlinearity for In-Band Full-Duplex Radios
Theoretical Investigation and Optimization of Power Amplifier Nonlinearity for In-Band Full-Duplex Radios
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DOI：
10.1109/twc.2022.3217765
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发表时间：
2023-05
影响因子：
10.4
通讯作者：
Kazuki Komatsu;Yuichi Miyaji;H. Uehara;T. Matsumura
中科院分区：
文献类型：
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作者：
Kazuki Komatsu;Yuichi Miyaji;H. Uehara;T. Matsumura
虽然带内全双工（IBFD）通信理论上可以比传统无线通信技术提高一倍的频谱效率，但如果不降低高功率自干扰（SI）信号就无法实现。由于SI信号受到其自身终端的射频(RF)电路的非线性失真的影响，因此已经积极开发了能够消除非线性失真SI的消除系统。基于作者以往文献的详细理论分析表明，对于使用非线性自干扰消除器的IBFD，当功率放大器具有一定的失真特性而不是理想的线性化时，误码率会得到改善。然而，目前尚不清楚哪种放大器特性最适合 IBFD 系统。在本研究中，我们从理论上分析了自干扰信号，以阐明 IBFD 系统的最佳放大器特性。从理论分析中获得最佳传递函数的优化问题被表述为带有约束的瑞利商，并且我们引入了数值技术来解决优化问题。通过数值实验，我们表明优化后 SI 消除性能、信号干扰失真加噪声比 (SIDNR) 和放大器的功率效率得到了提高。
Although in-band full-duplex (IBFD) communication can theoretically double the spectral efficiency compared with conventional wireless communication technologies, it cannot be realized without reducing a high-power self-interference (SI) signal. Since the SI signal is affected by nonlinear distortion of radio-frequency (RF) circuits of its own terminal, cancellation systems capable of removing the nonlinear distorted SI have been actively developed. Detailed theoretical analysis based on the authors’ past literature shows that for IBFD using a nonlinear self-interference canceller, the symbol error rate is improved when the power amplifier has certain distortion characteristics rather than being ideally linearized. However, it is not yet known what amplifier characteristics are best for the IBFD system. In this study, we theoretically analyze the self-interference signal to clarify the optimum amplifier characteristics for the IBFD system. An optimization problem to obtain an optimum transfer function from theoretical analysis is formulated as an Rayleigh quotient with constraints, and we introduce a numerical technique to solve the optimization problem. By numerical experiments, we show that the SI cancellation performance, signal-to-interference-distortion-plus-noise ratio (SIDNR), and amplifier’s power efficiency are improved by the optimization.