Full duplex (FD) communication has the potential to double the throughput of wireless links while occupying the same bandwidth of half duplex communication. To enable FD communication, the self-interference (S1) signal is to be suppressed down to the noise floor. S1 cancellation can be achieved via antenna suppression, active analog cancellation, and digital cancellation. At high transmit power levels, the nonlinear behavior of the transceiver hardware degrades linear S1 channel estimation; hence, S1 cancellation results in reduced total suppression. In this article, we review nonlinear DSIC solutions in the literature, and we present a comprehensive integrated linear and nonlinear digital S1 cancellation framework with nested and residual approaches, where nonlinear algorithms, memory polynomial, support vector regression, and orthonormalized least mean squares algorithms are implemented together with linear cancellation. The performance of the proposed integrated framework is evaluated in comparison with well-known nonlinear digital cancellation techniques by implementing all techniques on the same software defined FD radio setup, consisting only of a single antenna and a WARP v3 board. It is shown that the integrated residual approach can enhance the total S1 suppression performance significantly by up to 7 dB as compared to linear-only digital S1 cancellation and by up to 4 dB with respect to existing nonlinear-only techniques observed at moderate power levels, and the integrated nested approach can provide an improvement of up to 6 dB over linear-only and 3 dB over nonlinear-on-ly digital S1 cancellation for high power settings. All schemes are also evaluated in terms of training overhead and computational complexity, providing insights about the trade-off between cost and performance at different power levels.

中文翻译：

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用于全双工通信的集成线性和非线性数字对消

全双工（FD）通信有潜力使无线链路的吞吐量增加一倍，同时占用半双工通信的相同带宽。为了实现FD通信，必须将自干扰（S1）信号抑制到本底噪声。可以通过天线抑制，主动模拟消除和数字消除来实现S1消除。在高发射功率电平下，收发器硬件的非线性行为会降低线性S1信道估计；因此，S1抵消导致总抑制降低。在本文中，我们回顾了文献中的非线性DSIC解决方案，并提出了一种采用嵌套和残差方法的全面集成的线性和非线性数字S1抵消框架，其中非线性算法，存储多项式，支持向量回归，和正交归一化的最小均方算法与线性抵消一起实现。通过在相同的软件定义的FD无线电设置中实施所有技术，与仅由单个天线和WARP v3板组成的所有技术相比较，与所提出的非线性数字消除技术进行了比较，从而评估了所提出的集成框架的性能。结果表明，与仅线性数字S1消除相比，集成残差方法可以显着提高总S1抑制性能达7 dB，相对于在中等功率水平下观察到的现有仅非线性技术而言，集成残差方法可提高高达4 dB，对于高功率设置，集成的嵌套方法可以使纯线性S1消除比纯线性提高6 dB，比纯非线性数字S1消除3 dB。