一种同频全双工非线性自干扰消除方法

An Algorithm for Nonlinear Self-Interference Cancellation in Full-Duplex System

同频全双工系统可以在相同时间和相同频率上接收和发送信息,相比传统的双工方式,理论上可以实现频谱利用率的倍增。有效自干扰消除是实现同频全双工通信的关键,目前已有的自干扰消除方法包括:天线隔离、模拟消除和数字消除。但是,大多数消除方法都忽略了同频全双工节点中放大器非线性失真的影响,导致整体自干扰消除性能受限。因此,提出了一种针对接收端放大器非线性失真的数字自干扰消除方法,该方法将自干扰信道和非线性放大器描述为Wiener模型,通过对模型参数的估计,重构出自干扰信号,并在基带实现数字自干扰消除。仿真结果表明,该方法可以有效的消除线性自干扰信号及非线性失真,与不存在非线性失真的情况相比,消除性能相差少于1 d B。

Transmitting and receiving simultaneously at the same frequency band, full-duplex system can double the spectrum efficiency of the current duplex system. Some techniques, mainly including antenna self-interference suppression, analog self-interference suppression and digital self-interference suppression, are used to suppress self-interference signals and realize full-duplex communication. However, most of the existing self-interference cancellation schemes ignore the nonlinearity effect of the low noise ampli- fier （LNA） at the receiver chain, and this would limit the amount of cancellable self-interference power. In this paper, a novel digital nonlinear interference cancellation technique is proposed to mitigate the non- linear self-interference induced by LNA. The technique models the self-interference channel and the non- linear LNA with a Wiener nonlinearity, and then by appropriate estimation of model parameter, the known transmit data is processed and cancelled at digital baseband. Simulation results indicate that the proposed technique could achieve a performance that is less than ldB off from the performance of a linear full-duplex system.