In this letter, a self-interference cancellation (SIC) method is presented for short-range full-duplex multiple-input–multiple-output (MIMO) communication. The proposed SIC consists of the following steps. First, each peer has multiple transmitting (Tx) and receiving (Rx) antennas optimally arranged to form a one-rank self-interference (SI) matrix between Tx and Rx. The optimal antenna arrangement is derived using a geometric model. Second, null steering is performed by eigenmode beamforming excluding the primary eigenmode of the SI matrix. This realizes powerful SIC at the cost of processing just a single degree of freedom. The effectiveness of the proposed SIC is evaluated by electromagnetic simulations. The results confirm that it reduces the SI level by 22.76 dB. In addition, it is shown the proposal offers achievable rates 1.50 times those of the half-duplex scheme in line-of-sight (LOS).

中文翻译：

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短程全双工 MIMO 中自干扰消除的最佳天线布置

在这封信中，提出了一种用于短距离全双工多输入多输出 (MIMO) 通信的自干扰消除 (SIC) 方法。拟议的 SIC 包括以下步骤。首先，每个对等点具有多个最佳布置的发射 (Tx) 和接收 (Rx) 天线，以在 Tx 和 Rx 之间形成单秩自干扰 (SI) 矩阵。最佳天线布置是使用几何模型导出的。其次，通过不包括 SI 矩阵的主本征模的本征模波束成形来执行零点控制。这以处理单个自由度为代价实现了强大的 SIC。所提出的 SIC 的有效性是通过电磁模拟来评估的。结果证实，它使 SI 电平降低了 22.76 dB。此外，显示该提案提供了可实现的费率 1。