Full-duplex (FD) wireless can significantly enhance spectrum efficiency but requires effective self-interference (SI) cancellers. RF SI cancellation (SIC) via frequency-domain equalization (FDE), where bandpass filters channelize the SI, is suited for integrated circuits (ICs). In this paper, we explore the limits and higher layer challenges associated with using such cancellers. We evaluate the performance of a custom FDE-based canceller using two testbeds; one with mobile FD radios and the other with upgraded, static FD radios in the PAWR COSMOS testbed. The latter is a lasting artifact for the research community, alongside a dataset containing baseband waveforms captured on the COSMOS FD radios, facilitating FD-related experimentation at the higher networking layers. We evaluate the performance of the FDE-based FD radios in both testbeds, with experiments showing 95 dB overall achieved SIC (52 dB from RF SIC) across 20 MHz bandwidth, and an average link-level FD rate gain of 1.87x. We also conduct experiments in (i) uplink-downlink networks with inter-user interference, and (ii) heterogeneous networks with half-duplex and FD users. The experimental FD gains in the two types of networks depend on the users' SNR values and the number of FD users, and are 1.14x-1.25x and 1.25x-1.73x, respectively, confirming previous analytical results.

翻译：全双工无线通信可显著提升频谱效率，但需要有效的自干扰消除器。基于频域均衡的射频自干扰消除技术，通过带通滤波器对自干扰信号进行信道化处理，适用于集成电路实现。本文探索了此类消除器的性能极限及高层挑战，并利用两个测试平台评估基于频域均衡的自定义消除器性能：一个采用移动全双工无线电，另一个采用PAWR COSMOS测试平台中升级的静态全双工无线电。后者为研究社区提供了持久性实验设施，同时附带在COSMOS全双工无线电上捕获的基带波形数据集，支持高层网络层的全双工相关实验。我们在两个测试平台上对基于频域均衡的全双工无线电进行性能评估，实验表明在20 MHz带宽内可实现95 dB总体自干扰消除（其中射频自干扰消除贡献52 dB），平均链路级全双工速率增益达1.87倍。此外，我们开展了以下两类实验：（i）存在用户间干扰的上行-下行链路网络，（ii）半双工与全双工用户共存的异构网络。实验显示两类网络中的全双工增益取决于用户信噪比值及全双工用户数量，分别为1.14倍至1.25倍和1.25倍至1.73倍，验证了先前的理论分析结果。