Kim, Yonghwi;
Wong, Kai-Kit;
Zhang, Jianzhong;
Chae, Chan-Byoung;
(2025)
Low Complexity Frequency Domain Nonlinear Self-Interference Cancellation for Flexible Duplex.
IEEE Transactions on Wireless Communications
10.1109/TWC.2025.3554988.
(In press).
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Abstract
Nonlinear self-interference (SI) cancellation is essential for mitigating the impact of transmitter-side nonlinearity on overall SI cancellation performance in flexible duplex systems, including in-band full-duplex (IBFD) and sub-band full-duplex (SBFD). Digital SI cancellation (SIC) must address the nonlinearity in the power amplifier (PA) and the in-phase/quadrature-phase (IQ) imbalance from up/down converters at the base station (BS), in addition to analog SIC. In environments with rich signal reflection paths, however, the required number of delayed taps for time-domain nonlinear SI cancellation increases exponentially with the number of multipaths, leading to excessive complexity. This paper introduces a novel, low-complexity, frequency domain nonlinear SIC, suitable for flexible duplex systems with multiple-input and multiple-output (MIMO) configurations. The key approach involves decomposing nonlinear SI into a nonlinear basis and categorizing them based on their effectiveness across any flexible duplex setting. The proposed algorithm is founded on our analytical results of intermodulation distortion (IMD) in the frequency domain and utilizes a specialized pilot sequence. This algorithm is directly applicable to orthogonal frequency division multiplexing (OFDM) multi-carrier systems and offers lower complexity than conventional digital SIC methods. Additionally, we assess the impact of the proposed SIC on flexible duplex systems through system-level simulation (SLS) using 3D ray-tracing and proof-of-concept (PoC) measurement.
| Type: | Article |
|---|---|
| Title: | Low Complexity Frequency Domain Nonlinear Self-Interference Cancellation for Flexible Duplex |
| Open access status: | An open access version is available from UCL Discovery |
| DOI: | 10.1109/TWC.2025.3554988 |
| Publisher version: | https://doi.org/10.1109/TWC.2025.3554988 |
| Language: | English |
| Additional information: | This version is the author accepted manuscript. For information on re-use, please refer to the publisher’s terms and conditions. |
| Keywords: | Full-duplex (FD), flexible duplex, and selfinterference cancellation (SIC) |
| UCL classification: | UCL UCL > Provost and Vice Provost Offices > UCL BEAMS UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Engineering Science > Dept of Electronic and Electrical Eng |
| URI: | https://discovery.ucl.ac.uk/id/eprint/10207414 |
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