A Hierarchical Self-Interference Canceller for Full-Duplex LPWAN Applications Achieving 52–70-dB RF Cancellation
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Bibliographic record
Abstract
We present a radio frequency self-interference (SI) canceller chip for low-power wide area network (LPWAN) basestations. To enhance the cancellation capability without necessitating unreasonable resolution, power consumption, and area, we introduce a hierarchical cancellation technique using a nested vector modulator (VM) implementation. Nesting a 7-b and two 6-b stages, a 16-b theoretical and >13-b measured resolution is obtained per tap. LPWAN channels have large group delay and group delay spread in tens of ns, and a requirement for >100 dB of analog SI cancellation. To enable large ON-chip group delay, we leverage frequency translation circuits, and in comparison to prior art, decouple impedance matching requirement from tap delay implementation to realize range/resolution from 16 ns/33 ps to 80 ns/150 ps. We demonstrate 64 dB of RF SI cancellation over 0.8-MHz bandwidth (BW) with a three-tap implementation for an LPWAN wireless channel. For more controlled environments, up to 70-dB cancellation is shown. Each tap occupies 0.21 mm2 of area and consumes 12.3 mA of current with a 1.2-V supply voltage. The whole chip occupies 1.2 mm2 and consumes 44.28 mW of power in a 65-nm CMOS process.
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Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.001 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.001 |
| Science and technology studies | 0.001 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.001 | 0.000 |
| Research integrity | 0.000 | 0.001 |
| Insufficient payload (model declined to judge) | 0.000 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from it