MIMO Self-Interference Cancellation

When you push MIMO transmitters into sub-band-full-duplex operation (XDD) or deploy hybrid arrays at scale, “self-interference” shows up in two coupled forms: the BS’s own DL signal leaking into its UL receiver, and the PA nonlinearity generating intermodulation across the array. Equalizer-based digital cancellation handles both — the same architecture pattern, applied at different layers of the stack.

This is a body of work I led or co-authored at Samsung from 2022 onward, documented across journal/conference papers and a series of patents. It is the technical underpinning that makes XDD work in the field and that supports Upper Mid-Band (FR3) Massive MIMO linearity.

Selected publications

• Global Equalizer Self-Interference Cancelation for Hybrid MIMO Systems — U.S. Patent (2023). Global (vs. per-antenna) equalizer SIC architecture for hybrid MIMO.
• Equalizer Digital Self-Interference Cancelation for MIMO Transmitters — U.S. Patent (2022). The original equalizer DSIC formulation for MIMO TX.
• Equalizer Digital Self-Interference Cancelation for Hybrid MIMO Transmitters — U.S. Patent Application (2023). The hybrid-MIMO extension of the 2022 patent.
• Hybrid GMP/Equalizer Digital Self-Interference Cancelation for MIMO Transmitters — U.S. Patent (2022). Hybrid GMP + equalizer architecture combining classical memory-polynomial DPD with equalizer-based SIC.
• Equalizer Assisted Polynomial Based Linearity Enhancement and Self-Interference Canceler — U.S. Patent Application (2022). Polynomial linearity enhancement paired with the equalizer canceler.
• Reducing FDD MMU Form Factor With Active Cancellation — IEEE IMS 2022. Conference paper showing the form-factor savings active cancellation gets you in an FDD MMU.