Integrated Self-Adaptive and Power-Scalable Wideband Interference Cancellation for Full-Duplex MIMO Wireless

Yuhe Cao, Jin Zhou

Research output: Contribution to journalArticlepeer-review


A wideband analog/RF interference cancellation technique that is able to autonomously adapt itself to time-varying interference channels and to scale its dc power based on the number of multiple-input-multiple-output (MIMO) array elements is presented. Least-mean square (LMS) adaptive circuitry is co-designed with and partially embedded in a wideband RF/analog interference canceller and a gain-boosted mixer-first receiver (RX), significantly reducing the system complexity and dc power while achieving rapid (microsecond-scale) adaptation. In addition, the proposed canceller is able to digitally adjust its transconductance and coupling strength at the RX side, essentially trading its dc power with the element-level RX noise figure (NF). At the array level, the NF can be lowered by averaging uncorrelated noise across elements. A prototype 0.5-to-2.5-GHz full-duplex (FD) MIMO RX is designed and fabricated using a 65-nm CMOS process. With the adaptive circuitry fully integrated and consuming 14 mW, the cancellers adapt themselves to an unknown channel in 1 \mu \text{s} , providing >20-dB RF/analog interference cancellation across 20-MHz bandwidth (BW) with antenna voltage-standing-wave ratio (VSWR) up to 2:1. Simultaneous self- and cross-interference cancellation in our FD MIMO RX is also demonstrated using the integrated adaptation circuitry, achieving 24-dB overall interference cancellation across 20-MHz BW. The FD MIMO RX with self- and cross-interference cancellation is power-scalable - the NF-power scalability of the FD RX enables a nearly constant canceller dc power per element, despite a quadratic increase of cancellers.

Original languageEnglish (US)
Article number9138449
Pages (from-to)2984-2996
Number of pages13
JournalIEEE Journal of Solid-State Circuits
Issue number11
StatePublished - Nov 2020
Externally publishedYes


  • Adaptive filter
  • CMOS
  • beamforming
  • full duplex (FD)
  • interference cancellation
  • least-mean squares (LMSs)
  • multiple-input-multiple-output (MIMO)
  • self-interference (SI)

ASJC Scopus subject areas

  • Electrical and Electronic Engineering


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