Iterative Nonlinear Self-Interference Cancellation for In-Band Full-Duplex Wireless Communications Under Mixer Imbalance and Amplifier Nonlinearity

Abstract

This paper presents an iterative estimation and cancellation technique for nonlinear in-band full-duplex transceivers with IQ imbalances and amplifier nonlinearities. The estimation process of the proposed scheme consists of three stages, namely, the channel response estimation, IQ imbalance estimation, and power amplifier and low-noise amplifier (LNA) nonlinearities estimation. For the estimation of the parameters and improvement of the accuracy, distortions are compensated by cancellation or inversion with the latest estimated parameters. On the one hand, the channel response is estimated on the time domain; on the other hand, the IQ imbalance and nonlinearities are estimated on the frequency domain for a more straightforward estimation and superior accuracy. In the cancellation process of the proposed scheme, the received signal is compensated with the estimated parameters of the LNA and receiver IQ imbalance before cancellation because the desired signal is received with a high-power self-interference and is distorted by the radiofrequency receiver impairments. Simulation results show that the proposed technique can achieve higher cancellation performance compared with the Hammerstein canceller when the LNA is saturated by the self-interference. Additionally, the performance of the proposed canceller converges much faster than that of the Hammerstein canceller.

Theoretical Analysis of In-Band Full-Duplex Radios With Parallel Hammerstein Self-Interference Cancellers

“…5, we can also see that the cancellation performance is significantly degraded by saturation of the LNA when ρ 2 11 > −55 dB even if P = 7. The parallel Hammerstein canceller cannot estimate and regenerate the nonlinear self-interference caused by the LNA; to achieve higher performance, we need to consider the nonlinearity of the LNA [19], [33]- [39].…”

“…cancellation has been achieved using TX/RX isolation [7]- [10], analog domain cancellation [11]- [13], and digital domain cancellation [14]- [19]. Digital cancellation is the final step in a series of cancellation processes.…”

RF Impairments in Wireless Transceivers: Phase Noise, CFO, and IQ Imbalance – A Survey

“…Finally, an ML detector is developed by applying a whitening filer, eigenvalue decomposition, and singular value decomposition beamforming. References [536], [537] investigate SI cancellation in OFDM full-duplex systems with frequency-flat IQ imbalance and a non-linear power amplifier. In [536], a pilot-aided iterative algorithm for estimating the channel, IQ imbalance, and power amplifier and low-noise amplifier non-linearities is proposed.…”

Self-Interference Channel Training for Full-Duplex Massive MIMO Systems

“…Therefore, to make the FD technique feasible, extensive studies have been conducted on SI cancellation (SIC) schemes. In general, both analog-domain SIC [ 18 , 19 , 20 , 21 , 22 , 23 ] and digital-domain SIC [ 24 , 25 , 26 , 27 , 28 ] are required. Regarding analog SIC schemes, radio frequency (RF) and baseband (BB) tapping approaches were studied in [ 18 , 19 ], respectively.…”

“…In [ 27 ], a digital SIC scheme based on an independent component analysis was proposed. In [ 28 ], an iterative nonlinear method was studied for FD systems under mixer imbalance and amplifier nonlinearity.…”