In-Band Full-Duplex Interference for Underwater Acoustic Communication Systems

This work presents an adaptive self-interference cancellation (SIC) method for in-band full-duplex underwater acoustic (IBFD-UWA) systems along with a model for the self-interference (SI) for shallow-water acoustic channels. The proposed system utilizes orthogonal frequency division multiplexing with quadrature phase shift keying modulation to exchange information between two nodes operating in IBFD mode. The proposed adaptive SIC scheme employs the normalized least-mean-square (NLMS) algorithm to suppress the SI signal and avoid saturating the local analog-to-digital (ADC) converter. Unlike existing research works, we investigate the effect of imperfect detection of the signal of interest on the ability of the SIC to diminish the SI signal. We provide experimental results to support the SI model developed and simulation results to demonstrate the ability of the proposed adaptive SIC scheme to mitigate the SI signal to approximately the level of the ambient noise.