Optimal tuning of analog self-interference cancellers for full-duplex wireless communication


Self-interference is the primary obstacle to full-duplex wireless communication on a single frequency band. This paper presents a novel convex reformulation for tuning the attenuation and phase shift parameters of a multiple-tap analog self-interference canceller. The standard optimization formulation for a multiple-tap analog canceller is non-convex, causing gradient descent algorithms to converge to local optima. By exploiting the architecture of an ideal analog canceller, an analytical solution for the global optimum is derived that minimizes mean-square error between the canceller and negative channel frequency responses. Multiple taps are necessary to emulate practical antenna coupling channels over a broad bandwidth. Simulated and measured results are presented that achieve significant wideband cancellation in multipath channel environments.

DOI: 10.1109/Allerton.2012.6483225
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