Sampled-data H∞ optimization for self-interference suppression in baseband signal subspaces

In this article, we propose a design method of self-interference cancelers for wireless relay stations taking account of the baseband signal subspace. The problem is first formulated as a sampled-data H_∞ control problem with a generalized sampler and a generalized hold, which can be reduced to a discrete-time ℓ²-induced norm minimization problem. Taking account of the implementation of the generalized sampler and hold, we adopt the filter-sampler structure for the generalized sampler, and the uspampler-filter-hold structure for the generalized hold. Under these implementation constraints, we reformulate the problem as a standard discrete-time H^∞ control problem by using the discrete-time lifting technique. A simulation result is shown to illustrate the effectiveness of the proposed method.