Date Added: Mar 2012
An alternating optimization algorithm was recently proposed for the K-user Multiple-Input Multiple-Output (MIMO) interference channel. For flat-fading channels and feasible problems, this algorithm successfully aligns the interfering signals exploiting the spatial dimensions. In this paper, the authors consider the case in which all pair-wise MIMO channels are frequency-selective (convolutive), and the users transmit broadband signals using a single-carrier scheme. Unlike the flat-fading case, for frequency-selective channels it is necessary to add a spectral mask in the frequency response of the pre-coders and decoders to avoid trivial solutions. They show in the paper that each step of the alternating minimization algorithm can be reformulated as a convex optimization problem in which the autocorrelation function of the pre-coders or decoders is obtained.