Intercell Interference Management For Downlink Beamforming With Imperfect CSI

In this paper, we consider an optimum multicell downlink beamforming that minimizes the worst-case of the resulting overall interference induced on the other users of the adjacent cells in the presence of imperfect channel state information (CSI). Users on the cell edge mostly suffer from severe interference, which result in low data rate. The aim is to ensure that the data rate at the cell edge users for any given transmit power remains above the required level. We consider a spherical uncertainty set to model the imperfection in CSI between the true and the estimated channel coefficients. The original non-convex problem is formulated as the second-order cone programming (SOCP) and then recast the convex constraints into a tractable formulation in linear matrix inequality (LMI) form. Finally, we evaluate the effectiveness and efficiency of the proposed SOCP robust method with different values of the error radii and compared against the conventional and non-robust approach through numerical simulations.