MULTIUSER DOWNLINK BEAMFORMING WITH INTERFERENCE CANCELLATION USING A SDP-BASED BRANCH-AND-BOUND ALGORITHM

We consider in this paper multiuser downlink beamforming with interference cancellation (BFIC). In our BFIC problem, the total transmitted power of the base station (BS) is minimized under signalto- interference-plus-noise ratio (SINR) requirements of the mobile stations (MSs) and single-stage interference cancellation (SSIC) is adopted at the MSs. The challenge of the problem lies in its combinatorial and non-convex nature. We propose a semidefinite programming (SDP) based branch-and-bound (BnB) algorithm to (optimally) solve the BFIC problem. The SDP-based BnB algorithm employs SDP and sequential second-order cone programming. We further develop a fast heuristic algorithm for large-scale applications. Simulations show that employing SSIC achieves significant reductions in total transmitted BS power. The proposed SDP-based BnB algorithm optimally solves all considered instances of the BFIC problem, and the heuristic algorithm yields near-optimal solutions.