Coordinated Beamforming for Multiuser MISO Interference Channel under Rate Outage Constraints

摘要

This paper studies the coordinated beamforming design problem for themultiple-input single-output (MISO) interference channel, assuming only channeldistribution information (CDI) at the transmitters. Under a given requirementon the rate outage probability for receivers, we aim to maximize the systemutility (e.g., the weighted sum rate, weighted geometric mean rate, and theweighed harmonic mean rate) subject to the rate outage constraints andindividual power constraints. The outage constraints, however, lead to acomplicated, nonconvex structure for the considered beamforming design problemand make the optimization problem difficult to handle. {Although} thisnonconvex optimization problem can be solved in an exhaustive search manner,this brute-force approach is only feasible when the number oftransmitter-receiver pairs is small. For a system with a large number oftransmitter-receiver pairs, computationally efficient alternatives arenecessary. The focus of this paper is hence on the design of such efficientapproximation methods. In particular, by employing semidefinite relaxation(SDR) and first-order approximation techniques, we propose an efficientsuccessive convex approximation (SCA) algorithm that provides high-qualityapproximate beamforming solutions via solving a sequence of convexapproximation problems. The solution thus obtained is further shown to be astationary point for the SDR of the original outage constrained beamformingdesign problem. {Furthermore}, we propose a distributed SCA algorithm whereeach transmitter optimizes its own beamformer using local CDI and informationobtained from limited message exchange with the other transmitters. Oursimulation results demonstrate that the proposed SCA algorithm and itsdistributed counterpart indeed converge, and near-optimal performance can beachieved for all the considered system utilities.