Confidential communication in downlink beamforming

Abstract

This paper deals with the problem of secure transmission in downlinkbeamforming. In this scenario, a base station, which usually serves information to an amount of users, wants to transmit a confidential message to one of the users. Focusing on the beamforming solution, we derive all possible weighted solutions. With this, each non-intended receiver has an im- portance factor and, therefore, the resulting beamformer is able to properly reconfigure its secure transmission varying the weighting factors. This deri vation is done via multicrite- ria optimization, which allows us to transform a quasiconvex problem into a semidefinite one and, thus, reduce the compu- tational complexity. Numerical results show the performance of the method.