Secure Relay Beamforming over Cognitive Radio Channels

TL;DR

This paper addresses secure relay beamforming in cognitive radio channels, optimizing performance while ensuring secrecy and minimal interference, using quasiconvex optimization and sub-optimal null space schemes.

Contribution

It introduces a quasiconvex optimization framework for secure relay beamforming with power constraints and proposes efficient null space beamforming schemes.

Findings

Optimal beamforming solutions under power constraints

Proposed null space schemes reduce computational complexity

Enhanced secrecy and interference management in cognitive radio

Abstract

In this paper, a cognitive relay channel is considered, and amplify-and-forward (AF) relay beamforming designs in the presence of an eavesdropper and a primary user are studied. Our objective is to optimize the performance of the cognitive relay beamforming system while limiting the interference in the direction of the primary receiver and keeping the transmitted signal secret from the eavesdropper. We show that under both total and individual power constraints, the problem becomes a quasiconvex optimization problem which can be solved by interior point methods. We also propose two sub-optimal null space beamforming schemes which are obtained in a more computationally efficient way.