Resource Allocation for Secure Communication in Systems with Wireless Information and Power Transfer

TL;DR

This paper develops resource allocation algorithms for secure multiuser MISO systems with simultaneous wireless information and power transfer, optimizing power use while ensuring security and energy harvesting needs.

Contribution

It introduces a semidefinite programming relaxation approach and two suboptimal schemes for secure communication and energy harvesting in wireless systems.

Findings

Proposed schemes achieve near-optimal performance.

Significant power savings through artificial noise optimization.

Effective balance between security and energy harvesting demonstrated.

Abstract

This paper considers secure communication in a multiuser multiple-input single-output (MISO) downlink system with simultaneous wireless information and power transfer. We study the design of resource allocation algorithms minimizing the total transmit power for the case when the receivers are able to harvest energy from the radio frequency. In particular, the algorithm design is formulated as a non-convex optimization problem which takes into account artificial noise generation to combat potential eavesdroppers, a minimum required signal-to-interference-plus-noise ratio (SINR) at the desired receiver, maximum tolerable SINRs at the potential eavesdroppers, and a minimum required power delivered to the receivers. We adopt a semidefinite programming (SDP) relaxation approach to obtain an upper bound solution for the considered problem. The tightness of the upper bound is revealed by examining a sufficient condition for the global optimal solution. Inspired by the sufficient condition, we propose two suboptimal resource allocation schemes enhancing secure communication and facilitating efficient energy harvesting. Simulation results demonstrate a close-to-optimal performance achieved by the proposed suboptimal schemes and significant transmit power savings by optimization of the artificial noise generation.