Secure Layered Transmission in Multicast Systems with Wireless Information and Power Transfer

TL;DR

This paper develops a power allocation algorithm for secure multicast wireless systems that simultaneously provides energy transfer and confidentiality, optimizing power use while satisfying diverse QoS and energy harvesting needs.

Contribution

It introduces a novel optimization framework using SDR for secure layered multicast transmission with energy harvesting, including suboptimal schemes and optimality conditions.

Findings

Significant power savings over isotropic energy signals.

Effective secure communication with energy harvesting constraints.

Proposed schemes outperform existing methods in simulations.

Abstract

This paper considers downlink multicast transmit beamforming for secure layered transmission systems with wireless simultaneous information and power transfer. We study the power allocation algorithm design for minimizing the total transmit power in the presence of passive eavesdroppers and energy harvesting receivers. The algorithm design is formulated as a non-convex optimization problem. Our problem formulation promotes the dual use of energy signals in providing secure communication and facilitating efficient energy transfer. Besides, we take into account a minimum required power for energy harvesting at the idle receivers and heterogeneous quality of service (QoS) requirements for the multicast video receivers. In light of the intractability of the problem, we reformulate the considered problem by replacing a non-convex probabilistic constraint with a convex deterministic constraint. Then, a semidefinite programming relaxation (SDR) approach is adopted to obtain an upper solution for the reformulated problem. Subsequently, sufficient conditions for the global optimal solution of the reformulated problem are revealed. Furthermore, we propose two suboptimal power allocation schemes based on the upper bound solution. Simulation results demonstrate the excellent performance and significant transmit power savings achieved by the proposed schemes compared to isotropic energy signal generation.