Secure Beamforming in MISO NOMA Backscatter Device Aided Symbiotic Radio Networks

TL;DR

This paper proposes a secure beamforming algorithm for a MISO NOMA backscatter device aided symbiotic radio network, enhancing secrecy rates against eavesdroppers in low-power IoT communications.

Contribution

It introduces a novel algorithm based on constrained convex optimization to maximize secrecy rates in SR networks with backscatter devices.

Findings

Achieves larger secrecy rate region than OMA networks.

Demonstrates effectiveness of the proposed beamforming algorithm.

Enhances security in low-power IoT symbiotic radio systems.

Abstract

Symbiotic radio (SR) networks are possible solutions to the future low-power wireless communications for massive Internet of Things devices. In this paper, we investigate a multiple-input-single-output non-orthogonal multiple access (NOMA) backscatter device (BD) aided SR network with a potential eavesdropper. In the network, a base station (BS) broadcasts signals to a central user and a cell-edge user using the NOMA protocol. With ambient backscatter modulation, the BD transmits its own messages to the central user over incident signals from the BS. We propose a constrained concave convex procedure-based algorithm which maximizes the $\epsilon$-outage secrecy rate from the BD to the central user under the achievable secrecy rate constraints from the BS to the central and cell-edge users. Simulation results illustrate that our proposed network achieves a much larger secrecy rate region than the orthogonal multiple access (OMA) network.