Backscatter-NOMA: A Symbiotic System of Cellular and Internet-of-Things Networks

TLDR

Non‑orthogonal multiple access (NOMA) is a key technology for enhancing 5G spectrum efficiency, while ambient backscatter communication offers high spectrum and power efficiency for IoT. The paper proposes a backscatter‑NOMA system that integrates a downlink NOMA network with a backscatter device to create a symbiotic cellular‑IoT network. The system operates by having the base station send NOMA‑encoded signals to two cellular users while a backscatter device relays its data over those signals to one user, and the authors analyze outage probabilities, ergodic rates, diversity orders, and slopes for both backscatter‑NOMA and symbiotic radio configurations. When the base station serves only the cellular user decoding backscatter information, the system reduces to a symbiotic radio configuration, and numerical results confirm the theoretical analysis while illustrating the interrelationship between cellular and IoT networks.

Abstract

Non-orthogonal multiple access (NOMA) is envisioned as a key technology to enhance the spectrum efficiency for 5G cellular networks. Meanwhile, ambient backscatter communication is a promising solution to the Internet of Things (IoT), due to its high spectrum efficiency and power efficiency. In this paper, we are interested in a symbiotic system of cellular and IoT networks and propose a backscatter-NOMA system, which incorporates a downlink NOMA system with a backscatter device (BD). In the proposed system, the base station (BS) transmits information to two cellular users according to the NOMA protocol, while a BD transmits its information over the BS signals to one cellular user using the passive radio technology. In particular, if the BS only serves the cellular user that decodes BD information, the backscatter-NOMA system turns into a symbiotic radio (SR) system. We derive the expressions of the outage probabilities and the ergodic rates and analyze the corresponding diversity orders and slopes for both backscatter-NOMA and SR systems. Finally, we provide the numerical results to verify the theoretical analysis and demonstrate the interrelationship between the cellular networks and the IoT networks.