BackCom Assisted Hybrid NOMA Uplink Transmission for Ambient IoT

TL;DR

This paper introduces a novel BackCom-assisted H-NOMA uplink scheme for energy-constrained ambient IoT devices, providing analytical insights, resource allocation algorithms, and demonstrating performance improvements over traditional OMA.

Contribution

It develops a new BackCom-assisted H-NOMA uplink scheme for ambient IoT, along with resource allocation algorithms and analytical results distinguishing it from conventional H-NOMA.

Findings

BackCom-assisted H-NOMA outperforms OMA in simulations.

Two algorithms effectively balance system performance and complexity.

Analytical results validate the scheme's advantages.

Abstract

Hybrid non-orthogonal multiple access (H-NOMA) has recently received significant attention as a general framework of multiple access, where both conventional orthogonal multiple access (OMA) and pure NOMA are its special cases. This paper focuses on the application of H-NOMA to ambient Internet of Things (IoT) with energy-constrained devices, where a new backscatter communication (BackCom) assisted H-NOMA uplink scheme is developed. Resource allocation for H-NOMA uplink transmission is also considered, where an overall power minimization problem is formulated. Insightful understandings for the key features of BackCom assisted H-NOMA and its difference from conventional H-NOMA are illustrated by developing analytical results for the two-user special case. For the general multi-user scenario, two algorithms, one based on the branch-bound (BB) principle and the other based on successive convex approximation (SCA), are developed to realize different tradeoffs between the system performance and complexity. The numerical results are also provided to verify the accuracy of the developed analytical results and demonstrate the performance gain of H-NOMA over OMA.