# Minimizing The Age of Information: NOMA or OMA?

## TL;DR

This paper compares NOMA and OMA in 5G networks for minimizing the average Age of Information, revealing that higher spectral efficiency in NOMA does not always lead to lower AoI.

## Contribution

It introduces a stochastic hybrid systems framework to analytically compare the AoI performance of NOMA and OMA in 5G MTC networks.

## Key findings

- NOMA can have higher spectral efficiency than OMA.
- Higher spectral efficiency does not guarantee lower AoI.
- NOMA does not always outperform OMA in AoI minimization.

## Abstract

In this paper, we examine the potentials of Non- Orthogonal Multiple Access (NOMA), currently rivaling Orthogonal Multiple Access (OMA) in 3rd Generation Partnership Project (3GPP) standardization for future 5G networks Machine Type Communications (MTC), in the framework of minimizing the average Age of Information (AoI). By leveraging the notion of Stochastic Hybrid Systems (SHS), we find the total average AoI of the network in simple NOMA and conventional OMA environments. Armed with this, we provide a comparison between the two schemes in terms of average AoI. Interestingly, it will be shown that even when NOMA achieves better spectral efficiency in comparison to OMA, this does not necessarily translates into a lower average AoI in the network.