# Enabling NB-IoT on Unlicensed Spectrum

## TL;DR

This paper proposes a framework for NB-IoT to operate in unlicensed spectrum, introducing enhanced synchronization, broadcasting signals, and a novel frequency hopping pattern to ensure robust detection and regulatory compliance.

## Contribution

It introduces a new framework for NB-IoT in unlicensed spectrum with enhanced signals and a frequency hopping pattern, addressing regulatory and coverage challenges.

## Key findings

- Enhanced synchronization and broadcasting signals improve detection robustness.
- A novel frequency hopping pattern generator complies with regulations.
- Performance evaluation shows effective operation in unlicensed bands.

## Abstract

The deployment of Internet of Things (IoT) technologies in unlicensed spectrum is a candidate feature for 5G to support massive connections of IoT devices. Current IoT unlicensed band technologies, such as Sigfox and LoRa, are all at an early stage of deployment without a significant market share. In this context, the MulteFire (MF) Alliance has envisioned to adapt the cellular NB-IoT design to operate within the Sub-1 GHz unlicensed spectrum. However, the diverse regulatory requirements within this unlicensed band put a hurdle to the world-wide deployment of unlicensed band IoT technologies. To settle this challenge, MF has designed a specific framework for narrow-band (NB)-IoT systems operating on unlicensed spectrum (NB-IoT-U), which can be utilized under both the Federal Communications Commission (FCC) and European Telecommunication Standards Institute (ETSI) regulatory requirements. In this paper, enhanced synchronization and physical broadcasting signals are proposed based upon the framework designed by MF with the aim to allow a more robust detection, and to fulfil the coverage targets set for this technology. Furthermore, in order to allow the system to operate as a frequency hopping spread spectrum (FHSS) system, a novel frequency hopping pattern generator compliant with the regulatory requirements is designed, and its performance is evaluated.