Narrowband Internet of Things (NB-IoT): From Physical (PHY) and Media Access Control (MAC) Layers Perspectives

TLDR

Narrowband IoT (NB‑IoT) is a 3GPP‑defined LTE‑based cellular technology designed for low‑power, low‑cost, low‑data‑rate massive machine‑type communication in LPWANs, featuring single‑antenna, low‑order modulation PHY layers and a single physical resource block MAC scheduler. This survey aims to comprehensively review NB‑IoT design changes and research developments at the PHY and MAC layers, and to highlight existing and emerging challenges to motivate future work. The survey examines NB‑IoT design changes, EPC modifications for SCEF handling of IP and non‑IP traffic via Control and User Planes, and potential deployment scenarios in future heterogeneous wireless networks.

Abstract

Narrowband internet of things (NB-IoT) is a recent cellular radio access technology based on Long-Term Evolution (LTE) introduced by Third-Generation Partnership Project (3GPP) for Low-Power Wide-Area Networks (LPWAN). The main aim of NB-IoT is to support massive machine-type communication (mMTC) and enable low-power, low-cost, and low-data-rate communication. NB-IoT is based on LTE design with some changes to meet the mMTC requirements. For example, in the physical (PHY) layer only single-antenna and low-order modulations are supported, and in the Medium Access Control (MAC) layers only one physical resource block is allocated for resource scheduling. The aim of this survey is to provide a comprehensive overview of the design changes brought in the NB-IoT standardization along with the detailed research developments from the perspectives of Physical and MAC layers. The survey also includes an overview of Evolved Packet Core (EPC) changes to support the Service Capability Exposure Function (SCEF) to manage both IP and non-IP data packets through Control Plane (CP) and User Plane (UP), the possible deployment scenarios of NB-IoT in future Heterogeneous Wireless Networks (HetNet). Finally, existing and emerging research challenges in this direction are presented to motivate future research activities.