IPv6 over Low Power Wide Area Networks: The IoT is currently developing in several dimensions. As the number of connected IoT devices grows steadily, the number of communications technologies for IoT devices increases, too.
Well-established IoT technologies, such as IEEE 802.15.4 and Bluetooth Low Energy (BLE), are characterized by a rather short communication range, generally in the order of tens or a few hundreds of meters.
However, with such a reduced range, a considerable amount of infrastructure (e.g. relay nodes and/or gateways) is needed to ensure connectivity of IoT devices over a large area (e.g. a city).
This approach requires a potentially complex networking solution and leads to high network deployment, maintenance and management cost.
In order to overcome the aforementioned issues, the category of wireless communication technologies called Low Power Wide Area Networks (LPWANs) has emerged.
LPWAN technologies define star topology networks whereby a single base station covers up to hundreds of thousands of IoT devices with a multiyear IoT device battery lifetime, while supporting a multikilometer link range.
These characteristics are achieved at the expense of extremely low data rates and small payloads, which are sufficient to many common industrial IoT applications.
In fact, LPWANs have quickly attracted the interest of industry, academia and standards development organizations, with 4 billion LPWAN devices predicted by 20251.
Flagship LPWAN technologies include LoRaWAN, Sigfox and Narrowband IoT (NB-IoT).
Furthermore, the IEEE 802.15.4w task group has been recently chartered to optimize IEEE 802.15.4 for LPWAN scenarios.
To fully exploit the potential of LPWANs, Internet connectivity support is required. Therefore, LPWAN devices need to be able to run IP.
In particular, IP version 6 (IPv6) is assumed, since it offers a massive address space and self-configuration tools.
However, IPv6 was designed for resource-rich networking environments (e.g. Ethernet), whereas typical IoT network scenarios offer significantly constrained energy, computation, and communication capabilities.
For over one decade, the IETF IPv6 over Low-power Wireless Personal Area Networks (6LoWPAN) Working Group (WG) and the IETF IPv6 over Networks of Resource-constrained Nodes (6Lo) WG have developed adaptation layers to enable and optimize IPv6 over a wide range of IoT linklayer technologies, hereafter called 6LoWPAN/6Lo technologies.
These include IEEE 802.15.4, BLE, ITU-T G.9959 (Z-Wave), Digital Enhanced Cordless Telecommunications – Ultra Low Energy (DECT-ULE) and Near Field Communication (NFC), among others.
Nevertheless, 6LoWPAN/6Lo adaptation style would incur unaffordable overhead over LPWANs, given the extremely restricted communication resources of LPWAN technologies.
For example, the sustained capacity of 6LoWPAN/6Lo technologies is of at least a few kbit/s, while some LPWAN technologies are limited to as low as the mbit/s (i.e. millibit/s!) order. read full pdf here
