IP and LPWAN Convergence

🔤 Acronyms? See the Glossary

Low-Power Wide-Area Network (LPWAN) is the emerging radio technology for the Internet of Things. However, today only 1 to 10% of devices use LPWAN, mainly because LPWAN does not follow the Internet model based on IP protocols, but also because of heavy constraints.

LPWAN networks bring together connectivity technologies adapted to the Internet of Things allowing:

• Very long range communication (up to 40 km)
• Very low energy consumption on the side of the connected object
• High energy efficiency on the network side

To achieve these features, a compromise is made on the bit rates and the supported packet size. In addition, the transmission modalities have limitations to save battery.

Each LPWAN uses its own protocol to cover its particularities and thereby cannot carry IPv6, although this protocol was originally designed to assign addresses to the billions of devices connected to the IoT.

Constrained Networks

Actually, operating on unlicensed ISM (Industrial, Scientific and Medical) radio bands, like Sigfox and LoRaWAN protocols do, implies numerous technical constraints (varying from country to country) and in particular respect for:

• The duty cycle, i.e. the fraction of time during which the device is operated and busy;
• The time on air (ToA), i.e. the fraction of time before the signal is received;
• The Spreading Factor, i.e. the number of bits that can be encoded by a symbol;
• The device classes (A, B, or C) and their consequences on power consumption.

The primary purpose of LPWAN networks like Sigfox and LoRaWAN is to send messages from the sensor to the network: this is the uplink (although downlinks are possible, they are limited by design).

• Sigfox protocol consists of sending 3 successive messages at a power limited to the capacity of the object (maximum 25mW, or 14dBm), with a ToA limitting the messages to 6 per hour. The useful content is limited to 12 bytes for uplinks.
• LoRaWAN protocol has a greater size of useful content (56 bytes) for uplinks. The uplink airtime is limited to 30 seconds per day (24 hours) per node.

The use of cellular networks (e.g. LTE-M or NB-IoT) is suitable for objects needing to communicate more data than the 12 or 56 bytes offered by Sigfox and LoRaWAN respectively. It also allows two-way communications.

The accumulation of all these constraints (both technical and regional) means that these radio band solutions are not interoperable and are difficult to integrate into existing architectures and information systems.

Acklio's IP Tunneling

Acklio innovates by creating an IP tunnel to enable end-to-end communication between devices on LPWAN side and applications IP side. Each device becomes an IP address and is therefore plugged to the same Internet as their destination application. Data can thus cross all the layers of the IP stack, from physical to application layer, transported by a continuous uplink (and downlink as well).

SCHC adaptation layer implemented by Acklio's software enables the IP stack on constrained IoT networks making networks interoperable and unified in a same global network, while:

• Improving energy efficiency and network load by reducing the volume of data exchanged;
• Adapting compression and fragmentation to regional parameters and radio conditions dynamically;
• Keeping message headers and payload inside the LoRaWAN capabilities to save the downlink;
• Saving bandwidth by preventing continuous synchronization while keeping communication context.