Reliable Communication using LoRaWAN for Industrial IoT devices
Typ
Examensarbete för masterexamen
Program
Publicerad
2021
Författare
Blom Rydell, Joar
Otterlind, Oliver
Modellbyggare
Tidskriftstitel
ISSN
Volymtitel
Utgivare
Sammanfattning
The Internet of Things (IoT) area is growing by the minute, with more and more devices
being connected to the internet. Long Range Wide Area Network (LoRaWAN)
is one technology that makes this possible. It is made to deliver long-range coverage
while at the same time using low power. However, with the increasing demand
for low latency requirements on connected devices, the same requirements must be
fulfilled for the network technology. In particular, the Industrial Internet of Things
(IIoT) devices requires the network link to be of low latency and high reliability.
This thesis aims to evaluate LoRaWAN in terms of reliability. This evaluation
will be done by comparing the default reliability method against an alternative
method. In order to evaluate reliability, latency, Packet Delivery Rate (PDR) and
Packet Acknowledgment Rate (PAR) are important metrics to see how reliable the
communication is. Furthermore, having concrete values on these metrics will help
companies determine whether LoRaWAN is suitable for IIoT devices.
The proposed alternative reliability method is one found in the literature. It alters
the uplink and downlink windows of LoRaWAN by introducing a redundant
retransmission scheme. This scheme utilizes the Time-on-Air (ToA) of the previous
transmission for retransmissions instead of a static value LoRaWAN uses in the default
protocol. It further adds a redundant retransmission step if the previous one
failed. This thesis shows that the alternative reliability method provides a significant
reduction in latency by 69%, an increase in PDR by 1.1% but at the cost of a
slightly lower PAR by 3%. Lower PAR is an indication of more network traffic and
power usage.
This thesis concludes that there are pros and cons to both methods. The default
method is better suited for dense networks with fewer requirements on latency and
higher requirements on battery power. In contrast, the alternative method is better
suited for less dense networks and higher latency requirements. These trade-offs are
ones the manufacturers need to consider when analyzing whether or not LoRaWAN
is suitable, that is, both in terms of the manufacturers’ environment requirements
but also the IIoT device requirements.
Beskrivning
Ämne/nyckelord
Azure , Cloud , Gateway , IoT , IIoT , Latency , LoRa , LoRaWAN , LPWAN , Reliability