CSF117 Module 9 Low Power Wide Area Network
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Date
2023-04-23
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Abstract
Welcome to the Low Power Wide Area Networks (LPWANs). This module aims to facilitate learning of the various interconnecting one master with multiple slaves wirelessly for purposes of sending and receiving data.
Description
Welcome to the Low Power Wide Area Networks (LPWANs) module. In this module we will answer questions such as What is LPWAN? How do LPWANs work? What are the benefits of LPWANs? What are LPWANs used for?. We will create an end to end IoT Wide Area Network consisting of several nodes, or what is known as a wireless sensor network. Each note will be able to transmit to any node. We will create a web of devices using the LoRaWAN module to achieve low power wide area connectivity.
IoT devices tend to usually be battery powered. It is therefore preferable to have communication devices that will consume as little power as possible so as to remain active for longer periods of time. Low Power Wide Area Network (LPWANs) help IoTs achieve just that. As the name suggests, they consume low power and keep the IoTs connected. LPWANs use unlicensed frequencies to transmit data.
It is predicted that the number and variety of IoT devices will greatly grow in the near future. These devices will need means of communication to send data from sensors to processing nodes so as to allow the users and stakeholders better understand the environment under review.
Common types of LPWAN are LoRaWAN, NB-IoT, Sigfox and Weightless. LoRaWAN is very scalable, supports bidirectional communication and is low cost. NB-IoT operates over cellular networks and therefore is more secure and can achieve better data rates. Sigfox uses ultra-narrow band modulation and therefore can cover distances of 30 kilometers. Weightless uses Wideband Frequency Modulation and Orthogonal Frequency to achieve long distance and low power connectivity.
LPWANs can be used in any scenario where Internet of Things devices are distributed over a large geographical area. This can include smart parking, smart street lighting, soil monitoring in agriculture and so on.
Transmission range and power consumption are the two main factors in LPWAN networks that are considered for scalable applications such as in agriculture where not so much data is transmitted. To address these two issues one approach proposed is to use the ultra narrowband technique that tends to focus signal in a narrowband and therefore enhance signal-to-noise (SNR) ratio. An example of this is the Narrowband-IoT (NB-IoT).
The other approach is to combat high noise power in a wideband receiver by utilizing coding gain. An example of this is the LongRange (LoRa) technique that increases transmission range with enhanced power efficiency.
LPWAN examples include LoRa, NB-IoT, Long Term Evolution (LTE) Machine Type Communications (LTE-MTC/LTE-M) and Bluetooth low energy (BLE). LTE-M has a higher data rate than the other LPWANs but works over the licensed spectrum. It is able to transmit video due to the high data rate and give end-to-end security.
NB-IoT also operates over the licensed spectrum like GSM and LTE. It has higher data rate than LoRa. Depending on conditions, it can transmit up to 250 Kbps uplink and 170 kbps downlink. In terms of security, NB-IoT offers end-to-end security just like LTE.
LoRa is a physical communication layer. Unlike LTE-M and NB-IoT, it works over an unlicensed spectrum of Sub-GHz bands 433 MHz, 868 MHz and 915 MHz. It is more resilient regarding burst noise than NB-IoT because LoRa channels span over a wider bandwidth. LoRaWAN is the most common MAC-layer of LoRa. LoRaWAN is an open standard and allows IoT devices to communicate independently and asynchronously.