This term ‘LPWAN’ was first coined in 2013 for a wireless technology meant for M2M and
IoT devices. This technology fills the empty gap between mobile (3G, CDMA, and LTE) and
short-range wireless (Wi-Fi and Bluetooth) networks. It was primarily designed for machine
communication instead of human communication. Human communication requires voice,
data, video, and low latency to ensure seamless user experience; but machine communica-
tion, especially for IoT applications and devices require occasional low levels of data transfer
with any mobility. Thus, LPWAN oers better connectivity for the companies to deliver their
services. Many Businesses utilize LPWANs to establish their own secure networks and link
their IoT devices. Example: sensors to monitor the air quality level in an area or water level
in a river.
LPWAN devices usually have a very good battery life as they only need to transmit small
packets of data at random intervals. They can even last for a decade with one or two batteries.
With the help of this technology, sensors can be deployed in buildings or hard to access areas
and left there for a long time to transmit data. LPWAN facilitates a wide area of coverage which
is never limited by proximity to the distance among the access points. This power-saving trans-
lates into lower costs for the end users and companies who are using this technology.
The disadvantage of LPWAN would be the latency. This latency is measured in milliseconds
(ms) for voice and data communications; but machine communication is measured in seconds
(s). However, LPWAN is mainly designed for machine communication instead of human com-
munication.
Discovery Protocols
Physical Web
The main aim of behind the idea of Physical Web is to connect the real world. Physical web
is a technology developed by Google that makes it possible to generate beacon notifications
on mobile devices, without the need for integrating an SDK in an application. It is supported
through Eddystone and it explains the convergence of the physical world and the digital world.
Eddystone beacons and chrome web browser work as the backbone of the physical web.
It is an open approach to make it possible to interact quickly and seamlessly with physical
objects and locations. This is done with devices known as beacons that emit small identifiers
such as short URLs to anyone listening. These beacons are equipped with low energy Bluetooth
(Bluetooth 4.0) protocol. This helps them to operate even running on low battery.
Physical web works as a discovery service in which beacons can scan for nearby devices
and send permission messages to them. Once a device user receives such a message, he/she will
be needed to allow access to the established physical web. If the access gets granted by the user,
a list of all the beacons nearby will be visible on their device. The physical web then will start
broadcasting relevant URLs that are personalized to the user’s location. In short, it allows you
to get a list of URLs getting broadcasted by objects in the environment near you.
mDNS
mDNS or multicast DNS is computer protocol that eectively resolves the name of the hosts to
IP addresses inside small networks that do not contain a local name server. This protocol works
as a zero-configuration service that uses the exact same programming interfaces, operating
schematics, and packet formats as the unicast DNS (Domain Name System). Stuart Cheshire is
known to have designed mDNS as stand-alone protocol. However, it can also work in concert
with normal DNS servers.
114 Internet of Things
Internet_of_Things_CH05_pp105-140.indd 114 9/3/2019 10:13:55 AM
..................Content has been hidden....................
You can't read the all page of ebook, please click here login for view all page.