communication_technologies_Internet of things topic

Communication Technologies for IoT
Dr. Bibhas Ghoshal
IIIT Allahabad

Connectivity Considerations
2
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Connectivity between IoT devices and outside world
dictates network architecture
Choice of communication technology dictates IoT device
hardware requirement and costs
Due to presence of numerous applications of IoT
enabled devices, a single networking paradigm not
sufficient to all needs of the consumer or IoT device
Complexity of networks - interference among devices,
network management, heterogeneity in networks,
protocol standardization within networks
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Network Configuration in IoT
Things
Cheruvu S., Kumar A., Smith N., Wheeler D.M. (2020) Connectivity Technologies for IoT.In:Demystifying Internet of Things Security. Apress, Berkeley, CA. https://doi.org/10.1007/978-1-4842-
2896-8_5
3

Some Network Terminologies
4
LAN : Local short range communication, may or may not
connect to Internet
WAN : Connection of various network segments,
connects to internet
Node : connects to other nodes via LAN, maybe
connected to other nodes via WAN directly
Gateway : A router connecting LAN to WAN and Internet,
can implement several LAN and WAN, forwards packets
between LAN and WAN
Proxy : Performs active application layer functions
between nodes and other entities

Functionality Based IoT Protocol
To be Discussed
6
Connectivity – 6LowPAN
Identification - IPv6, URI
Communication / Transport - Wifi, Bluetooth, LPWAN
Data Protocols - MQTT, CoAP, AMQP, Web-socket
Discovery - Physical Web
Semantic – WebThing Model

IEEE 802.15.4
● IEEE 802.15.4 specifies Physical and Media Access Control for low rate
wireless personal area network (LR-WPANs)
● It is maintained by IEEE 802.15 working group
● It is the basis for Zigbee, WirelessHART protocols which extend the
standard by developing upper layers not defined in IEEE 802.15.4
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IEEE 802.15.4 Features
8
● Allows low cost, low speed ubiquitous computing
● Low data rate Wireless Personal Area Network
● Power consumption is minimized due to infrequently occurring
very short packet transmission with low duty cycle
● Highly tolerant of noise and interference and offers link reliability
● Uses carrier sense multiple access with collision avoidance
(CSMA-CA) for channel access
● Multiplexing allows multiple users or nodes interference free
access to same channel at different times
● Transmission for most cases is Line of Sight
● Best case transmission range achieved outdoors is 1000m
● Networking topologies defined : Star and Mesh

IEEE 802.15 Features – Physical Layer
9
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The physical layer provides the data transmission service.
It also, provides an interface to the physical layer
management entity, which offers access to every physical
layer management function and maintains a database of
information on related personal area networks.
The PHY manages the physical radio transceiver, performs
channel selection along with energy and signal management
functions.
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IEEE 802.15 Features – Media Access Layer
10
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The medium access control (MAC) enables the transmission
of MAC frames through the use of the physical channel.
It offers a management interface and itself manages access
to the physical channel and network beaconing.
It also controls frame validation, guarantees time slots and
handles node associations.
Facilitates secure services.
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IEEE 802.15.4 Variants
11
A/B - base version
maximum data rates - 868/915 MHz bands, four physical layers Three
of them preserve the DSSS approach - 868/915 MHz bands; one uses
PSSS
C – China; 779–787 MHz bands
D – Japan ; 950–956 MHz band
E – Industrial Applications
MAC amendment to the existing standard 802.15.4 adopting channel
hopping to improve industrial markets
F – Active RFID users
G - Smart utility networks

ZigBee
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● The ZigBee protocol uses the 802.15.4 standard and
operates in two bands : 868/915MHz and 2.4 GHz
Data rate of 868/915 band : 20/40 Kb/s
Data rate of 2.4GHz band : 250 Kb/s.
The maximum number of nodes in the network is 1024 with a range up to 200
meter.
ZigBee can use 128 bitAES encryption.
end devices can go to sleep mode which saves battery consumption
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Zigbee Network
●A Zigbee network is made up of a Coordinator (C) , router (R) and End Device (E) that are
the IoT devices connected to the network.
●
C – need to be installed first ; it starts a new PAN (Personal Area Network), once started
other zigbee components PAN; selects channel and PAN id
● Router needs to join the network then it can allow other R & E to join the PAN
●Zigbee 3. 0 : enables different application areas to communicate and form a homogenous
network
●Supports connectivity with IP networks such as LAN and WAN, products from different
manufacturers can communicate asa single networking devices
14

Infrastructure based IoT Protocols : IPv6
Internet protocol that provides identification and location system of devices and routes traffic
across the internet
IPv6 is used to deal with problem of IPv4 address exhaustion ( protocols are not interoperable)
IPv6 uses a 128-bit address, theoretically allowing 2128, or approximately 3.4×1038 addresses
IPv6 address are represented as eight groups of four hex digits
Ex : 2001:0db8:0000:0000:0000:8a2e:0370:7334
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Infrastructure based IoT Protocols : 6LoWPAN
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● Supports IPv6 packets over IEEE 802.15.4 WPANs.
● Low power design included - Good for battery-operated IoT devices.
● Supports applications that need wireless internet connectivity at lower data
rates for devices with very limited form factor.
● Example usage : automation and entertainment applications in home,
office and factory environments
● Challenges : management of addresses for devices that communicate
across the two dissimilar domains of IPv6 and IEEE 802.15.4 is
cumbersome
● IEEE 802.15.4 devices are intentionally constrained in form factor to reduce
costs (allowing for large-scale network of many devices), reduce power
consumption (allowing battery powered devices) and allow flexibility of
installation (e.g. small devices for body-worn networks). On the other hand,
wired nodes in the IP domain are not constrained in this way; they can be
larger and make use of mains power supplies.

Communication/ Transport based IoT Protocols
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Communication based IoT Protocols : WiFi
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● Wi-Fi is a Wireless Local Area Network (WLAN) technology based on the IEEE
802.11 standards.
●Wi-Fi Devices - Smartphones, Smart Devices, Laptop Computers, PC, etc.
Applications Areas - Home, School, Computer Laboratory, Office Building
●Wi-Fi devices and Access Points (APs) have a wireless communication range of
about 30 meters indoors.
● Wi-Fi data rate is based on its protocol type :
IEEE 802.11a can achieve up to 54 Mbps IEEE
802.11b can achieve up to 11 Mbps IEEE 802.11g
can achieve up to 54 Mbps IEEE 802.11n can
achieve up to 150 Mbps
IEEE 802.11ac can achieve up to 866.7 Mbps
IEEE 802.11ad can achieve up to 7 Gbps

Communication based IoT Protocols : Bluetooth
19
●
network technology connects mobile devices wirelessly
over a short-range to form a personal area network (PAN).
The Bluetooth architecture has its own independent
model with a stack of protocols, instead of following the
standard OSI model or TCP/IP model.
Bluetooth works in the 2.4 GHz ISM band and uses
frequency hopping. With a data rate up to 3 Mbps and
maximum range of 100m.
Each application type which can use Bluetooth has its
own profile.
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Communication based IoT protocols : Bluetooth
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Communication based IoT protocols : Bluetooth
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Physical Layer :
Radio : defines frequency band, modulation techniques
Baseband : addressing scheme, packet format, timing, power control
Data Link Layer :
Link Manager Protocol(LMP) : establishes logical link between bluetooth devices,
authentication, message encryption
Logical Link Control and Adaptation Layer : adaption between upper layer frame and baseband
layer frame format
Middleware Layer :
RFComm : provides a serial interface with WAP.
Adopted : protocols adopted from standard models (PPP, UDP, TCP)
Service Discovery : takes care of service-related queries like device information so as to
establish a connection between contending Bluetooth devices.
AT command set
Application Layer :
includes the application profiles that allow the user to interact with the Bluetooth applications

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