Embedded sensors are enabling a wide range of emerging smart services in domains ranging from healthcare to smart homes and cities. They are waiting to be connected to the internet and rapidly becoming crucial components of a valuable Internet of Things (IoT). The variety of wireless sensor system applications demands appropriate wireless connectivity. Several new technologies and standards are popping up, fit for short or large range, and various data rate requirements. Dedicated networks are being deployed for Machine Type Communication. This tutorial will bring a theoretical and practical initiation of wireless technologies tailored for connecting embedded sensors. It will explain fundamental concepts of wireless propagation, highlighting the challenges and opportunities to realize low power connections. Several actual technologies and standards for different categories of connections will be introduced. A few illustrative use cases will be presented. A hands-on session will allow the participants to experiment with EFM32 Happy Gecko developer boards, cooperating in small teams. In a final session, a glance at future trends will be given. The tutorial will be concluded with an overview of interesting relevant resources and a discussion with the participants on the expectations for follow up beyond the tutorial.

1. Connecting sensors
with low power wireless technologies
IEEE SENSORS 2017
October 29, 2017- Glasgow, Scotland
dramco.be/tutorials/low-power-lora/

2. We welcome you!
2
Liesbet Van der Perre Geoffrey OttoyGilles Callebaut
dramco.be/tutorials/low-power-lora
Guus Leenders

4. Power Critically Low
E2330_tt_54

6. The planned schedule for this tutorial
6
Introduction – start the installation
Low power wireless technologies
IoT gateway
Coffee break
IoT devices: design challenges
Hands-on
Future outlook - wrap up

7. 1 2 3
The Things, which
are embedded with
sensors and/or
actuators
The network
that connects
them
The systems that
process data
to/from the Things
source: https://www.linkedin.com/pulse/internet-things-iot-dummies-rajat-kochhar

8. Connecting sensors: Variety of applications in diverse
sectors!
© Qualcomm

9. 9
A wonderful uncontrollable mysterious world
Wireless communication
and propagation basics

11. ‘Our’ Tiagnose Watch
TI contest winner, KULeuven DraMCo lab realization

13. Sensors on bridges communicate to update their health
batteries eventually drain out

14. Set-up of a (wireless) communication system
Source:
message
Transmitter Channel Receiver Destination

15. Build-up of a wireless system
transmitter
transmit antenna
Receiver
Receive antenna
Put info on the wave
Detect info
The real ‘magic’

16. It’s a wonderful mysterious world
Nor cost nor constraints of wires:
✓ installation cost 
✓ mobility 
✓ flexibility 
✓ robustness (mechanical) 
yet: conquer ‘the air’
– difficult, un-controllable
– open medium, spectrum = shared

17. Bits travel fast and need energy to travel (far)

18. Radio-propagation in free space
in far field of antenna
Pr = Pt .Gr.Gt.(/ 4. .d)2
Received power Pr
o  transmit power Pt
o  gain transmit antenna Gt
o  gain receive antenna Gr
o  distance d
The far field:
o Region far from the antenna,
o Where radiation pattern does not change shape with distance.
o Dominated by radiated fields, E- and H-fields orthogonal to each other and the
direction of propagation as with plane waves.

19. Wireless channels: fading!
Large-and small-scale fading
r(t) = h(t).s(t)
= m(t).r0(t)
© SKLAR

20. Large scale fading:
Mean path loss
Lp(d)(dB) ~10n log (d/d0)
Typical: n> 2
Note n can be < 2:
guided wave phenomenon
© SKLAR

21. Connecting things to the Internet:
networks can be classified upon covered area
source: http://thesedays.com/thoughts/understanding-connectivity-for-internet-of-things
Personal
Local
Neighborhood
Wide
Area Network

22. Low Power Wide Area
source: https://nl.linkedin.com/in/roxan-van-empel-6678583b

23. Selecting an appropriate connectivity solution:
what matters? Technical functional specifications
• Range: home – local area – wide area?
• Data rate – up and/or downlink
• Mobility
• Latency (~response time): maybe crucial for safety-critical control operations
• Interference:
o Has become non-negligible: number of wirelessly connected devices large
and expected to grow steadily over the next years!
o Especially in unlicensed bands and in open environments
o Feature = difficult to predict and control
• Reliability: %’s or 0.000x%’s?

24. Selecting an appropriate connectivity solution:
what matters? Technical non- functional specs
• Power options vs. autonomy requirements:
o Grid power or battery?
o Chargeable (e.g. outdoor solar cell – basement - …)?
o How accessible (for battery replacement)?
• Integration and environmental aspects:
o Size/weight
o Outdoor/indoor – humidity – radiation - …
o Design - esthetics?

25. Selecting an appropriate connectivity solution:
Non-Technical considerations
• Costs involved:
o Devices
o Development
o License?
• HW/SW solutions availability (maybe from different vendors)
• Maturity
• Standard compliance – interoperability - roaming
• Expertise - support available?

26. ‘Personal’ (few m’s)– area:
bluetooth - flavors

27. Local area sensing & control: Zigbee at help
ZigBee: operates on the IEEE 802.15.4 physical radio specification
Operates in unlicensed bands: 2.4 GHz, 900 MHz and 868 MHz
Supports mesh networking

28. 28
Wi-Fi for the IoT
802.11 ah/af

29. Local area solutions:
‘Common’ WiFi and new flavors: technologies

30. ‘Common’ WiFi and new flavors: the application view

31. IEEE802.11ah promoted as MTC solution
‘HaLow will enable a variety of new power-efficient use cases in
the Smart Home, connected car, and digital healthcare, as well
as industrial, retail, agriculture, and Smart City environments.’

32. IEEE802.11ah: a solution for M2M
to be deployed world-wide?
© Microwaves & RF

33. LPWAN
33
Distance (m)
Rate (kbps)
10 000
100
1
10 1000100
x10
x10
WPAN
Wi-Fi for the IoT
IEEE 802.11ah HaLow
• Favourable propagation
• MAC enhancements

34. 34
Broadcast TV channels Broadcast TV channels
Other Wireless
Uses
e.g., 3G, Wi-Fi
Potential TV White Spaces (TVWS)
~ time and location
User allocation

35. 35
Broadcast TV channels Broadcast TV channels
Other Wireless
Uses
e.g., 3G, Wi-Fi
Potential TVWS
~ time and location
User allocation
470 – 710 MHz
White-Fi / Super Wi-Fi

36. LPWAN
36
Distance (m)
Rate (kbps)
10 000
100
1
10 1000100
x10
x10
WPAN
Wi-Fi for the IoT
IEEE 802.11ah HaLow
IEEE 802.11af White-Fi

37. Attempt to simplify the scene for personal – local area
© Greenpeak – now Qorvo

38. LPWAN Technologies
Gilles Callebaut
gilles.callebaut@kuleuven.be
KU Leuven campus Ghent,
Belgium
IEEE Sensors 2017
October 29, 2017- Glasgow, UK

39. What distinguishes LPWAN
from other technologies?

40. Cost
Data Rate
Energy
Coverage
Topology
Mostly unlicensed spectrum
(ISM bands)
Low chip and subscription
cost
Lower frequency bands
(i.e. sub-GHz)
Simple coding
→ low data rate, low cost, low
power
Reduce radio on time
Device induced communication,
sleep, low data
Predominantly single hop star-of-stars topology
Easy deployment → low installation and maintenance
cost

41. 41
http://waviot.com/wp-content/uploads/2016/02/img-lpwan-3g-zeegbii-comparison-917x650.png

42. t
42
LPWAN Landscape
https://i.imgur.com/0jQKy6b.jpg

43. 43
IEEE 802.11ah HaLow
IEEE 802.11af White-Fi
Distance (m)
Rate (kbps)
10 000
100
SIGFOX
LoRaWA
N
Weightless-P
DASH7
1
100 1000
And others

44. 44
Global IoT Provider
SIGFOX

45. SIGFOX
45
SIGFOX
Cloud
SIGFOX
modem
Certification
uplink classes
Classes 0 – 4
IT
Services
UNB IP
HTTP,
MQTT, …
Global IoT Provider
SIGFOX Network
Operator

46. SIGFOX
Radio Technology – UL (EU)
46
UNB DBPSK
@ 100bps 140 msg/day
Payload 12 bytes
Frame 24 bytes
https://www.ismac-nc.net/wp/wp-content/uploads/2017/08/sigfoxtechnicaloverviewjuly2017-170802084218.pdf

47. 47
Very lean, yet scalable
SIGFOX

48. SIGFOX
Radio Technology – UL (EU)
48
R-FDMA
Time Diversity
Frequency Diversity
Space DiversityUNB
https://www.disk91.com/2017/technology/internet-of-things-technology/learn-
about-sigfox-and-lora-radio-technologies/
https://www.ismac-nc.net/wp/wp-content/uploads/2017/08/sigfoxtechnicaloverviewjuly2017-
170802084218.pdf

49. SIGFOX
Radio Technology – DL (EU)
49
https://www.ismac-nc.net/wp/wp-content/uploads/2017/08/sigfoxtechnicaloverviewjuly2017-
170802084218.pdf

50. SIGFOX
Radio Technology – DL (EU)
50
GFSK @ 600bps 4 msg/day/device
Payload 8 bytes
600 Hz
δ
https://www.ismac-nc.net/wp/wp-content/uploads/2017/08/sigfoxtechnicaloverviewjuly2017-
170802084218.pdf

51. SIGFOX
Radio Technology – Object Initiated Communication (EU)
51
500~525ms
𝑓1 𝑓2 𝑓3

52. SIGFOX
Radio Technology – Object Initiated Communication (EU)
52
500~525ms
Downlink
Message
20s
25s
𝑓1 𝑓2 𝑓3
𝑓1 + δ

53. SIGFOX
Radio Technology – Object Initiated Communication (EU)
53
500~525ms
Downlink
Message
OOB
20s
25s
𝑓1 𝑓2 𝑓3
𝑓1 + δ

54. SIGFOX
Coverage
54
Currently present in
over 30 countries, they
aim to cover 100% of
the globe within the
next few years.
https://www.sigfox.com/en/coverage

55. 55
They provide LoRa-enabled Communication
Let’s you deploy IoT networks
LoRaWAN

56. LoRa & LoRaWAN
56
= PHY
Radio modulation patented by Semtech
Based on Chirp Spread Spectrum (CSS)
= MAC + System Architecture
LoRa LoRaWAN
http://www.nanotron.com/assets/img/technology/Upchirp-downchirp.gif

57. 57
A Robust Modulation Technique
LoRa

58. 58
BW
Preamble Sync Symbols
LoRa Signal
Detection
Time sync.
Detect starting of payload
Payload
125, 250, 500 Hz
http://www.sghoslya.com

59. 59
BW
http://www.sghoslya.com

60. 60
http://www.sghoslya.com

61. 61
Adapts to its surroundings
LoRaWAN

62. LoRaWAN
Adaptive Data Rate
62
7
8
…
12
SF / Bitrate
Energy /
Time on Air

63. 63
Device Classes
LoRaWAN

64. LoRaWAN Class A
Device Classes
64
Downlink
Message𝑓3
Rx
Window
1
Rx delay 1
Rx delay 2
Detect Preamble
Preamble
Detected

65. LoRaWAN
Device Classes
65
Battery Lifetime
Downlink Network
Communication Latency
A

66. LoRaWAN Class B
Device Classes
66
Rx
Window
2
𝑓3
Rx
Window
1
Rx delay 1
Rx delay 2
Detect Preamble

67. LoRaWAN Class B
Device Classes
67
Rx
Window
2
Rx
Window
Scheduled receive
window

68. LoRaWAN
Device Classes
68
Battery Lifetime
Downlink Network
Communication Latency
A
B

69. LoRaWAN Class C
Device Classes
69
𝑓3Rx Window Rx Window

70. LoRaWAN
Device Classes
70
Battery Lifetime
Downlink Network
Communication Latency
A
B
C

71. 71
Deploy your own network!
LoRaWAN

72. LoRaWAN
Deployment Strategies
72
Private
Networks
Commercial
Networks
Crowdsourced
Networks

73. 73
Crowdsourced Networks gain traction
LoRaWAN

74. 74
https://www.thethingsnetwork.org/map

75. 75
What about cellular?

76. Low Power Wide Area Networks (LPWAN) –
3GPP (members) propose ‘central RAN’
3rd Generation Partnership Project: Global initiative for broadband mobile,
succeeded in globally harmonizing cellular standards.
Vision: one central all-encompassing Radio Access Network (RAN) (for
technical & commercial reasons)
http://www.3gpp.org
https://www.youtube.com/watch?v=2nsEAw_SirQ

77. 3GPP-LTE is considering
different UE (User Equipment) categories
target

78. Mobile standards for IoT?
• GPRS
• EDGE
• WCDMA/HSPA
• LTE Category 4
• LTE Category 1
• LTE Category 0
• LTE-M (or Release 13)
• Extended Coverage GSM (EC-GSM)
• Narrowband IoT (NB-IoT)
• 5G IoT

79. 3GPP-LTE not longer only about higher speed

80. Incorporating NB-IoT in cellular networks:
‘just a SW upgrade’?

81. What’s expected in the next releases?
5G in preparation - New Radio (NR) label

82. M2M use cases: the 3GPP-LTE perspective

83. The license vs unlicensed perspective
http://mobile-experts-blog.blogspot.be/2016/02/a-reheated-alphabet-soup-for-iot.html

84. The range vs. bandwidth perspective

85. The view of the mobile blog-spotter
• Mobile standards: will certainly have a place in the market because of the high quality of
GSM and LTE links, and the huge global network of infrastructure that can be used.
• Still missing in cellular landscape: low-data, low-cost tier of the market, where most of the
big applications are today.
• LPWA vs. LTE? multiple answers:
o Having an LTE lineup of Porsches, Ferraris, and Lamborghinis will only appeal to a
small audience.
o The world needs a few sports cars, some pickup trucks, fleets of cheap sedans, and
countless bicycles.

86. 86
Which Low Power Wireless
Technology to choose and use?

87. 87
Application DataDevice
• Coverage?
• Local / National /
Global
• Indoor / Outdoor
• Time to market?
• Expected lifetime?
• Size?
• Updates? (OTA)
• Fixed or Mobile?
• Data size?
• Periodicity?
• UL / DL focused?

88. IoT Selector Tool
88
dramco.be/tools/iot-selector/

89. 89

90. IoT Gateways
Gilles Callebaut
gilles.callebaut@kuleuven.be
KU Leuven campus Ghent,
Belgium
IEEE Sensors 2017
October 29, 2017- Glasgow, UK

91. Overview
INTERNET OF
THINGS

92. INTERNET OF
THINGS
Sensors /
actuators
Communication Cloud
Infrastructure

93. Functionality of an IoT Gateway
93
Protocol translation Data aggregation Access control and
managing of local IoT nodes
Edge computing
and analytics
End user application Different Connectivity
Protocols

94. Software Stack
94
OS / RTOS
Application Runtime
Data Managements & Messaging
Network Management
Field Protocols IoT Protocols
Run
application
code
UDP
TCP
LoRaWAN
BLE
MQTT
ZigBee
Configure
Start
Shutdown
Connectivity
RemoteManagement

95. Gateway Architectures
95
From centralised IoT to a distributed internet of things.
Roman, R., Zhou, J., & Lopez, J. (2013). On the features and challenges of security and privacy in distributed internet of things. Computer Networks, 57(10), 2266-2279.

96. Gateway Architectures
96
Roman, R., Zhou, J., & Lopez, J. (2013). On the features and challenges of security and privacy in distributed internet of things. Computer Networks, 57(10), 2266-2279.
From centralised IoT to a distributed internet of things.

97. Gateway Architectures
97
Roman, R., Zhou, J., & Lopez, J. (2013). On the features and challenges of security and privacy in distributed internet of things. Computer Networks, 57(10), 2266-2279.
From centralised IoT to a distributed internet of things.

98. Gateway Architectures – Intranet of Things
98
Roman, R., Zhou, J., & Lopez, J. (2013). On the features and challenges of security and privacy in distributed internet of things. Computer Networks, 57(10), 2266-2279.

99. Gateway Architectures – Collaborative IoT
99
Roman, R., Zhou, J., & Lopez, J. (2013). On the features and challenges of security and privacy in distributed internet of things. Computer Networks, 57(10), 2266-2279.

100. Gateway Architectures
100
From centralised IoT to C-IoT and Intranet of Things
to distributed internet of things.
Roman, R., Zhou, J., & Lopez, J. (2013). On the features and challenges of security and privacy in distributed internet of things. Computer Networks, 57(10), 2266-2279.

101. Gateway Architectures – Distributed IoT
101
Roman, R., Zhou, J., & Lopez, J. (2013). On the features and challenges of security and privacy in distributed internet of things. Computer Networks, 57(10), 2266-2279.

102. 102
How to deploy our
networks?
http://case.schollaart.net/img/deploy.jpg

103. Deployment Strategies
103
Private
Networks
Public Networks Crowdsourced
Networks

104. Architecture of an IoT device
Bart Thoen
Bart.thoen@kuleuven.be
KU Leuven campus Ghent,
Belgium
IEEE Sensors 2017
October 29, 2017- Glasgow, UK

105. INTERNET OF
THINGS
Sensors /
actuators
Communication Cloud
Infrastructure

106. IoT device (noun) (pl. IoT devices) A tiny computing device that collects
data and transmits data to the internet.
(Wireless)
communication
Microprocessor Sensors
Sensors /
actuators
Communication Cloud
Infrastructure

107. Anatomy of an IoT node
Microprocessor with
signal processing
Sensor with interfacing
electronics
Wireless transceiver
Battery and power
design Image source: twitter.com/acrobotic/status/759263763220561920

108. Architecture of an IoT node
Real world
Sensors with
interfacing
electronics
Microprocessor
with signal
processing
(Wireless)
transceiver

109. Connectivity Massive data
processing
Real time data
Design challenges
Sensing platformSmall form factor
Low power design

110. Design challenges
Small form factor
﹣Embedded in physical systems
﹣Keep design features, design and
functionality
﹣Low impact on surroundings (e.g.,
wearables in medicine)
Image source: instructables.com/id/Apple-II-Watch/; goo.gl/oJHLV5

111. Sensing platform
Design challenges
﹣Monitor surroundings
﹣Fusion analog sensing system and
microprocessor
Low power design

112. Real time data
Design challenges
– Send all data immediately?
– Use max. packet length of connectivity
Low power design
Connectivity
Massive data processing

113. Connectivity
Design challenges
﹣Ideal: high BW
﹣Connection between devices and cloud
﹣A range of possibilities
Low power design
Image source: goo.gl/Prt6E1

114. Connectivity
Design challenges
﹣Ideal: high BW
﹣Connection between devices and cloud
﹣A range of possibilities
Low power design

115. Massive data
processing
Design challenges
﹣Huge amounts of data
﹣First stage of processing on node
﹣Efficient processing algorithms
Low power design
Connectivity
Image source: goo.gl/H24Rmk

116. Low power design
Design challenges
﹣No reliable power supply
﹣Small batteries
﹣Energy harvesting
Connectivity
Massive data processing
Real time data
Sensing platform
Image source: goo.gl/MT9RtW

117. v
Low power design
Design challenges
1995 2000 2005 2010 2015
Evolution of cell phone features and battery capacity
Features Battery capacity
image source: goo.gl/Kqtvs6 image source: goo.gl/PrMPZv

118. Low power design
Design challenges
• All design steps require low power
• How-to low power
﹣ Use low power / energy engine
﹣ Use efficiently
﹣ Use sleep modes
• Energy consumption drains battery and heats
system
• Possible energy harvesting? (solar, motion,…)

119. Architecture of an IoT node
Real world
Sensors with
interfacing
electronics
Microprocessor
with signal
processing
(Wireless)
transceiver

120. D R A M C O
EFM32 Wonder Gecko
LoRA Extension board
Architecture of the presented IoT device
Limited
battery
Microprocessor Wireless
tranceiver
Multiple sensors

121. D R A M C O
EFM32 Wonder Gecko
LoRA Extension board
Limited
battery
Microprocessor Wireless
tranceiver
Sensors with interfacing electronics
Variety of sensors (temperature, humidity, light,…)
Low power
﹣Use of low power systems
﹣Use of deep sleep (or turn off)
﹣Interrupt usage (no polling)
Only collect data if threshold is met

122. D R A M C O
EFM32 Wonder Gecko
LoRA Extension board
Limited
battery
Microprocessor Wireless
tranceiver
Microprocessor with signal processing
Implement thresholds before processing
Accumulate high-latency data before sending
Low Power
﹣Low power ARM architecture
﹣Processor deep sleep
﹣Use HW encryption
﹣Reduce clock frequency

123. D R A M C O
EFM32 Wonder Gecko
LoRA Extension board
Limited
battery
Microprocessor Wireless
tranceiver
Wireless transceiver
Use of a low bandwidth protocol: LoRa
Low Power
﹣Low overhead data
﹣Use modem deep sleep

124. Coffee break

125. Hands-on
Liesbet Van der Perre
Gilles Callebaut
Guus Leenders
KU Leuven campus Ghent,
Belgium
IEEE Sensors 2017
October 29, 2017- Glasgow, UK

126. Overview
dramco.be/tutorials/low-power-lora/ieee-sensors

127. Overview
dramco.be/tutorials/low-power-lora
dramco.be/tutorials/low-power-lora

128. 128
TT
LoRa
ateway
LoRa node
ashboard
IP

129. 129
TT
LoRa
ateway
LoRa node
ashboard
IP
Store Sensor Data in the Cloud

130. 130
TT
LoRa
ateway
LoRa node
ashboard
IP
Store Sensor Data in the Cloud
Register application

131. 131
TT
LoRa
ateway
LoRa node
ashboard
IP
Going Low Power

132. Overview
IoT Development Environment
Getting the development environment ready
Store Sensor Data in the Cloud
Transform data into valuable information
IoT Dashboard
Display information on dashboard
Going Low Power
Reduce power consumption

133. Overview
IoT Development Environment
Getting the development environment ready
Store Sensor Data in the Cloud
Transform data into valuable information
IoT Dashboard
Display information on dashboard
Going Low Power
Reduce power consumption
– Cloud environment
– IoT node environment

134. Overview
IoT Development Environment
Getting the development environment ready
Store Sensor Data in the Cloud
Transform data into valuable information
IoT Dashboard
Display information on dashboard
Going Low Power
Reduce power consumption

135. Overview
Firmware
Hardware

136. Overview
IoT Development Environment
Getting the development environment ready
Store Sensor Data in the Cloud
Transform data into valuable information
IoT Dashboard
Display information on dashboard
Going Low Power
Reduce power consumption

137. Overview
IoT Development Environment
Getting the development environment ready
Store Sensor Data in the Cloud
Transform data into valuable information
IoT Dashboard
Display information on dashboard
Going Low Power
Reduce power consumption
– Accumulate Sensor Data
– Hardware vs Software Encryption
– Low Power Tweet

138. We welcome you!
138
Liesbet Van der Perre Geoffrey OttoyGilles Callebaut
dramco.be/tutorials/low-power-lora
Guus Leenders

139. Connecting sensors
with low power wireless technologies
IEEE Sensors 2017
October 29, 2017- Glasgow, UK
dramco.be/tutorials/low-power-lora/