Rapid technological advances in the past made possible the miniaturization of network devices to meet the cost and power consumption requirements in IoT and M2M scenarios. What is missing in this picture is a radio technology with both long range capability and a very low cost footprint. Existing radio technologies such as 3G/4G or Short Range Radio do not aptly meet the requirements of IoT scenarios because they are either too expensive or are not able to provide the required range. Other wireless technologies are geared towards high bandwidth which is in most cases not a requirement for IoT. Emerging LPWAN technologies such as ETSI LTN or LoRAWAN are poised for filling the gap by providing long range (up to 40km) and low power connectivity. These technologies allow low cost radio devices and operation thus enabling scaling up IoT applications.

1. © Peter R. Egli 2015
1/11
Rev. 1.00
LPWAN – Low Power Wide Area Network indigoo.com
Peter R. Egli
INDIGOO.COM
OVERVIEW OF EMERGING TECHNOLOGIES FOR
LOW POWER WIDE AREA NETWORKS IN
INTERNET OF THINGS AND M2M SCENARIOS
LPWANLOW POWER
WIDE AREA NETWORK

2. © Peter R. Egli 2015
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Rev. 1.00
LPWAN – Low Power Wide Area Network indigoo.com
Contents
1. The sweet spot for LPWANs
2. LPWAN requirements and characteristics
3. The need for long range wireless connectivity
4. LPWAN network topology
5. Link budget for LPWAN devices
6. Receiver sensitivity for LPWAN devices
7. Technologies for LPWAN

3. © Peter R. Egli 2015
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1. The sweet spot for LPWANs
Different wireless technologies cover different applications with regard to range and bandwidth.
Long-range applications with low bandwidth requirements that are typical for IoT and M2M
scenarios are not well supported by these existing technologies.
LPWAN technologies are targeted at these emerging applications and markets.
Long RangeShort Range
Low BW
High BW
Medium BW
Medium Range
LPWAN
BlueTooth
BLE
ZigBee /
802.15.4
802.11a
802.11b
802.11g
802.11ac
802.11ad
802.11n
RFID /
NFC
WBAN
802.15.6
2G
3G
4G
5G
VSAT
WPAN
802.15.3
Key:
BW: Bandwitch
IoT: Internet of Things
M2M: Machine to Machine

4. © Peter R. Egli 2015
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2. LPWAN requirements and characteristics (1/2)
The needs of IoT and M2M applications pose some unique requirements on LPWAN
technologies as shown in the comparison with other wireless technologies:
Range
Power
Consumption
Bandwidth
Radio Chipset
Costs
Radio
Subscription Costs
Transmission
Latency
Number of
Base Stations
Geographical
Coverage, Penetration
LPWAN
3G/4G/5G
ZigBee
802.15.4

5. © Peter R. Egli 2015
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2. LPWAN requirements and characteristics (2/2)
Characteristic Target Value for LPWAN Technologies
Long range 5 – 40km in the open field
Ultra low power Battery lifetime of 10 years
Throughput
Depends on the application, but typically a few hundred
bit / s or less
Radio chipset costs $2 or less
Radio subscription costs $1 per device and year
Transmission latency
Not a primary requirement for LPWAN. IoT applications are
typically insensitive to latency.
Required number of base
stations for coverage
Very low. LPWAN base stations are able to serve thousands
of devices.
Geographic coverage,
penetration
Excellent coverage also in remote and rural areas. Good in-
building and in-ground penetration (e.g. for reading power
meters).

6. © Peter R. Egli 2015
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3. The need for long range wireless connectivity
Devices in IoT applications (the “things”) are typically installed in the field on residential
premises, public places like restaurants or cafés or on industrial plant sites.
Using short range radio connectivity complicates the IoT setup due to the implications of
wired on-site connectivity (firewalls, NAT, port and protocol filtering).
Short range radio connectivity for IoT devices:
Direct long range connectivity (LPWAN) for IoT devices:
End Customer Premises
Wired
network
Access Network /
Internet
SRD
Gateway
Cloud, Apps
Cloud A
A
A
Short range radio devices (SRD)
such as ZigBee require using a
gateway for long-range backhaul.
The gateway is typically hooked
up to some on-site wired network
which is not under control of the
IoT provider.
End Customer Premises Access Network /
Internet
Cloud, Apps
Cloud A
A
ABase
Station
Long range connectivity allows
direct access to the devices in
the field.
The base station typically serves
a large number of devices thus
greatly reducing costs.

7. © Peter R. Egli 2015
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4. LPWAN network topology (1/2)
The wireless portion of LPWAN networks uses a star topology.
This obviates the need for complicated wireless mesh routing protocols which would greatly
complicate the implementation of end devices and drive up power consumption.
A. Direct device connectivity (base station):
 A base station provides connectivity to a large number of devices.
 The traffic is backhauled to servers (cloud) through TCP/IP based networks (Internet).
 The base station is responsible for protocol translation from IoT protocols such as MQTT
or CoAP to device application protocols.
LPWAN Connectvitiy Access Network /
Internet
Cloud & Servers
Cloud
Base
Station
Star topology for long
range radio connectivity
Wired backhaul,
TCP/IP based
(e.g. MQTT)
Applications
A
A
A
A

8. © Peter R. Egli 2015
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Short Range Conn.
4. LPWAN network topology (2/2)
B. Indirect device connectivity through a LPWAN gateway:
 In setups where devices cannot be directly reached through LPWAN, a local gateway
bridges LPWAN connectivity to some short range radio (SRD) technology (e.g. ZigBee,
BLE).
 The gateway typically runs on mains power since it serves a larger number of devices
and must convert between LPWAN and SRD radio technologies and protocols.
 Gateways may help to improve security since more powerful security algorithms can be
implemented on the gateway than is possible on the constrained devices.
LPWAN Connectvitiy Access Network /
Internet
Cloud & Servers
Cloud
Base
Station
Star topology for long
range radio connectivity
Wired backhaul,
TCP / IP
(e.g. MQTT)
Applications
A
A
A
A
Gateway
Short range
local connectivity

9. © Peter R. Egli 2015
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SRx
[dBm]
5. Link budget for LPWAN devices
Link budget:
As in most radio systems, the link budget is an important measure for power calculation.
The link budget calculates the power received at the receiver and accounts for gains and losses
along the transmission path.
PTX
[dBm]
+dB
-dB
GTX
[dBi]
LTX
[dB]
0dB
LFS
[dB]
LM
[dB]
GRX
[dBi]
LRX
[dB]
Transmission
Path
𝑷 𝑹𝑿 = 𝑷 𝑻𝑿 + 𝑮 𝑻𝑿 − 𝑳 𝑻𝑿 − 𝑳 𝑭𝑺 − 𝑳 𝑴 + 𝑮 𝑹𝑿 − 𝑳 𝑹𝑿
𝑷 𝑹𝑿 = 𝑹𝒆𝒄𝒆𝒊𝒗𝒆𝒅 𝒑𝒐𝒘𝒆𝒓 𝒅𝑩𝒎
𝑷 𝑻𝑿 = 𝑺𝒆𝒏𝒅𝒆𝒓 𝒐𝒖𝒕𝒑𝒖𝒕 𝒑𝒐𝒘𝒆𝒓 𝒅𝑩𝒎
𝑮 𝑻𝑿 = 𝑺𝒆𝒏𝒅𝒆𝒓 𝒂𝒏𝒕𝒆𝒏𝒏𝒂 𝒈𝒂𝒊𝒏 𝒅𝑩𝒊
𝑳 𝑻𝑿 = 𝑺𝒆𝒏𝒅𝒆𝒓 𝒍𝒐𝒔𝒔𝒆𝒔 𝒄𝒐𝒏𝒏𝒆𝒄𝒕𝒐𝒓𝒔 𝒆𝒕𝒄. 𝒅𝑩
𝑳 𝑭𝑺 = 𝑭𝒓𝒆𝒆 𝒔𝒑𝒂𝒄𝒆 𝒍𝒐𝒔𝒔 𝒅𝑩
𝑳 𝑴 = 𝑴𝒊𝒔𝒄. 𝒍𝒐𝒔𝒔𝒆𝒔 𝒎𝒖𝒍𝒕𝒊𝒑𝒂𝒕𝒉 𝒆𝒕𝒄. 𝒅𝑩
𝑮 𝑹𝑿 = 𝑹𝒆𝒄𝒆𝒊𝒗𝒆𝒓 𝒂𝒏𝒕𝒆𝒏𝒏𝒂 𝒈𝒂𝒊𝒏 𝒅𝑩𝒊
𝑳 𝑹𝑿 = 𝑹𝒆𝒄𝒆𝒊𝒗𝒆𝒓 𝒍𝒐𝒔𝒔𝒆𝒔 𝒄𝒐𝒏𝒏𝒆𝒄𝒕𝒐𝒓𝒔 𝒆𝒕𝒄. 𝒅𝑩
𝑺 𝑹𝑿 = 𝑹𝒆𝒄𝒆𝒊𝒗𝒆𝒓 𝒔𝒆𝒏𝒔𝒊𝒕𝒊𝒗𝒊𝒕𝒚 𝒅𝑩𝒎
PRX
[dBm]
Gain
Loss

10. © Peter R. Egli 2015
10/11
Rev. 1.00
LPWAN – Low Power Wide Area Network indigoo.com
6. Receiver sensitivity for LPWAN devices
Receiver sensitivity:
The required receiver sensitivity for a LPWAN device is derived from the calculated link budget.
The wireless link can be closed (communication between sender and receiver is possible) if the
receiver sensitivity SRX equals or is lower than (numerically in dB) the received power PRX.
Due to the long transmission paths that are typical for LPWAN systems, free space loss (path
loss) is the dominant factor that greatly reduces the received power at the receiver.
Therefore it is essential that LPWAN receivers, particularly device nodes, have a very good
receiver sensitivity (<= -140dBm), i.e. are able to receive signals levels that are 7 orders of
magnitude or more smaller than the transmission level at the sender.
𝑺 𝑹𝑿 <= 𝑷 𝑹𝑿

11. © Peter R. Egli 2015
11/11
Rev. 1.00
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7. Technologies for LPWAN
In the still evolving IoT and M2M markets, a few competing radio technologies are emerging.
Common to these technologies is the use of lower frequencies than 2.4GHz or 5.8GHz to
achieve better penetration into buildings or underground installations.
Work is still in progress in most of these technologies.
LPWAN
Technology
Standard /
Specificiation
Range Spectrum
ETSI LTN ETSI GS LTN 001 - 003 40 km in open field
Any unlicensed spectrum such as
ISM (433MHz, 868MHz, 2.4GHz)
LoRaWAN
LoRa Alliance
LoRaWAN
2-5km in urban areas
<15km in suburban
areas
Any unlicensed spectrum
868MHz (Eu)
915MHz (US)
433MHz (Asia)
Weightless-N Weightless SIG
<5km in urban areas
20-30km in rural areas
800MHz – 1GHz (ISM)
RPMA
Proprietary (On-Ramp
Wireless), planned to
become an IEEE
standard
<65km line of sight
<20km non line of
sight
2.4GHz