This document provides an overview and comparison of LoRa and NB-IoT low-power wide area network (LPWA) technologies. It discusses that both technologies were developed for applications requiring long battery life and low data rates. LoRa is an unlicensed standard based on chirp spread spectrum modulation, while NB-IoT is a licensed narrowband cellular standard developed by 3GPP. Key differences are that LoRa has lower device costs and supports higher latencies, while NB-IoT can leverage existing cellular networks and has higher data rates. In conclusion, LoRa is a new dedicated technology for IoT platforms, while NB-IoT uses existing cellular infrastructure.

1. LoRa and NB-IoT
Gagan Gupta, Darshan Patil
gagan@kth.se, darshan@kth.se
13 October 2016

2. OUTLINE
● Background
● Motivation
● LoRa
● NB-IoT
● Conclusion

3. Background
IoT- Billion of Connected Devices
Radio Access ??
Different Applications have different set
of Requirements
● Cost
● Data Rate
● Latency
● Energy Consumption
● Voice, Multimedia (high data rate) → Legacy cellular
licensed solutions, unlicensed WLAN solutions
● Industrial, commercial, sensors and IoT (low data
rate) → IEEE 802.15.4, LPWA, BT, ZigBee

4. Motivation
● IOT devices have requirements of wide area
connectivity for low power and low data rate
devices at economical cost
● Legacy cellular solutions- high throughput,
long range, but high power and costly
● WLAN 802.11 a-n- high throughput, short
range, moderate-high power and cost
● LPWA- Tradeoff between above (Some
technologies like LoRa and NB-IoT)
● LPWA- For applications that require
multi-year batteries and send small
amount of data less frequently
● Also, involving long range
communications with low power
● Applications like Smart meter, seismic
sensors, environmental monitoring,
smart grid etc.

5. LPWA standards
● LoRa / LoRaWAN-
○ Set up by industrial
consortia
○ Unlicensed
● NB-IoT- Narrow band IoT
○ Set up by 3gpp
○ licensed
Reference: Course textbook

6. LoRa ( Long Range)
● LoRa is the proprietary physical layer or
the wireless modulation technique
utilized to create long Range
Communication Link
● Based on chirp spread spectrum
modulation
● A single gateway or base station can
cover entire cities or hundreds of
square kilometers
Chirp Signal

7. LoRaWAN (Long Range Wide Area Network)
● Star of Stars Topology
● Nodes connect to multiple
gateways.
● No handover needed from
gateway to gateway
● Nodes are asynchronous and
communicate when they have
data to send
● Device Classes-All nodes are not
equal
● Division based on tradeoff between
communication latency versus
battery life time.
● Class A -Battery powered sensors
● Class B- Battery powered actuators
● Class C- Main Powered actuators

8. LoRaWAN (Long Range Wide Area Network)

9. NB-IoT (Narrow band IoT)
● Technology standardized by the 3GPP standards body
● Narrow band Technology designed for IoT which can be deployed in GSM
and LTE Spectrum
● Also termed as cellular based IoT
● Standardization of NB-IoT completed with Release 13 of 3GPP published
on 22 June 2016
● To be launched in early 2017

10. NB-IoT (Narrow band IoT)
❖ Highest modulation scheme used- QPSK
❖ Minimal noise level inside a single narrowband
❖ Receiver does not require to add processing gain to decode
❖ Simple and inexpensive transceiver design
● Transmission schemes:
○ minimum system bandwidth for
both downlink and uplink - 180
kHz
○ GSM carrier of 200 kHz,
○ 1 PRB (Physical Resource Block)
inside an LTE carrier/ guardband
could be replaced by NB-IoT
carrier.
○ 12 subcarriers of 15 kHz in
downlink using OFDM and 3.75/
15 kHz in uplink using SC-FDMA
○ Various deployment options
REDUCED
POWER
&
LOW COST

11. NB-IoT (Narrow band IoT)
● To enable low-complexity UE implementation, NB-IoT allows only one HARQ
process in both downlink and uplink, and allows longer UE decoding time
● Asynchronous, adaptive HARQ procedure is adopted to support scheduling
flexibility.
● Physical Channel/ Resource mapping
○ Extensive reuse of current LTE
(Long Term Evolution)
specifications
○ Few changes to physical channels
used in LTE (detailed review)
● Random Access :
○ *Contention based algorithm
similar to LTE [*Source- A Primer
on 3GPP Narrowband Internet of
Things (NB-IoT)]
UE
N/W
1
2
3
4
1. Preamble
2. Response containing advance
command and scheduling of the uplink
resources for the UE to use
3. Identity to the network
4. Contention resolution message

12. NB-IoT (Narrow band IoT)
● Time acquisition and synchronization
○ Critical- (Low cost Oscillators, deployment style introduces additional frequency
offsets)
○ Changes to the design of synchronization sequences in LTE
● Various pedagogical estimations and signal processing schemes are considered to estimate
time delay and synchronization in LTE (detailed review and reference for figure)

13. NB-IoT (Narrow band IoT)
Source: NB-IoT, Accelerating Cellular IoT, Huawei

14. LoRa and NB-IoT overview
Feature LoRa NB-IoT
Licensed/Unlicensed
Spectrum
Unlicensed Band Licensed Band
Reuse of Cellular Network No Yes
Development Status Existing Yet to develop
Modulation SS chirp QPSK
Bandwidth 500 Hz - 125 KHz 180 KHz
Data Rate 290 bps- 50 kbps 250 kbps max
Device cost/ complexity 1-5 $ (Ref- LPWA survey) < 5$ per module (Ref-IETF)
Latency and Battery Lifetime > 10 years <10 seconds, >10 years battery
(Ref-IETF)
Type of Standard Proprietary open

15. Conclusion
● We have studied -
○ Why?
■ IoT is need of the time.
○ How it can be achieved?
■ LPWA standards like NB-IoT and LoRa were discussed and
compared.
○ What?
■ Is LoRa: Entirely new technology adapted to the need of IoT
platform
■ Is NB-IoT: Use of existing cellular infrastructure

16. References
NB-IOT:
Maximum-Likelihood Detection for Energy-Efficient Timing Acquisition in NB-IoT
https://arxiv.org/pdf/1608.02427.pdf
A Primer on 3GPP Narrowband Internet of Things (NB-IoT)
https://arxiv.org/pdf/1606.04171.pdf
NB-IoT by IETF
https://www.ietf.org/proceedings/96/slides/slides-96-lpwan-7.pdf

17. Thank You !!