The slides provide an insight into different IoT and M2M specific protocols. Their main features and differences are highlighted. Potential research area in IEEE 802.11ah is identified. The slides also identifies the coexistence problem between Lora and Sigfox

1. AN OVERVIEW OF
LoRa, SigFox, and IEEE
802.11ah
Faheem Zafari
Computer & Information Technology
Purdue University
faheem0@purdue.edu

2. AGENDA
• LoRa
• SigFox
• IEEE 802.11ah
• Differences between LoRa, SigFox, IEEE 802.11ah
• Use cases
• Problem with IEEE 802.11ah
• Co-existence problem

3. LoRa
• Physical Layer LPWAN solution
• High range (max 15km), low power, low data rate (0.3-
37.5 kbps), wideband, sub-GHz
• The architecture consists of
• LoRa end-devices
• LoRa Gateways
• LoRa Network Servers (NetServer)
Taken from Centenaro et al.

4. LoRa
• The MAC layer is basically ALOHA protocol controlled by
the LoRa NetServer.
• The LoRa MAC is designed to mimic IEEE 802.15.4 Mac
to allow the accommodation of other protocols such as
CoAP, 6LoWPAN etc.
Taken from Centenaro et al.

5. • SIGFOX
• First LPWAN technology.
• The physical layer uses
Ultra-Narrow Band (UNB)
wireless modulation.
• Network layer protocols
are ‘secret sauce’.
• Low throughput (~100
bps), low power, extended
range (up to 50 km).
• The end device must use
SIGFOX modem to
connect to the SIGFOX
network
• The device should initiate
the communication.

6. • IEEE 802.11ah
• Physical layer based on 802.11ac.
• Low Data Rate (~100kpbs), extended range (up to 1km),
low energy consumption, sub-GHz.
• One hop network topology.
• Supports MIMO, Single user beamforming etc on the
Physical layer.
• Three different types of stations supported
• Traffic Indication Map (TIM): Listens to AP for data transfer
• Non-TIM stations: Directly negotiate with AP during
association process to obtain transmission time on Periodic
Restricted Access Window (PRAW)
• Unscheduled Stations: does not listen to any beacons and
uses poll to access channels.

7. • IEEE 802.11ah

8. MAIN DIFFERENCES
Parameter LoRa Sigfox IEEE 802.11ah
Data rate (kbps) 0.3-37.5 0.1 >100
Coverage (km) Rural: 10-15
Urban: 3-5
Rural: 30-50
Urban: 3-10
1
Nodes per BS ≈ 104
≈ 106 8191
Frequency (MHz) Various,
Sub-Ghz
969 or 902 902-928 (US)
Initiation Both node
and
NetServer
Device Both device
and the AP
Energy
Consumption
Very low low slightly higher
Dedicated
Network
No Yes No

9. USE CASES
Technology Use Cases
LoRa Garbage collection bin fill level for pick up
route optimization
Sigfox Smart meters, smoke detectors
IEEE 802.11 ah Backhaul network for Sensors, Video
Surveillance, wearable consumer
electronics

10. PROBLEM WITH IEEE 802.11ah
• As pointed out by Adame et al., a potential challenge in
802.11ah is the performance of Non-TIM and
unscheduled stations, and their integration with TIM
stations in a single WLAN. The problem is interesting to
explore for further research.
• The number of stations that IEEE 802.11ah is also much
lesser than Sigfox and LoRa.

11. COEXISTENCE PROBLEM
• One of the problems with the coexistence of Sigfox and
LoRa is that, Sigfox is based on UNB sub-GHz while
LoRa is wideband sub-GHz. The wideband solution is
prone to the interference from UNB technologies. This
problem can be interesting to explore for further research.

12. REFERENCES
• Adame, T., Bel, A., Bellalta, B., Barcelo, J., & Oliver, M. (2014). IEEE
802.11 AH: the WiFi approach for M2M communications. Wireless
Communications, IEEE, 21(6), 144-152
• Centenaro, M., Vangelista, L., Zanella, A., & Zorzi, M. (2015). Long-
Range Communications in Unlicensed Bands: the Rising Stars in
the IoT and Smart City Scenarios. arXiv preprint arXiv:1510.00620.
• Centenaro, M., Vangelista, L., Zanella, A., & Zorzi, M. (2015). Long-
Range Communications in Unlicensed Bands: the Rising Stars in
the IoT and Smart City Scenarios. arXiv preprint arXiv:1510.00620.
• Keysight Technology. Explosion of the Internet of Things: What does
it mean for wireless devices? June, 2015