A survey on LPWA technology: LoRa and NB-IoT Source: ICT Express , Volume 3, Issue 1,March 2017,Pages 14-21 Authors: Rashmi Sharan Sinha, Seung-HoonHwang , Yiqiao Wei Speaker:Bo-Yi Shiu Data: 11/09/2017

Outline Introduction Technical differences Network architecture MAC protocols Contention-based Random Access Comparison in terms of IoT factors Conclusion

Introduction Multi-mode

Network architecture(1/2)

Network architecture(2/2)

MAC protocols(1/3)

MAC protocols(2/3) Class-A : Bi-directional end-devices Downlink communications from the server at any other time will have to wait until the next scheduled uplink. Class-B: Bi-directional end-devices with scheduled receive slots Class B devices open extra receive windows at scheduled times. In order for the End-device to open it receive window at the scheduled time it receives a time synchronized Beacon from the gateway. Class C: Bi-directional end-devices with maximal receive slots Class C have nearly continuously open receive windows, only closed when transmitting.

MAC protocols(3/3) NAS (Non-Access Stratum) RRC (Radio Resource Control) PDCP (Packet Data Convergence Protocol) RLC (Radio Link Control) MAC (Medium Access Control) PHY (Physical)

Contention-based Random Access

Comparison in terms of IoT factors

Conclusion Both LoRa and NB-IoT have their own advantages and disadvantages according to its different technological principles. LoRa focuses on the low cost applications. NB-IoT is directed to applications that require high QoS and low latency.