Transcript pptx

Analysis of Capacity and Scalability of
the LoRa Low Power Wide Area
Network Technology
SPEAKER:CHAO-LIN TSAI
ADVISOR:DR.HO-TING WU
DATE:2017/01/19
Outline
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Introduction
LoRa
LoRa Technology
Three classes of EDs
LoRaWAN Performance
Conclusion
NEWS
Reference
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Introduction
Low Power Wide Area Network(LPWAN)
[5] Network type
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Introduction(cont.)
Low Power Wide Area Network(LPWAN)
The most critical factors in a LPWAN are:
 Network architecture
 Communication range
 Battery lifetime or low power
 Robustness to interference
 Network capacity (maximum number of nodes in a network)
 Network security
 One-way vs two-way communication
 Variety of applications served
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Introduction(cont.)
Low Power Wide Area Network(LPWAN)
[3] Fixed measurements points, 3km distance from TV tower LoRa IoT station
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Introduction(cont.)
Low Power Wide Area Network(LPWAN)
[5] LoRaWAN
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LoRa
What is it?
LoRa技術原是由一家法國公司Cycleo（成立於2009年，一個IP
和設計方案提供商）開發的一種擴頻無線調製專利技術，2012
年被SemTech公司以五百萬美金收購[8][10]。
而後，2013年4月SemTech公司發表的SX1272晶片中，就搭載
了LoRa技術。
在當時，一般使用FSK調變的歐洲智慧電錶收發器，最大傳輸
距離在 1 到 2 公里之間，而LoRa在相同條件下運作，傳輸距離
最遠則可超過 15 公里[9]。
(專利編號：EP2763321 from 2013 和 US7791415 from 2008)
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LoRa(cont.)
How it works?
LoRa® is based on chirp spread spectrum modulation.
[11]
[13]
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LoRa(cont.)
How it works?
Chirp + Spreading Factor (SF)
Explame SF=2
C2,1( 1 , 0 , 1 ) ↓
( 1 1 ,-1-1 , 1 1 )
C2,2( 1 , 0 , 1 ) ↓
( 1-1 ,-1 1 , 1-1 )
[12]
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LoRa Technology
Two major components
End device: ED
Base Station: BS
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LoRa Technology(cont.)
1.LoRa modulation
The use of signals with high bandwidth-time product
(BT>1) should make the radio signals resistant against
in band and out of band interferences, whilst the use
of sufficiently broadband chirps should help to fight
against heavy multipath fading characteristic for indoor
propagation and urban environments.
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LoRa Technology(cont.)
2.LoRaWAN network protocol
LoRaWAN network protocol which is optimized
specifically for energy limited EDs. As discussed
earlier, the LPWAN typically has star topology and
consists of BSs relaying data messages between the
EDs and an application server.
The BSs can be connected to the central server via
backbone internet protocol (IP) based link, and the
wireless communication based on LoRa or GFSK
modulation is used to move the data between EDs
and the BSs.
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LoRa Technology(cont.)
2.LoRaWAN network protocol
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Three classes of EDs
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LoRaWAN Performance
A LoRaWAN frame
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LoRaWAN Performance(cont.)
A LoRaWAN frame
[15] LoRa Packet Structure
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LoRaWAN Performance(cont.)
Time on Air(ToA)
SF : spreading factor
BW : bandwidth
NP : the number of preamble symbols
SW : synchronization word
For GFSK ,DR = 50kbit /s
PL : number of bytes of payload
IH : implicit header mode enable = 0, disable = 1
DE : set to 1 when use of the low data rate optimization,
0 when disabled
CR : coding rate from 1 to 4
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LoRaWAN Performance(cont.)
PHY layer payload
MType
000
001
010
011
100
101
110
111
Description
Join Request
Join Accept
Unconfirmed Data Up
Unconfirmed Data Down
Confirmed Data Up
Confirmed Data Down
RFU
Proprietary
備註
加入過程一 請求
加入過程二 接受
接收端不用回應
接收端不用回應
接收端必須回應
接收端必須回應
保留
可以用於實現自定義格式訊息，但只能在具有共同理解的
設備之間使用。
MHDR : MAC Header
MACPayload : MAC Payload of Data Messages
MIC : message integrity code
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LoRaWAN Performance(cont.)
Data rates settings and frames characteristics
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LoRaWAN Performance(cont.)
ED performance for the different data rates
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LoRaWAN Performance(cont.)
LoRaWAN channels in EU 863-873 MHz band
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LoRaWAN Performance(cont.)
Maximum throughput per LoRaWAN channel and ED
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LoRaWAN Performance(cont.)
LoRaWAN Capacity
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LoRaWAN Performance(cont.)
LoRaWAN Capacity
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LoRaWAN Performance(cont.)
LoRaWAN Capacity
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Conclusion
To sum up, one can see that LoRaWAN technology, like any
other, has its own strengths and weaknesses. Among the
former ones can be noted the high coverage and satisfactory
scalability under low uplink traffic.
The most critical drawbacks are low reliability and potentially
poor performance in terms of downlink traffic. Based on our
analysis, we suppose that LoRa can be effectively utilized for
the moderately dense networks of very low traffic devices
which do not impose strict latency or reliability requirements.
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NEWS
2017-01-11
Korea’s SK Telecom
plans to splash $4.2
billion on IoT and
Machine Learning
2016-06-30
KPN claims full national
coverage for its LoRa
LPWAN network.
2016-01-13
台北市IoT實驗平台第一季上線
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Reference
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[1] Konstantin Mikhaylov, Juha Petäjäjärvi, Tuomo Hänninen , “ Analysis of Capacity and
Scalability of the LoRa Low Power Wide Area Network Technology ,” In European Wireless
2016; 22th European Wireless Conference; Proceedings of, pages 1–6.
[2] Konstantin Mikhaylov, Jouni Tervonen, Joni Heikkilä and Janne Känsäkoski , “ Wireless
Sensor Networks in industrial environment: Real-life evaluation results ,” Future Internet
Communications (BCFIC), 2012 2nd Baltic Congress on Future Internet Communications.
[3] Tara Petrić, Mathieu Goessens, Loutfi Nuaymi, Laurent Toutain, Alexander Pelov, Telecom
Bretagne, “Measurements, Performance and Analysis of LoRa FABIAN, a real-world
implementation of LPWAN ,” 2016 IEEE 27th Annual International Symposium on Personal,
Indoor, and Mobile Radio Communications (PIMRC).
[4] N. Sornin , M. Luis , T. Eirich , T. Kramp , and O. Hersent , “ LoRaWAN specification ,” LoRa
Alliance Inc., San Ramon, CA, Ver. 1.0., January 2015 .
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Reference(Cont.)
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[5] LoRaWAN™ What is it? A technical overview of LoRa and LoRaWAN
[6] GFSK示意圖
[7] Libelium Adds LoRaWAN for Full Compatibility with Smart Cities Networks
[8] LoRa產品有那些？
[9] Semtech's SX1272 RFIC drives IoT, M2M deployments
[10] What is LoRa?
[11] Chirp spread spectrum
[12] Orthogonal variable spreading factor
[13] Frequency-shift keying
[14] 無線電通道的特性及緩解辦法
[15] sx1272
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