doc.: ieee 802.15-08-0583-02-004e submission september, 2008 kris pister et al.slide 1 project: ieee...
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doc.: IEEE 802.15-08-0583-02-004e
Submission
September, 2008
Kris Pister et al.Slide 1
Project: IEEE P802.15 Working Group for Wireless Personal Area Networks (WPANs)Project: IEEE P802.15 Working Group for Wireless Personal Area Networks (WPANs)
Submission Title: [Time Slotted, Channel Hopping Field Experience]
Date Submitted: [1 Sep, 2008]
Source: [Kris Pister, Lance Doherty, Rick Enns, Kuor Hsin Chang, Clint Powell, José A. Gutierrez, Ludwig Winkel] Companies [Dust Networks, Freescale, Emerson, Siemens AG]
Address [30695 Huntwood Avenue, Hayward, CA 94544 USA; 890 N. McCarthy Blvd, Suite 120, Milpitas, CA 95035 USA; 8000 West Florissant Avenue St. Louis, Missouri 63136 USA; Siemensallee 74, Karlsruhe, Germany]
Voice:[+1 (510) 400-2900, +1 (650) 327-9708, +1 (408) 904-2705, +1 (480) 413-5413, +1 (314) 553-2667, +49 (721) 595-6098]
E-Mail:[[email protected], [email protected], [email protected], [email protected], [email protected], [email protected], [email protected] ]
Re: [n/a]
Abstract: [This document proposes extensions for IEEE802.15.4 MAC]
Purpose: [This document is a response to the Call For Proposal, IEEE P802.15-08-373-01-0043]
Notice: This document has been prepared to assist the IEEE P802.15. It is offered as a basis for discussion and is not binding on the contributing individual(s) or organization(s). The material in this document is subject to change in form and content after further study. The contributor(s) reserve(s) the right to add, amend or withdraw material contained herein.
Release: The contributor acknowledges and accepts that this contribution becomes the property of IEEE and may be made publicly available by P802.15.
doc.: IEEE 802.15-08-0583-02-004e
Submission
September, 2008
Kris Pister et al.Slide 2
Time Slotted, Channel Hopping(TSCH) Field Experience
Kris Pister – UC Berkeley/Dust NetworksLance Doherty - Dust Networks
Rick Enns - ConsultantKuor Hsin Chang - Freescale
Clinton Powell - FreescaleJosé A. Gutierrez – Emerson
Ludwig Winkel – Siemens
September, 2008
doc.: IEEE 802.15-08-0583-02-004e
Submission
Overview
• Presents empirical result from a multi-channel multi-hop Industrial Deployment
• This is one of many working examples using TSCH technology.– Other examples at end of presentation if time
permits
• Measurement was taken for 26 days on all pair-wise channels in the network
doc.: IEEE 802.15-08-0583-02-004e
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September, 2008
Kris Pister et al.Slide 4
Printing Factory Field Experience Topics
• Network Topology & Location
• Network Protocols
• Time-Averaged Statistics
• Time Series Data
• Reliability in Uncertain Conditions
• Summary of Results
doc.: IEEE 802.15-08-0583-02-004e
Submission
September, 2008
Kris Pister et al.Slide 5
Network Topology
• 44 Nodes
• Gateway circled
• 2.5 hop mean
• Printing factory– 15,000 m2
– 3 floors– Concrete & steel
doc.: IEEE 802.15-08-0583-02-004e
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September, 2008
Kris Pister et al.Slide 6
doc.: IEEE 802.15-08-0583-02-004e
Submission
September, 2008
Kris Pister et al.Slide 7
doc.: IEEE 802.15-08-0583-02-004e
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September, 2008
Kris Pister et al.Slide 8
doc.: IEEE 802.15-08-0583-02-004e
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September, 2008
Kris Pister et al.Slide 9
Definitions
• Each node has two parents• Childparent connection is a path• TDMA hopping over 16 channels of 2.402.48 GHz• Each path composed of 16 path-channels• Stability is the hop-by-hop packet success rate• We measured stability on all path-channels
Child Parent
doc.: IEEE 802.15-08-0583-02-004e
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September, 2008
Kris Pister et al.Slide 10
Time-Averaged Stability for All Path-Channels
doc.: IEEE 802.15-08-0583-02-004e
Submission
September, 2008
Kris Pister et al.Slide 11
Time-Averaged Stability per Path
doc.: IEEE 802.15-08-0583-02-004e
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September, 2008
Kris Pister et al.Slide 12
An Example Low-Stability Path
• What does a path-channel look like?
• How does it vary with time?
• Let’s look at all 16 channels for a single path over time
doc.: IEEE 802.15-08-0583-02-004e
Submission
September, 2008
Kris Pister et al.Slide 13
26 Days: 2417 Path
2.40GHz
2.48GHz
doc.: IEEE 802.15-08-0583-02-004e
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September, 2008
Kris Pister et al.Slide 14
Three Paths
• Are paths geographically correlated?
56
44
47
17
doc.: IEEE 802.15-08-0583-02-004e
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September, 2008
Kris Pister et al.Slide 15
Three Paths - Stability Averaged over Time
doc.: IEEE 802.15-08-0583-02-004e
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September, 2008
Kris Pister et al.Slide 16
Three Paths - Stability Averaged over Time
doc.: IEEE 802.15-08-0583-02-004e
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September, 2008
Kris Pister et al.Slide 17
Three Paths - Channel 5 Over 26 Days
doc.: IEEE 802.15-08-0583-02-004e
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September, 2008
Kris Pister et al.Slide 18
Strategies to Overcome Variance
• Path diversity– Have multiple parents for each node
• Frequency diversity– Hop equally over all available channels
• Time diversity– Link-layer ACKs and retries– Tolerate duplicates
doc.: IEEE 802.15-08-0583-02-004e
Submission
September, 2008
Kris Pister et al.Slide 19
Reliability in the Midst of Variance
• 44 nodes, 80B payload per packet• 33 packets per 15 min per node• 3.6 million packets, 17 lost
– 99.9995% reliability over 26 days• All data secure and encrypted
doc.: IEEE 802.15-08-0583-02-004e
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September, 2008
Kris Pister et al.Slide 20
Expected Lifetime
Assuming 2xAA batteries (3000mAh)
Duty Cycle TX Current=20mA
RX Current=10mA
TX Current=60mA
RX Current=30mA
0.1% 100000 hr (= 11.4 yr) 33333 hr (= 3.8 yr)
1% 10000 hr (= 1.1 yr) 3333 hr (= 4.6 mo)
10 % 1000 hr (= 1.4 mo) 333 hr (= 0.5 mo)
100 % 100 hr (= 4.2 days) 33 hr (= 1.4 days)
doc.: IEEE 802.15-08-0583-02-004e
Submission
September, 2008
Kris Pister et al.Slide 21
Summary of Results
• Average over time and frequency good paths
• Individual frequencies have periods of poor performance
• Time-varying behavior unpredictable• Use network protocols to get mean behavior
doc.: IEEE 802.15-08-0583-02-004e
Submission
September, 2008
Kris Pister et al.Slide 22
Conclusions• Industrial environments have varying channels• Low-power single-channel systems will have failures• Cannot predict performance
– Average-case modeling software not applicable– Site surveys cannot capture behavior
• Problems would be more severe with interference• Can appropriately overprovision to get reliability
doc.: IEEE 802.15-08-0583-02-004e
Submission
2006: Cherry Point Refinery
• Scope limited to Coker facility and support units spanning over 1200ft
• No repeaters were needed to ensure connectivity
• Electrical/Mechanical contractor installed per wired practices
• >5 year life on C-cell
400m
doc.: IEEE 802.15-08-0583-02-004e
Submission
2006: Cherry Point Refinery
• Scope limited to Coker facility and support units spanning over 1200ft
• No repeaters were needed to ensure connectivity
• Electrical/Mechanical contractor installed per wired practices
• >5 year life on C-cell• >99.9% reliability400m
doc.: IEEE 802.15-08-0583-02-004e
Submission
Wireless HART interop demo, ISA 2006
Emerson
Siemens
Pepperl+Fuchs
ABB
Endress+Hauser
Honeywell
MACTek
PhoenixContact
Smar
Yokogawa
Siemens
Elpro
doc.: IEEE 802.15-08-0583-02-004e
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Grane Platform, North Sea• 22 pressure sensors• 2 hour installation vs. 2
days
WirelessSensors
doc.: IEEE 802.15-08-0583-02-004e
Submission
Shell Facility
2 km1 km
• Motor condition (vibration) monitoring• 200 temperature and vibration sensors• No line power due to hazardous location rules• Wiring in sensors would cause a 2 week delay in
“first gas”
HART Network
doc.: IEEE 802.15-08-0583-02-004e
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Pharmaceutical Process Monitoring• Temperature monitoring, latency tolerant, 100% of data
required to avoid severe economic impact
doc.: IEEE 802.15-08-0583-02-004e
Submission
Urban Infrastructure: Parking Monitoring
• SF pilot 07: hundreds
• LA pilot 08: 40,000
doc.: IEEE 802.15-08-0583-02-004e
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Reliable Performance in Harsh Environments
Wireless Sensor• Steel mills• Chemical processing • Food production• Urban Pavement• Rail cars• Cracking towers• Pharmaceutical manufacturing• Desert fences• Northern coal facilities• Oil and gas facilities• …
These and other factors conspire to define the difference between what works in the lab and what works in the real world!
Steel mill scarfer