doc.: IEEE e Submission September, 2008 Kris Pister et al.Slide 1 Project: IEEE P 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 USA; 890 N. McCarthy Blvd, Suite 120, Milpitas, CA USA; 8000 West Florissant Avenue St. Louis, Missouri USA; Siemensallee 74, Karlsruhe, Germany] Voice:[+1 (510) , +1 (650) , +1 (408) , +1 (480) , +1 (314) , +49 (721) ] Re: [n/a] Abstract:[This document proposes extensions for IEEE MAC] Purpose:[This document is a response to the Call For Proposal, IEEE P ] Notice:This document has been prepared to assist the IEEE P 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 P

doc.: IEEE e Submission September, 2008 Kris Pister et al.Slide 2 Time Slotted, Channel Hopping (TSCH) Field Experience Kris Pister – UC Berkeley/Dust Networks Lance Doherty - Dust Networks Rick Enns - Consultant Kuor Hsin Chang - Freescale Clinton Powell - Freescale José A. Gutierrez – Emerson Ludwig Winkel – Siemens September, 2008

doc.: IEEE e 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 e Submission 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 e Submission September, 2008 Kris Pister et al.Slide 5 Network Topology 44 Nodes Gateway circled 2.5 hop mean Printing factory –15,000 m 2 –3 floors –Concrete & steel

doc.: IEEE e Submission September, 2008 Kris Pister et al.Slide 6

doc.: IEEE e Submission September, 2008 Kris Pister et al.Slide 7

doc.: IEEE e Submission September, 2008 Kris Pister et al.Slide 8

doc.: IEEE e Submission September, 2008 Kris Pister et al.Slide 9 Definitions Each node has two parents Child  parent connection is a path TDMA hopping over 16 channels of 2.40  2.48 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 e Submission September, 2008 Kris Pister et al.Slide 10 Time-Averaged Stability for All Path- Channels

doc.: IEEE e Submission September, 2008 Kris Pister et al.Slide 11 Time-Averaged Stability per Path

doc.: IEEE e Submission 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 e Submission September, 2008 Kris Pister et al.Slide Days: 24  17 Path 2.40GHz 2.48GHz

doc.: IEEE e Submission September, 2008 Kris Pister et al.Slide 14 Three Paths Are paths geographically correlated?

doc.: IEEE e Submission September, 2008 Kris Pister et al.Slide 15 Three Paths - Stability Averaged over Time

doc.: IEEE e Submission September, 2008 Kris Pister et al.Slide 16 Three Paths - Stability Averaged over Time

doc.: IEEE e Submission September, 2008 Kris Pister et al.Slide 17 Three Paths - Channel 5 Over 26 Days

doc.: IEEE e Submission 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 e 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 – % reliability over 26 days All data secure and encrypted

doc.: IEEE e Submission September, 2008 Kris Pister et al.Slide 20 Expected Lifetime Assuming 2xAA batteries (3000mAh) Duty CycleTX Current=20mA RX Current=10mA TX Current=60mA RX Current=30mA 0.1% 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 e 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 e 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 e 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 e 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% reliability 400m

doc.: IEEE e Submission Wireless HART interop demo, ISA 2006 Emerson Siemens Pepperl+ Fuchs ABB Endress+ Hauser Honeywell MACTek Phoenix Contact Smar Yokogawa Siemens Elpro

doc.: IEEE e Submission Grane Platform, North Sea 22 pressure sensors 2 hour installation vs. 2 days Wireless Sensors

doc.: IEEE e Submission Shell Facility 2 km 1 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 e Submission Pharmaceutical Process Monitoring Temperature monitoring, latency tolerant, 100% of data required to avoid severe economic impact

doc.: IEEE e Submission Urban Infrastructure: Parking Monitoring SF pilot 07: hundreds LA pilot 08: 40,000

doc.: IEEE e Submission 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