View
227
Download
1
Tags:
Embed Size (px)
Citation preview
A simple data-muling protocol**
Pablo Basanta Val
Marisol García-Valls Miguel Baza-Cuñado
**Accepted in IEEE Transactions on Industrial informatics (I.F.: 3.1).
http://www.it.uc3m.es/drequiem/
Outline
• Introduction
• The D&U Data-Muling Protocol
– Constraints &Model
– Discovery and Updates
• D&U Evaluation
– Mote characterization
– Benchmark Results
• Conclusions
2 JTR 2014
Introduction
• Traditional industrial infrastructures were wired
– There a trend towards wireless infrastructures (IWSNs)
– Future industrial infrastructures would be hybrid (wired+wireless)
• In addition to wired and wireless, infrastructures may extend wired and wireless with data-muling
– To have a more flexible infrastructure
JTR 2014 3
Wired, Wireless and Data-Muling in an Industrial Infrastructure
• Potentiality: – Versatility in supporting different applications
– Data-muling in industrial infrastructures (e.g. a train) is more predictable than in general (random muling behaviour of people) scenarios
JTR 2014 4
Some challenges for industrial data-muling [CH1] Resource constraints related to energy, memory and CPU - Mules and motes may have energy constraints and run on embedded
devices [CH2] Topology problems and environmental issues. - Networks that appear and disappear dynamically [CH3] Quality of service requirements [CH4] Redundancy [CH5] Security [CH6] Deployment and ad-hoc integration [CH7] Internet integration.
- Access from other higher order networks This work is mainly concerned with CH1 CH2 and CH7.
JTR 2014 5
D&U Data Mulling Protocol Bounds and Limitations
• Actors: 1) motes, 2) host nodes and 3) the mules • Communications
– Intermittent communications and no direct vision among different motes
• Energy constraints – In the mule but not in the motes (they have a supply source)
JTR 2014 6
D&U Data Mulling Protocol The protocol
JTR 2014 7
• Periodically, the mote looks for other nodes with sleep periods
D&U Data Mulling Protocol Node Discovery subprotocol
JTR 2014 8
JTR 2014 9
D&U Data Mulling Protocol Basic Data Update (of b and a) in the D&U protocol
• Two steps for downloading data: – Clock synchronization for each mule to mote interaction
– Data transmission
D&U Data Mulling Protocol data model
JTR 2014 10
• Communication model: -A distributed data table with motes that read and write data -Synchronized by the mule
D&U Data Mulling Protocol Data freshness
JTR 2014 11
Implementation hardware
• The mule and the mote run the same hardware
– On Java’s SunSPOT – Software modified to run more efficiently
JTR 2014 12
Description
CPU ARM920T -32 bits (ARMv4) at 180MHz
Memory S71PL032J40 Mem
512 KBytes pSRAM and
4 Mbytes NOR Flash
Network TI CC2420 at 2,4 GHz (IEEE 802.15.4)
Battery Li-ION de 3,7V (720 mAh)
I/O
ports
1 x USB 1.1/2.0, 2 x UARTs,
5 x general purpose I/O Ports
802.15.4
setup
Tx pot.=-3dbm and freq 26 (2480 Mhz)
Max transmission distance= 10 meters
API
facilities
Clock access and battery access via API
Send/Receive data via connections or
diffusion (802.15.4)
Mode Consumption
(mAh)
Duration
Run mode 70-120 mAh 6-10 hours
Shallow-sleep
mode
24 mAh 30 hours
Deep sleep mode 32 µAh 22500 hours
Mote Wakeup
time
70-120 mAh 10 ms (max)
Energy model of the mote
Implementation software stack and protocols
JTR 2014 13
Empirical evaluation General issues
JTR 2014 14
Based on the iLAND project and other internal real-time Java benchmarks
Empirical evaluation Mote characteristics: data rate and energy costs
JTR 2014 15
Empirical evaluation Mote characteristics: mule speed
JTR 2014 16
• The maximum update time in ideal conditions - clocks perfectly synchronized - Mote detected as soon as the mote is in the 10 meters range.
Empirical evaluation Mote characteristics: maximum data transferred
• non-feasible area – 1 mote and 1 mule at 330
km/h
– 128 motes with a mule at 5km/h.
• Original vs. D&U protocol – 25% of additional motes
JTR 2014 17
Empirical evaluation Mote characteristics: battery profile
• With (TIUmin=1 hour) and (TIDmin=1 second) – 18000 hours of operation
– Ideal data-mulling add 15% of energy
JTR 2014 18
Benchmark Memory in the mule
• Infeasibility area
- 512 bytes sampling period of 2.5 minutes
- with 1 byte and 10 milliseconds)
• Idealized version may add 100% to 190% additional motes
JTR 2014 19
Benchmark Time in the mule
• Feasibility area – 1byte-2us intra period
– 512 bytes-2 ms intra period range
• With an idealized protocol you may add 20% to 190% more motes
JTR 2014 20
Benchmark Energy in the mule bound
• The mule may recharge in each round
• Infea
• sibility area
- [1 byte each 3µs]
- [512 bytes each second]
• The Ideal data-muling protocol improves by 25% to 197%
JTR 2014 21
Conclusions and ongoing work
• Proposed a new communications protocol – Called the D&U protocol that runs on IEEE
802.15.4
• Evaluation results highlight the importance of having save energy strategies – Identified an idealized protocol
• Ongoing work – To extend this results to other protocols
– E.g. 802.11 and DPWS, UPnP
JTR 2014 22