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

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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

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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.

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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)

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D&U Data Mulling Protocol The protocol

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• Periodically, the mote looks for other nodes with sleep periods

D&U Data Mulling Protocol Node Discovery subprotocol

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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

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• Communication model: -A distributed data table with motes that read and write data -Synchronized by the mule

D&U Data Mulling Protocol Data freshness

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Implementation hardware

• The mule and the mote run the same hardware

– On Java’s SunSPOT – Software modified to run more efficiently

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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

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Empirical evaluation General issues

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Based on the iLAND project and other internal real-time Java benchmarks

Empirical evaluation Mote characteristics: data rate and energy costs

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Empirical evaluation Mote characteristics: mule speed

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• 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

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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

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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

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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

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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%

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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

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http://www.it.uc3m.es/drequiem/

23 JTR 2014