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TTCN-3 for

Wireless Sensor Networks

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TTCN-3 for WSNs

1. Background.

2. Introduction.

3. State of the art.

4. TTCN-3 application.

5. Conclusion.

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• Métodos y Tecnología is involved in different R&D&i project, bothnational and international using Wireless Sensor Networks (WSN):

µWSN (European Comission,FP6): Solving major problems in WSNs. ESNA (European, ITEA): Sensor network architecture.

RIMSI (Spain, PROFIT): Environmental control for buildings, and agriculture.

CENERGIA (Madrid, IMADE): Energy control.

SECURAREA (Madrid, IMADE): Radio frequency identification (RFID).

PERISEC (Spain, PROFIT): Perimeter security.

PROPSI (Spain, PROFIT): Environment monitoring.

GETSEC (Madrid, IMADE): Security for dangerous and valuable items.

Background

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• A WSN is a low rate WPAN (Wireless Personal Area Network) :• Compared to other WPAN, like Bluetooth:

WSNs are focused on control and automation, not in connectivity Use low data rate and low power consumption

Networks can support a large number of devices and a long range

Wireless

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The devices: motes

• The sensor nodes that constitute a network are commonly known as

motes.

• A mote is a very small device which typically includes:

A microcontroller.

Sensor(s) / Actuator(s) . Low frequency radio transciever.

A battery (two AA-s typically) .

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Network topology

• A sensor network normally constitutes a wireless ad-hoc network:

No network infrastructure is needed.

A node can always find a path to route the information.

Network Coordinator

Router

End Device

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Data processing

Data collected by the sensors are routed to a client for processing

MOTES SERVER CLIENT

MESH NETWORK

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State of the art

• The firmware for each mote has a different protocol stack depending on

the vendor.

• There is only a standard defined for the two lowest OSI layers:

IEEE802.15.4.

• There are currently different solutions for the rest of the layers, no widely

adopted standard.

ZigBee: “home” applications. WirelessHART and ISA SP-100.11: industrial automation.

6lowpan: IPv6 over IEEE802.15.4.

Zensys' Z-Wave and Coronis' Wavenis: propietary.

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State of the art (II) • Different and specific Operating Systems are also used:

TinyOS

Contiki

MANTIS

• Algorithmic research in WSN mostly focuses on the design of energy

aware algorithms for data transmission.

• Different routing algorithms used: pro-active, reactive, flow oriented,

hybrid.

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What to test

• What needs to be tested:

Single motes firmware (one mote + one simulation).  Network protocols (several motes cooperating).  Final application services (whole network + application) .

• What could be done purely with TTCN-3:

Everything, except simulating the physical parameters

Great advantage in portability, since the tests will be written just once

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Problems

• General problems:

Great number of motes: complicated deployment.

Many phisical related parameters.

Only physical and link protocols are standard.

• TTCN-3 specific:

System Adapter complicated.

Extra software to add physical models

• Applications are tested with the use of simulators/emulators

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TTCN-3 solution

• Embedded system problem

• Some approaches have been identified:

RADIO SIMULATION

To simulate thewhole protocolstack

EMULATION

Use an emulator to beable to embed thesystem in a PC

USE OF A GATEWAY

Issue commandsto the WSN

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Emulation

• Bring the application to our PC

• Test the functionality and the routing protocols

• Able to emulate as many motes as desired

• Drawback: unrealistic

TTCN-3 code

Adapter

Application

Emulation

Specific OS

TCP/IP (or different processes)

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Radio simulation

• Connect with real motes through a radio interface

Full PC simulation (radio card)

Coordinator mote connected through a port (drivers)

Useful on the field Drawback: less flexible

TTCN-3 code

Radioadaptation

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Gateway

• Play the role of the final application

• Can send commands to the network

• Motes working on demand

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Conformance testing

• ZigBee defines PICS (Protocol Implementation Conformance Statement):

IEEE 802.15.4 PICS

Network layer PICS

Security PICS

Application layer PICS

• PICS proforma:

M Mandatory

O Optional

O.n Optional, but support of at least one of the groups labeled

N/A Not applicable

X Prohibited

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Conclusions

• WSN is a growing technology that will become widely used in the near

future

• Different solutions are currently used, in which testing has not been

satisfactory resolved yet

• TTCN-3 could be adopted for a variety of reasons:

Ease the deployment

Evaluate routing algorithms

Portability/conformance

• Physical parameters could be introduced by combining TTCN-3 with

specific hardware or software

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